When selecting oils it is important to look at the fatty acid content.  Oils high in linoleic acid are very good for oily, combination and acne prone skin, but they are prone to going rancid quickly.  Butters are very occlusive and tend to have a longer shelf life. Their high Stearic and/or Palmitic acid content help lock in moisture so are good for dry and dehydrated skin.

When formulating creams it is important to have a balance of different oils and butters to create a cream that has a good skin feel. In the industry you will often hear people talk about spreading cascades to define the skin feel of a product.  This was coined by Henkel (now part of Cognis) and describes the different spreading values of emollients. Accordingly oils can be classified as fast, medium and slow spreading.  A fast spreading oil will disperse quickly on the skin than a slower spreading oil. Using high amounts of fast spreading oils is likely to leave a very thin film on the skin leaving it soft however the effects will disappear quickly and may leave your skin feeling dry. Conversely using a high levels of slow spreading oils or butters will leave a fatty layer on the skin which is not likely to disperse quickly and will feel heavy.  Using a combination of fast, medium and slow spreading oils will have a synergistic effect on the skin feel of the product as well as how long it is able to lock in moisture and keep the skin feeling supple.

Below is a basic guide to selecting different vegetable oils for your skincare products. This is based on my own observations and is somewhat subjective especially when we come to the fast and medium fast spreading oils. This is just a starting point and you may find that you disagree with some of my conclusions.

OILY/ACNE PRONE/COMBINATIONSENSITIVEDRY/DEHYDRATED
POMEGRANATE (F)BORAGE (F)WALNUT
KIWI (F)JOJOBA (F-M)SWEET ALMOND
CAMELLIA (F)NEEM OIL SHEA OIL (S)
THISTLE (SAFFLOWER) (F)CALENDULA INFUSEDSHEA BUTTER (V S)
HEMP (F)PEACH KERNEL (M)OLIVE
POMEGRANATE CO2 (F)EVENING PRIMROSE (F)MORINGA
COCO CAPRYLATE (VF)HEMP SEED OILMACADAMIA NUT (F-M)
CASTOR (S)ROSEHIP (F)ILLIPE BUTTER (V V S)
CAMELINA (F)MULLEIN INFUSEDHAZELNUT (F)
BLACKSEED (F-M)BLACKSEED (F-M)COCOA BUTTER (V V S)
OLIVE SQUALANE (F)SUNFLOWER SEED OIL CAPRIC/CAPRYLIC TRIGLYCERIDE (M-F)
ISOAMYL LAURATE (VF)COMFREY INFUSED OIL CAMELINA (F)
JOJOBA (F-M)APRICOT KERNAL (M)AVOCADO
CAPRIC/APRYLIC TRIGLYCERIDE (M-F)CAPRIC/CAPRYLIC TRIGLYCERIDE (M-F)ARGAN (M)
PRICKLY PEAR /BARBARY FIG (F)COCO CAPRYLATE
NEEM OIL (M)ISOAMYL LAURATE
SUNFLOWER (F-M)
MANGO BUTTER (SLOW AND DRY)
PAIGNYA BUTTER (SLOW AND VERY DRY)
MATUREEYE CARE PRODUCTS
PUMPKIN (M)RICE BRAN (F-M)
KAHAI (FAST)SEA BUCKTHORN
POMEGRANATE (F)CAMELINA (F)
ROSEHIP CO2 AND OIL (F)CAMELLIA (F)
SEA BUCKTHORN CO2 (M)THISTLE (F)
ARGAN (M)POMEGRANATE (F)
CAMELINA (F)ISOAMYL LAURATE (VF)
EVENING PRIMROSE (F)COCO CAPRYLATE (VF)
WALNUT (F)HAZELNUT (F-M)
PRICKLY PEAR (F)
MACADAMIA NUT (F-M)

 

 

 

 

There are many types of honey with varying properties. Most people like to eat it but some of us also like to put it on our  skin.  Most people also know about Manuka honey and its purported anti bacterial properties. Lesser known is Sidr honey which comes from the nectar of the Sidr tree in Yemen and is rare, limited in supply and  expensive.   But, honey in general has been studied extensively, particularly its use in wound healing.  There appears to be a fascination around the anti bacterial nature of honey, in the available literature.  So what do we know about honey, how is it defined and classified; and how can honey be beneficial in skincare? First lets have a look at what honey is and where it comes from.

What is honey?

Honey is the natural sweet substance produced by honey bees from nectar or blossoms or from the secretion of living parts of plants or excretions of plants, which honey bees collect, transform, and combine with specific substances of their own to ripen and mature1. It is also defined as the nectar and saccharine exudation of plants, gathered, modified and stored as honey in the honeycomb by honeybees, Apis melifera” (P. Olaitan et al., 2007)

How is honey classified under EU law?

The EU Directive defines honey as, “the natural sweet substance produced by Apis mellifera bees from the nectar of plants or from secretions of living parts of plants or excretions of plant-sucking insects on the living parts of plants, which the bees collect, transform by combining with specific substances of their own, deposit, dehydrate, store and leave in honeycombs to ripen and mature.”

In addition to the above honey has to meet certain “composition and quality  criteria” to be called honey.   To be placed on the market it must:

1) not have any additions other than honey;
2) as far as possible, be free from organic or inorganic matter foreign to its composition;
3) not have any foreign tastes or odours, signs of fermentation or artificially changed acidity or have been heated in such a way that the natural enzymes have been either destroyed or significantly inactivated.

Honey must also  comply with the following physico-chemical characteristics:

1) fructose and glucose content in blossom honey not less than 60 g/100 g; in honey dew honey and blends of honeydew honey with blossom honey not less than 45 g/100 g;
2) sucrose content not more than 5 g/100 g; in honey obtained from false acacia (Robinia pseudoacacia), alfalfa (Medicago sativa), Menzies Banksia (Banksia menziesii), French honeysuckle (Hedysarum), red gum (Eucalyptus camadulensis), leatherwood (Eucryphia lucida), dwarf leatherwood (Eucryphia milliganii) or citrus (Citrus spp.) not more than 10 g/100 g; in honey obtained from lavender (Lavandula spp.) or borage (Borago officinalis) not more than 15 g/100 g;
3) moisture content not more than 20 %; in heather (Calluna) and baker’s honey not more than 23 %; in baker’s honey from heather not more than 25 %;
4) water-insoluble content not more than 0.1 g/100 g; in pressed honey not more than 0.5 g/100 g;
5) electrical conductivity not more than 0.8 millisiemens per centimetre; in honeydew and chestnut honey and blends of these not less than 0.8 mS/cm, except for honey obtained from the strawberry tree (Arbutus unedo), bell heather (Erica), eucalyptus, lime (Tilia spp.), ling heather (Calluna vulgaris), manuka or jelly bush (Leptospermum) or the tea tree (Melaleuca spp.);
6) free acid content not more than 50 milli-equivalents per 1 000 grams; in baker’s honey not more than 80 milli-equivalents per 1 000 grams;
7) diastase activity after processing and blending (Schade scale) not less than 8, except baker’s honey; diastase activity in honeys with low natural enzyme content (e.g. citrus honeys) and a hydroxymethylfurfural (HMF) content of not more than 15 mg/kg, not less than 3;
8) hydroxymethylfurfural content after processing and blending not more than 40 mg/kg, except for baker’s honey and having regard to the HMF content referred to in 7 above; in honeys from regions with a tropical climate and blends of these honeys not more than 80 mg/kg. (The Honey (England) Regulations 2015)

How is honey made?

We all know that honey comes from bees. But, by what mechanism does nectar become honey?

There are different types of bees in a colony, each with their own distinct function for the hive.  Forager bees that collect nectar (the sweet watery sugary substance found in flowers) from nearby flowering plants. These foragers drink the nectar and hold it in their stomachs or ‘crop’ They transport it back to the hive where they are met by the ‘processor’ bee.  The foragers regurgitate the nectar directly into the  stomach of the processor bee near the entrance of the hive.

The forager then carries on his task of collecting more nectar and the processor takes the nectar to the honey comb, near the top of the hive, regurgitating it into the hexagonal wax cell where it is left to ripen.

Crucial in the processing of honey is the enzyme invertase.  The processor bee adds invertase every time they regurgitate the nectar.  This breaks the sucrose – contained in the nectar – down into simple sugars; mainly glucose and fructose.    Once the honey is in the hive it needs to ripen. Ripening is the process whereby the nectar, which contains 70% water is reduced to around an 17-23% water and sugar solution. Again, honey bees are crucial in the evaporation of water.  They frantically fan their wings, creating airflow in the hive and around the honeycomb which helps to evaporate the water from the nectar creating a highly viscous solution.

Once the nectar has ripened into honey, it contains such a small amount of water and such a high amount of sugars that microbes can not grow in it (this is not to say that they do not remain dormant).  At this point the bees will cap the honey with wax to stop any moisture getting in and causing it to spoil.

Water activity and water content of honey

“Due to the high content of monosacharides (fructose and glucose) and relatively low moisture content, the water activity of honey is usually, but not always, below 0.60 which is enough to inhibit the growth of osmotolerant yeasts (Beckh, Wessel, & Lüllmann, 2004; Ruegg & Blanc, 1981; Zamora & Chirife, in press).”

How is honey beneficial to skin?  

Honey is beneficial in a number of ways – it has humectant, antibacterial, occlusive qualities and is a natural exfoliant due to its natural pH and polyhydroxy acid; gluconic acid.  It is thought that for this reason honey has been used traditionally for wound healing and has re-emerged as a strategy for treating wounds infected with bacteria resistant to antibiotics.

Natural antibacterial 

The natural anti bacterial properties of honey have been studied extensively and it is clear that honey is a strong antimicrobial.  Research has found that the anti bacterial quality is most likely from the hydrogen peroxide, its low pH and the presence of gluconic acid. Hydrogen peroxide is formed from the glucose oxidase, an enzyme that comes from bees when it regurgitates the honey into the honeycomb.  It plays an important part in forming gluconolactone which then transforms into gluconic acid and hydrogen peroxide. The gluconic acid is the main acid in honey and accounts in part to its acidic pH. Although  gluconolactone is not present in honey once it has ripened however, if diluted gluconolacone  becomes active again (http://www.airborne.co.nz/enzymes.shtml).

Natural PHA  

The polyhydroxy acid found in honey is gluconic acid. There are other acids, namely alpha hydroxy acids such as  citric and malic acid which help keep the pH of honey to on average of about 3.9.   Polyhydroxy acids (PHAs) have a similar effect as alpha hydroxy acid, including exfoliation, skin soothing, anti ageing and anti – photo ageing effects without causing irritation that AHA’s may cause. They have been found compatible with sensitive skin including rosacea and atopic dermatitis and can be used after cosmetic surgery.  PHA’s can also help with moisturisation and are a great humectant.  They have also been found to increase skins barrier function.  A combination of the PHA and low pH makes the topical use of  honey good for all skin types.

Natural Humectant

Natural humectant – Hydrophilic (water loving) properties of honey make it a strong humectant.  As discussed honey has a low water content of around 18.8% however it will absorb water from the atmosphere of a relative humidity of 60%. This ability to draw in water, its hygroscopy can help keep the skin plump and moist.

 Microbes in honey

Although in its pure an natural state honey has many antibacterial properties, it also contains a number of micro organisms that remain  dormant in its undiluted state.  Many micro organisms can not survive in pure honey due to its hyperosmotic nature, which draws moisture away from the microbes, killing them.

Microorganisms that do survive  are those that can withstand the acidity, concentrated sugar, and other antimicrobial characters of honey. These microbes come from various sources – the environment and the bee itself.

”Microorganisms found in honey have been identified). They include bacteria, yeasts and moulds. Most bacteria and other microbes cannot grow or reproduce in honey i.e. they are dormant and this is due to antibacterial activity of honey. Various bacteria have been inoculated into aseptically collected honey held at 20°C. The result showed loss of bacterial viability within 8–24 days. It is only the spore forming microorganisms that can survive in honey at low temperature. The spore count remained the same 4 months after. Bacillus cereus, Clostridium perfringes and Clostridium botulinium spores were inoculated into honey and stored at 25°C. The Clostridium botulinum population did not change over a year at 4°C. At 65°C however, no spore were found after 5 days of storage. ”(White PB,  1996. pp. 301–309)

Honey in cosmetic products

Honey can be used in a variety of ways. You can use it on your face to cleans and exfoliate.  There are also many products on the market that contain pure honey. Lush has a self preserved shampoo and a soap and there are other honey containing creams and balms on the market.  You can also get powdered honey to use in completely dry products like bath bombs, bubble bars and cleansing powders.

Pure honey is water soluble so it can be put in the water phase of your product however it is not wise to dilute too much.  You either need to use very small amounts of honey, supporting it with a preservative, or use it in very high quantities so that it aids preservation of the whole formula.  It has been  observed that honey diltued to 50% supports growth of non- pathogenic (non human diseases forming) bacterial strains but kills the dangerous ones.(Gilliam M, Prest DB, 1987;49:70–75.)  That means that although honey diluted by half may not be harmful to humans it might cause the product to degrade and affect its overall stability.

**Image by Muhammad Mahdi Karim (www.micro2macro.net) Facebook Youtube – Own work, GFDL 1.2, https://commons.wikimedia.org/w/index.php?curid=6699147

Below is a selection of studies and reviews that have been done about honey and its antibacterial properties

Gilliam M, Prest DB. Microbiology of Lanial honey bee(Apis melifera) Jounal of Invertebrate Pathology. 1987;49:70–75.

White PB. The normal flora of the bee. Washinton AC: Agricultural research service. US Department of Agriculture; 1996. pp. 301–309

Cutis. 2004 Feb;73(2 Suppl):3-13. The use of polyhydroxy acids (PHAs) in photoaged skin. Grimes PE1, Green BA, Wildnauer RH, Edison BL.
Cutis. 2004 Feb;73(2 Suppl):14-7. A polyhydroxy acid skin care regimen provides antiaging effects comparable to an alpha-hydroxyacid regimen.
Antibacterial properties of monofloral honey – http://www.sciencedirect.com/science/article/pii/S0963996916300886
Review Biological properties and therapeutic activities of honey in wound healing: A narrative review and meta-analysis – http://www.sciencedirect.com/science/article/pii/S0965206X15000972
Biological properties and therapeutic activities of honey in wound healing: A narrative review and meta-analysis

Ahmad Oryan, Esmat Alemzadeh, Ali Moshiri

Journal of Tissue Viability. May 2016, Vol. 25, No. 2: 98-118
A systematic review and meta-analysis of dressings used for wound healing: the efficiency of honey compared to silver on burns

Terese Lindberg, Oscar Andersson, Molina Palm, Cecilia Fagerström

Contemporary Nurse. Apr 2016: 1-14
Effect of Tualang honey on the anastomotic wound healing in large bowel anastomosis in rats-A randomized controlled trial

Muhammad Izani Aznan, Omaid Hayat Khan, Allah Obhayo Unar, Sharifah Emilia Tuan Sharif, Amer Hayat Khan,Syed Hassan Syed Abd. Aziz, Andee Dzulkarnaen Zakaria

BMC Complementary and Alternative Medicine. Dec 2015, Vol. 16
Modeling the synergistic antibacterial effects of honey characteristics of different botanical origins from the Sahara Desert of Algeria

Hadda Laallam, Larbi Boughediri, Samia Bissati, Taha Menasria, Mohamed S. Mouzaoui, Soumia Hadjadj, Rokia Hammoudi, Haroun Chenchouni

Frontiers in Microbiology. Nov 2015, Vol. 6
Effects of honey on oral mucositis in patients with head and neck Cancer: A meta-analysis

Hye Kyung Cho, Yeon Min Jeong, Ho Seok Lee, Yeon Ji Lee, Se Hwan Hwang

The Laryngoscope. Sep 2015, Vol. 125, No. 10.1002/lary.v125.9: 2085-2092
Medicinal honey as treatment for skin reactions associated with bone-anchored hearing implant surgery

Erynne A. Faucett, Saranya Reghunathan, Abraham Jacob

In Part 1 of Preserving Botanical Formulations Naturally we introduced you to strategies used to preserve products. Now we will take a closer look at the hurdle approach which can be used in formulating natural and non-natural skin, hair and body care products.

 

HURDLE 1: GMP

Preservatives should not be added to negate any unclean manufacturing practices. (Dweck 2005) They are used to prevent any contamination after manufacture – there are bacteria in the air and carried on peoples skin so it is important to protect the product from any environmental and human contact.  In short, the product should be clean at the point of which the preservative is added Dweck (2005) states;

There is a common misconception among many manufacturers who use preservatives as a fail safe option due to poor plant hygiene and manufacturing systems. This strategy often fails miserably, resulting in many product recalls and contamination incidents due to the preservative system being overloaded and used up fighting contamination before the product has even left the manufacturing vessel.’’

So how do we ensure our products start off clean?
• If possible, test all raw materials to ensure they are clean (at minimum you need the certificate of analysis)
• Water used in products must be clean and screened or sterilised before use. You need to use deionised and/or purified water and if you can, make sure it is  pasteurised before use in a cold processed product.
• All equipment including pumps and valves need to be sterilised and if possible checked for contamination.
• There should be good procedures and processes in place to ensure that cleaning is carried out to a high standard
• Staff need to be trained on maintaining adequate personal hygiene and regular checks need to be carried out to ensure compliance to procedures and processes. (Dweck, 2005, Personal Care)

‘’We can protect cosmetics from contamination during manufacturing by strict enforcement of sanitation procedures. We should rigidly require and monitor cleanliness of process water, other raw materials and manufacturing processes, and maintain high standards of personal hygiene.’’ (5)

Another important part of GMP is having procedures in place to ensure your preservative has been included. There is no point having a great preservative system if the finished product does not contain it!   Many manufacturers ensure that two people are present to observe and record the preservative being added. (6)

Hurdle 2: pH

Using pH to control the growth of microbes work in a number of ways. Firstly, some pathogenic and product spoiling microbes do not survive at certain pH ranges. Secondly, some preservatives are more efficient within a certain pH range.

pH and Germ Survival

Normally when we talk about microorganisms we refer to bacteria and fungus (mould and yeast). There are many bugs that do not survive extreme pH ranges. Most microbes, and especially pathogenic ones, can survive and grow in a pH of between 5 and 8, so slightly acidic, neutral and slightly basic. Most bacteria prefer a neutral pH of between 6.5-7.5 and most gram positive and gram negative bacteria cannot survive below pH 4.5. However many pathogenic yeast and moulds can thrive in acidic pH levels below pH 4.5.

Most organisms die off at pH above 10. Traditional solid soap is probably the most common example of a product preserved by its pH. Soaps pH is normally around 9.5-10 which will not support the growth of most dangerous bacteria, yeast and mould. It also has a low amount of water which means that it has a few hurdles for micro-organisms to overcome.

Similarly, nearly all gram positive and negative bacteria are not able to survive acidic environments. Dropping the pH of a product to 4.7 will create an additional hurdle for bacteria. Dropping under 4.5 will eliminate most if not all harmful bacteria but will not kill yeast and mould. It is also known that as the pH falls below pH 3,0, the conditions for growth of yeast becomes hostel. (7)

There are of course organisms that survive extreme pH ranges. These are called extremophiles. These are organisms that can survive extreme environmental conditions. This could be extreme heat or extreme pH and even high salt/sugar levels. Acidophiles like Lactobacillus (the lactic acid producers) can live quite happily in very low pH ranges of 0.1-4.  On the opposite end of the spectrum there are Alkaliphilies, alkali loving organisms like Vibrio cholerge and Alkaligenes faecalis who love a high pH of 9. However, these extremophiles are not generally pathogenic to humans who are naturally of a neutral pH – our skin is between pH 4.7 and 5.4 , our saliva is about 7.4 and our blood is neutral – between pH 7.35-7.45. Part of the reason for them not being a threat to humans is because they do not like our pH so they will not live or multiply in us (8)

pH and preservatives

pH can also have an effect on the preservative efficacy and stability. For example, weak acids like sorbic and benzoic acid become increasingly more potent as the pH drops. The lower the pH, the more  undissociated the acid becomes, which has the biocidal effect; that which will kill harmful pathogens. (9)

A low pH can thus have a two-fold action, it can simultaneously kill many harmful bacteria as well as improve the efficiency of the preservative.

 

Hurdle 3. Water activity

All organisms need water and nutrients to survive. Limiting the available water is another strategy that can be used to help stop microbial growth.

Water activity/available water is not the same as the percentage of water in a product. Instead, it is normally used to refer to water that is not bound with solutes, particularly glycols, polyols or salts. By definition, if there is no water in a product, if it is non-aqueous/anhydrous then there is no available water. However, there can be no available water even if the product contains a fairly large amount of water. One good example of this would be honey which if it is to be defined as honey (and legally to be sold as such) contains about 20% water. Another example would be brine water used to preserve food – the water is tied up with the salt and is not available for cells to grow. So how much available water is needed for different organisms to survive?

In terms of available water, 1.00 would be 100% available water and 0.00 would be bone dry. The approximate amount of water needed for organisms to thrive are as follows;
Bacteria 0.94-0.99
Yeast 0.7
Mold 0.6

As Dweck (10) states, reducing available water, ” can be achieved by the addition of salts, polyols, sugars, protein hydrolysates and amino acids and is more effective in controlling gram-negative bacteria than yeast and moulds.’’

There have been cases where humectants have been used at sufficient levels alone to increase the formulas resistance to contamination. In a dental cream, a mixture of sorbitol and glycerine, at respective levels of 10% and 12%, is often enough to protect the formula. (Antibacterial Agents and Preservatives Franc¸oise Siquet, Colgate-Palmolive Technology Center, Milmort) Likewise, Dekker et al 1997) states that ‘Sorbitol and glycerol, in concentrations of around 20% w/w, are most commonly used to reduce water activity’’ (11)  Typically we would only need 20-35% glycerine in a product to effectively preserve it, however, this would probably make a very sticky product.

To measure water activity in a product special instruments are needed such as  vapour pressure manometry, electric hygrometry, hair hygrometry and dew point. However, testing water activity of finished formulations can be valuable in understanding what type of preservative to include, for instance, if it is found that only fungi can grow, only preservatives with activity against fungi need to be used.

It is probably important to note that although you cannot measure water activity, there are some formulations where you can be pretty certain do not need a preservative. For instance, there are a lot of salt sprays on the market that do not have preservatives. There are also products preserved with high amounts of ethanol (alcohol) which will not spoil i.e. >20%.

Hurdle 4. Packaging

How you package your products can have an impact on the type of preservative you use and even the amount of preservative you will need.

Packaging material and chemical reactions

It is thought that oil soluble preservatives can be absorbed into containers and closures. It is advised that products should be tested in their intended containers to determine the preservatives effectiveness under normal storage conditions because, ‘absorption, complexation, and volatility can erode antimicrobial activity….certain containers are not compatible with certain preservatives, such as nylon and parabens or polyethylene and certain phenolics, mercurial and benzoates.’ (12)

Packaging and consumer abuse

The main challenge, after manufacturing considerations, to the cleanliness of a product is how it is used by the consumer. Brannan and Dill highlighted that unpreserved shampoo bottles with a flip-top lid showed the highest degree of protection from contamination. With regards to lotions, pump top dispensers gave the greatest protection from contamination. They found that screw cap and slit caps provided the least amount of protection from consumer use and contamination. The study showed that the container is an intrinsic aspect in formulation and that preservation is not just about adding a preservative, but it is about the how the whole product functions and interacts with the container and the end user.(13, 14)

Hurdle 5. Type of formulation

The use of different formulation types can help and hinder preservation. For instance, if surfactants are present at levels above their critical micelle concentration (CMC) then they could lock around the preservative inhibiting its effectiveness. Conversely, if they are evident at a lesser level then they could help solubilise the preservative and have a detrimental effect on the cell wall of the organism (the germ), making it weak and  vulnerable to attack. (15)

EMULSION TYPES

Different types of emulsion are more susceptible to microbial growth. Typically water in oil emulsions are easier to preserve than oil in water emulsions.  This is because the water droplets are in the internal or dispersed phase, surrounded by oil (in the continuous phase) making it difficult for microbes to migrate into other water droplets.  Theoretically, bacteria and mould would be introduced in the manufacturing process but find it hard to migrate once there. Furthermore, the smaller the droplet and the more densely packed the emulsion the harder it is for germs to move around and multiply.  Some sources suggest that once the oil content of the emulsion reaches over 83%, it is very difficult for microbes to multiply and cause problems.    That doesn’t mean that it is impossible for them to grow so they may still need a preservative.  Due to all this, it is likely that it would need less preservative in a water in oil emulsion as opposed to the oil in water type.

CATIONIC SURFACTANTS

Many cationic surfactants are very effective, however some are classified as preservatives and have very low permitted levels as they can be irritating and cause sensitisation (16).

Hurdle 6. Using multifunctional anti-microbial ingredients

Using other ingredients not classified as preservatives

You can create a ‘preservative free’ or ‘self-preserving’ product by using actives and ingredients that have secondary preserving benefit.  There are a number of ‘multifunctional’ agents that are based on or marketed as humectants, fragrance materials, conditioners, antioxidants (to name a few) that are that are not officially classified as preservatives under the EU Directive.  Although they are not classified as preservatives, they do have preserving qualities to them that could be considered just as powerful as more traditional types of preservation i.e. phenethyl alcohol (fragrance found in rose oil) or propanediol (humectant), glyceryl caprylate and levulinic acid and its salts are a few. Sodium lauroyl lactylate is not only a detergent/surfactant, at 0.5% it can be used to significantly decrease the anti-fungal activity of the overall formulation. (17)

Using chelating agents to support your preservative 

Metal ions are normally found in water and raw materials. They are also an important part of the cells of all living organisms including bacteria and fungus. However, they can have negative effects on a cosmetic formulation. They can cause chemical degradation, discolouration, emulsion instability, rancidity, changes in fragrance and all sorts of other problems which can impact on the shelf life of the product and manufacturing processes.

Chelating agents have an effect on micro-organisms and can work with the preservative in order to make them more efficient. Metals such as Ca and Mg are very important for stabilising the outer membrane of cellular organisms like bacteria and fungi. They are part of the building blocks that make up their cell wall. Chelating agents (also referred to as sequestering agents) tie up metal ions, pulling them away from the cell by forming complexes. This contributes to the cells wall being weakened or to ‘partial solubization of the cell membrane’ which allows preservatives (biocides) a way in, causing it to die. (18,19)

Preservatives on the market

Typically preservatives on the market are blends, whether they are designed for the natural market, whether they are legally classified as preservatives; or whether they are multifunctional actives with microbial actions. Preservatives are normally in blends because they work to provide a wide coverage against fungi and bacteria. By working together they work synergistically so typically less is needed for each preservative in the blend, using less of each individual preservative means less likelihood of irritation.

The Myth about mild preservatives

I keep hearing that ‘natural preservatives’ are not as efficient as the traditional paraben based or formaldehyde donor types of preservatives. Essentially, it does not matter how you preserve your formula as long as you ensure it is safe. Whether a preservative works has no bearing on whether it came from a natural source or not – its effectiveness at keeping your product clean and it’s rate of irritation are what is important. Some preservatives have a higher use rate to work than others. So you have preservatives that are effective at killing at 0.1% and those that are effective at 0.5 and now, there are newer blends on the market where you might need 3 or 4 %. I think Dene Godfrey summed it up perfectly when he said;

 

‘’ The concept of a “mild” preservative is based on the compound having a good toxicity profile, especially regarding skin irritation/sensitisation. In other words, a higher concentration of the “mild” preservative is required to elicit an adverse reaction. To illustrate this, parabens are considered to be relatively mild preservatives, whereas the isothiazolinones are not. This is reflected in the use concentrations; parabens are required at concentrations varying from 0.2 – 0.4%; isothiazolinones from 5 – 15 parts per million (0.0005 – 0.0015%)…The difference in the margin of safety between an “aggressive” preservative at 0.0005% and a more “mild” preservative at 1% is very little, as the end result is a concentration high enough to exhibit biological activity – killing micro-organisms! ‘’ (20)

Predicting the efficacy of your preservative

Every formulation is different and just because you have used a preservative successfully in one type of formulation, does not mean that it will work in another. This is because it is impossible to know how it will interact with both the microorganism, the formula and the packaging. So, in order to know if your preservative works and that your product is safe, you will need the assurance of a preservative efficacy test on each and every formulation. It doesn’t matter if you use a tried or tested preservative, like the traditional paraben blend, or a new one such as Geogard ECT or one that is considered ‘natural’, they all need to be tested in every product you bring to market. Furthermore, advice can be given on the best preservative that can be used but this still does not negate the need for thorough testing.

Selecting a preservative for your botanical formulation

It can be a bit tricky selecting the right preservative but thankfully there are many small-scale suppliers that sell preservatives acceptable to the organic market. They will normally give detailed information on how to incorporate your preservative. Having said this, it is a good idea to seek out the manufacturer’s advice.  You can do this easily by googling the INCI of the product or the brand/manufacturers assigned name and adding ‘PDF’ to your search. Once you have the information they will tell you some important things about your preservative, mainly;

  1. How wonderful it is
  2. The pH you need to add it at – most of them require an effective pH range – this is important. Most will require a pH of 5.5 or less. In which case you need to cross-reference with your other ingredients. Interestingly many natural emulsifiers do not work well under pH 6 which can be a problem, in which case you will need to experiment more. It might be okay but you may need to support your emulsifier with additional fatty acids or another emulsifier. You may need to change your emulsifier entirely.
  3. They may say that it is ‘broad spectrum’. This may be true but if you read carefully they may hint that it is ‘weak’ with certain germs in which case you would need to consider how you will tackle it’s deficiencies.
  4. The phase in manufacturing you need to add it – the supplier could say that it needs to be added to the cool-down phase. They may also say that it could be added up to 80c with no problem. It is ideal to put your preservative in the water phase and heat it but it may not work out well with your formula. It is worthwhile testing to see if adding at different phases could have an effect on stability or aesthetics.
  5. What it is compatible with and what it doesn’t agree with – if the incompatibility is due to safety reasons or the preservatives performance then follow the advice.  But if it is to do with aesthetics it might be worthwhile trying it to see how it affects the overall formula if added at different phases of manufacturing.
  6. The percentage range to use. For instance, a manufacturer could advise to add it between 0.8-1.2% of the overall formula. Ideally, it is better to add it at the lowest percentage rate and test however if you do not have the luxury of infinite testing it is probably better to start mid range – again you must test.

Selecting a preservative and testing can be problematic. But when you know what you are doing and you experiment it is far better than being spoon-fed information. I have chosen not to give percentage rates of different preservatives as they are readily available online by manufacturers along with their advice which I feel is the better way to go.  Also, it doesn’t give a false sense of security, helps you understand what you are doing and why you are doing it.

REFERENCES:

1. Ayliffe et al 1966 in Hiom, 2008, Chapter 14. Preservation of Medicines and Cosmetics).
2. W. Siegert, 2012 Microbiological Quality Management for the Production of Cosmetics and Detergents
3. S. Hiom, 2008
4. Kabara, Jon J., 1999, HURDLE TECHNOLOGY: ARE BIOCIDES ALWAYS NECESSARY FOR PRODUCT PROTECTION?
5. Janet C. Curry, Daniel K. Brannan, with Philip A. Geis, 2006 History of cosmetic microbiology in cosmetic Microbiology: A practical approach
6. W. Siegert Microbiological Quality Management for the Production of Cosmetics and Detergents, SOWF, 2012
7. PITT, J.I., Resistance of some food spoilage yeasts to preservatives, Food Technology, 26(6), pp. 238, 239, 241, 1975)
8. Int J Cosmet Sci. 2006 Oct;28(5):359-70. doi: 10.1111/j.1467-2494.2006.00344.x.Natural skin surface pH is on average below 5, which is beneficial for its resident flora.Lambers H1, Piessens S, Bloem A, Pronk H, Finkel P
9. Eklund 1989 in R.J. Lambert and M. Stratford Microbiology Section, Unilever Research, Sharnbrook, Bedford UK, journal of microbiology
10. http://www.creative-developments.co.uk/papers/Preservatives%20SPC%202000.htm
11. KABARA, J.J. and ORTH, D.S., Principles for product preservation in preservative-free and self preserving cosmetics and drugs, Marcel Dekker, New York, pp. 1-14, 1997).
12. Scott, V.W. Sutton, 2006 Antimicrobial preservative efficacy and microbial content testing in Cosmetic Microbiology: A practical approach.
13. j. Soc. Cosmet. Chem., 46, 199-220 (July/August 1995) Cosmetic preservation DANIEL K. BRANNAN, Department of Biology, Abilene Christian University, Abilene, TX 79699. Received February I995.
14. Geis, 2006, Preservations Strategies in Cosmetic Microbiology: A practical approach
15. http://www.creative-developments.co.uk/papers/Preservatives%20SPC%202000.htm
16. http://www.creative-developments.co.uk/papers/Preservatives%20SPC%202000.htm
17. Belgium Michel J. Devleeschouwer, Free University of Brussels, Brussels, Belgium, 2001
18. W. Siegert* Boosting the Antimicrobial Efficiency of Multifunctional Additives by Chelating Agents) Typically EDTA is used for this purpose in cosmetics however there are other alternatives.
19. Kabara, J.J Preservative-Free and Self-Preserving Cosmetics and Drugs: Principles and…, Handbook of Cosmetic Microbiology).
20. http://personalcaretruth.com/2010/12/mild-preservatives-fact-or-fiction/

USEFUL WEBSITES:
If you want to learn about some of the germs you are wanting to kill, hop on over to  MICROBIOLOGY ONLINE  where you will get lots of great information.

INTRODUCTION – Preserving Botanical Formulations

Preservatives are needed in cosmetic products for two reason. Firstly, to protect it from spoilage and; secondly to protect the consumer from being infected by a contaminated product.

Preserving botanical formulations naturally  can be quite a challenge. Since the demonisation, bans and restrictions on some commonly used preservatives, scientists have had to think creatively about how they preserve cosmetics.  As a result there has been growing interest in preservative free and self-preserving methods.

Self preserving cosmetics normally refers to products that have anti-microbial agents that are not listed under the Annex VI of the EU Directive. These types of ingredients are normally classified as skin conditioning agents or fragrance materials. They also refer to strategies used to create a series of hurdles which limit growth of pathogenic or product spoiling organisms.

Inventors of new preservative blends have to think outside the box when coming up with new and effective blends of antimicrobial ingredients that will satisfy buyer demands as well as be practical and easy to use.

Formulators also have to think more carefully about how they include these preservatives as some can compromise the formula i.e. cause destabilisation (separation or thinning of emulsions), change in colour, pH or scent. Many preservatives are based on blends of organic acids or alcohols which require a lower pH to be effective. This will obviously have a bearing on the other ingredients in the formula.

The following post is a basic guide to strategies that can be employed to preserving botanical formulations. A combination of using preservativesaccepted by most organic standards as well as the hurdle approach are normally enough to make something that is safe and virtuous to use and sell!

Why is preservation important and why should we care about germs?

preserving botanical formulations

A preservative can be defined as ‘A chemical agent that will either kill or inhibit the growth of microorganisms’

As stated above preservatives are used to protect the product from spoilage and also to protect the consumer from infection. There have been a documented cases of product contamination leading to serious illness and death. In the 1950’s there was a case of newborn babies contracting tetanus from contaminated talc. Similarly, in the 1960’s severe eye infections were linked to the inappropriate preservation of eye drops (1). For these reasons pathogens of concern, especially for the eye area include Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa and other Pseudomonas species also Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans.  These are thought to be the main pathogens likely to contaminate cosmetic products and cause harm.(2)

The cosmetic product is the perfect breeding ground for bacteria and fungi as S. Holm states;

”The nutritional requirements of most saprophytic non-fastidious spoilage contaminants are likely to be well met in almost all pharmaceuticals and cosmetics, since many ingredients are easily biodegradable, and even the trace residues of nonspecific chemical contaminants present in most commercial ingredients are likely to provide ample nutrients to permit growth. For example, even standard distilled and demineralized water contains sufficient trace nutrients to permit ample growth of pseudomonads and related species (Favero et al., 1971). It is usually the physicochemical [characteristics] parameters of the formulation which are the determining factors as growth will or will not take place’’(3)

USING THE HURDLE APPROACH

Hurdle technology or the hurdle approach has been used in the food industry since the 1970’s, and describes the use of different strategies to limit the things needed to support microbial growth. So what do microbes need to multiply to unsafe levels?

For growth, micro organisms need the following to thrive:
– Water
– Source of energy (food)
– Source of nitrogen
– Vitamins & related growth factors
– Minerals/heavy metals

Hurdle technology provides a number of challenges (hurdles) that the microbes are not able to overcome (jump over). This includes:
• Good manufacturing practice (GMP),
• pH control
• type of emulsion
• using multi-functional antimicrobial ingredients
• water activity and water content
• packaging.

The idea is that by creating a difficult environment for the organism to survive, you will eventually cause it to becoming inactive and unable to multiply/grow. These hurdles can mean that less or even no preservative is needed. (4)

In Preserving Botanical Formulations Naturally – Part 2 we will take a closer look at the hurdle approach.

This is an approximate dupe of Lush’s Showder called Candy Floss.  Lush Showder’s are basically deconstructed bath bombs with some surfactant to clean. I am not sure of the scent as I have not used this product so it is a guess but after making it I like the results.  It foams nicely but not too much and it bubbles up well.  I must admit I am a fan of Lush because they are fun and are not scared to try something different. Showder’s are definitely that!

Calamine powder is zinc oxide with about 0.05% iron oxide. It is soothing and aids healing and that is why it is found in many a healing balm.  It is also a lovely pink colour which adds a bit of interest. When water is added to this powder, the reaction between the citric acid and sodium bicarbonate cause it to foam and the SCI then helps it bubble.

 

BODY SHERBET (Because it smells of Sherbet)

showder

INCI: Sodium bicarbonate, cornstarch, calamine, citric acid, sodium cocoyl isethionate, Vanilla Planifolia Fruit (or)Vanilla Tahitensis Fruit oil, Canaga odorata (Ylang Ylang) flower oil, Eugenia Caryophyllus (Clove) Flower Oil

INGREDIENTS YOU WILL NEED:

  1. 30g Sodium bicarbonate
  2. 15g citric acid
  3. 20g calamine powder
  4. 15g sodium cocoyl isethionate
  5. 19g cornstarch
  6. 0.5g vanilla absolute
  7. 0.3g ylang ylang
  8. 0.2 clove oil

METHOD:

  1. Wear a dust mask
  2. Weight each ingredient and then stir gently

NB – You may want to mix the essential oils together and add them to a small amount of the cornstarch and then add to the rest of the formula.

You can also change the surfactant to another one or a blend but make sure you keep within safe limits and adjust accordingly (replacing any reduction or increase in the surfactant with cornstarch).

THE SUGAR VERSION

INCI: Sodium bicarbonate, sucrose, cornstarch, calamine, citric acid, sodium cocoyl isethionate, Vanilla Planifolia Fruit (or)Vanilla Tahitensis Fruit oil, Canaga odorata (Ylang Ylang) flower oil, Eugenia Caryophyllus (Clove) Flower Oil

  1. 23.75g Sodium bicarbonate
  2. 23.35g granulated sugar
  3. 11.60g citric acid
  4. 15g calamine powder
  5. 11.60g sodium cocoyl isethionate
  6. 14.70g cornstarch
  7. 0.5g vanilla absolute
  8. 0.3g ylang ylang
  9. 0.2 clove oil

People are worried about failure in this industry,  I see it in the sphere of home crafting cosmetics anyway. There seems to be a culture of people not practising and experimenting enough with ingredients for fear of not getting things right straight away. They may also fear wasting ingredients.  The thing is, if you are not in a position to get free samples then this is one of the things you have to deal with or you will never really learn the art.

Yes, you can learn from others mistakes but you have to remember two things;

(a) to get to where they are they have spent a lot of their time and money learning and;

(b)  Until you do it yourself, it is still just theory.

For me lack of experimentation and fear of failure is a problem because in cosmetic formulating and in life, experimenting is the one thing that has to happen for learning and growth. These things have to happen for you to ultimately make fantastic products. I see that people want answers straight away and want to get it right instantly.  But this is impossible, especially if you have only just started on your journey. Experimenting is also important for even the most experienced of cosmetic scientists. New materials are coming out all the time so it is important to play around with these ingredients to see how they behave.

My experience

When I first wanted to bring a selection of soaps to market I had just started on my cold-processed soap journey and was enjoying myself. Soap making is truly a satisfying hobby. But initially I was disappointed, many a safety assessor would not agree to sign off a cold processed soap product unless I had a minimum of one year experience in soap making. Could I wait that long I thought? But the choice wasn’t there and I was already obsessed with soap.

It took me another two years of experimenting and deciding how I wanted my soaps to be, before I presented my formulations to my safety assessor. In hindsight I am glad it did. All sorts of things happened in that two year journey. I realised a number of lessons to do with the art and chemistry of soaping, I also realised that all the so-called ‘failures’ and successes in my journey gave me the experience I needed to work effectively and safely in soap making.

It taught me how the ingredients interacted and gave me intimate knowledge of the aesthetic characteristics of the raw materials in relation to the end soapy product. I have had all sorts of things happen – I have had soaps rice, become like a volcano, separate and then magically come back together again.  I learnt some important lessons about how fragrance and colour interacts with soap batter and how to change my processes to account for them. These are just a few things. Soap can be extremely unpredictable and even now formulas that I have worked with umpteen times can prove to cause a problem for no apparent reason, somewhat randomly.  Reading books about soaping have given me a great foundation;  don’t get me wrong,  until you make a soap it is merely conjecture. Only experience has given me this knowledge and this knowledge takes the anxiety away when things do go awry. As a result I have learnt to just relax and enjoy the quirks and foibles of soap.

Why it is important to practise your art

Now, soap making is just one journey but it can be transposed onto any other type of cosmetic product development and indeed any other kind of occupation. Essentially, I am talking about the importance of experience. For me experience is just about being around long enough to make lots of mistakes and to have lots of triumphs and to learn from both.  As long as you ask ‘what went wrong and why?’ it is all for good gain.

Experience is not something you can learn in books. Theory is theory, books are great and the written word can teach us many useful things but ultimately practise is what will make you a great formulator.    As you experiment with more materials, as you learn your art, as you experience more, you will find that in the end  formulating is almost intuitive. You will find that as you work with more materials, you will have less hiccups, less time spent on wondering what went wrong and have more formulations turn out exactly how you envisaged they would.

Rebecca xoxo

So this morning I woke up and decided that I was going to make an exfoliating cleansing powder that was gentle and totally natural. Cleansing grains have become quite popular as they are very gentle and easy to use. This is my recipe but you can play around with the ingredients to suit your taste.

2% Calendula Petals

4% Chamomile petals

4% Lavender Petals

20% Rice powder or flour

50% Oats

20% Almonds

Remember to weigh your ingredients (I use grams) so you have accuracy.

There appears to be some confusion about whether or not an anhydrous SUGAR/SALT scrub needs a preservative.  I have brought a fair few products to market that do not contain water.  These range from lip balms, face and body balms to anhydrous sugar and salt scrubs and none of these have required a conventional  preservative or a preservative efficacy test (PET) under EU law.  I have also looked at the market and noticed many anhydrous products on the market that do not contain preservatives – these are from both big and small cosmetic companies.

I have visited and consulted with a number of microbiologists that perform PETs that do not push micro testing or preservatives in many anhydrous products.  So when I read on some sites quoting microbiologists that an unpreserved anhydrous sugar/salt scrub is UNSAFE I was surprised and mystified!

This post is going to look at the reasoning behind PETs, touch on current EU legislation and practical considerations when deciding whether a preservative in your anhydrous sugar or salt scrub is necessary or even effective.

What are the arguments for using a preservative?

I understand the rationale behind why a preservative should be used on a product that could come into contact with moisture.  The idea is that when you are in the shower and you use a sugar scrub, water is likely to get into the container.  Water along with sources of energy and heat are the conditions for bacteria, yeast and mould to grow, so it would make sense that a preservative is needed.  These scientists argue that the preservative should be a traditional water soluble one so that when water gets into the scrub it will cross over into the water quotient and protect it.  No mention is made by the same scientists about other things within a product which could help protect it.

But is it practical and does it actually make the product any safer than if it simply contained no preservative?  In my view, and in the view of many highly qualified safety assessors (including clinical pharmacologists who consider the entire safety profile of the product, not just its microbiology aspect) it does not.

So how do formulators and safety assessors determine whether a product needs a preservative or a preservative efficacy test?  What governs the decision making process? How do the professionals determine whether an aqueous and non-aqueous product is safe?

The EU has some very specific guidelines and legislation around cosmetics products set out in the EU Cosmetics Directive. This directive is based and informed by the knowledge of chemists, microbiologists and other specialists in the field who make up the Scientific Committee for cosmetic products.

In the EU it is compulsory to have a safety assessment which will also include preservatives efficacy testing if indicated.  The ‘suitably qualified’ safety assessor has to justify every decision they make in a Cosmetic Product Safety Report and their guidance specifically refers to different International Organisation of Standards (ISO) for different areas of testing.  The ISO are internationally recognised minimum standards which set out guidelines for good manufacturing practice, guidelines for performing preservative efficacy tests  for different pathogens and risk assessments for identifying low risk products that do not need preservative efficacy testing (ISO 92621).   They will also look to COLIPA: Guideline for Microbiological Quality Management (MQM).

Similarly in the U.S a chemist will use or adapt the same ISO’s and also use the United States Pharmacopoeia.  The idea of having this standardise basic guideline is to make trade between countries more, let us say, standard.  If everyone has the same basic commonly accepted testing methods then there should be no need for additional testing which could halt or delay trade.

EU Legislation

When deciding on whether a preservative is needed the chemist/safety assessor will (a) look at the composition of the product (b) look how it is likely to be used under normal conditions and (c) use industry guidance such as ISO, USP and EU Directives and guidance. They will also look at things like duration of contact of the product on the skin and concomitantly exposure rates.  Altogether there are 10 different aspects to the report but they are not all relevant here.

Let us look at this in relation to the above:

  • What is the composition of an anhydrous salt and sugar scrub and its physical characteristics?

A salt/sugar scrub will contain high amounts of salt or sugar (>60% probably), will have oils, butters and maybe waxes.  May or may not contain an emulsifier and will probably have some kind of fragrance/essential oil blend. We can assume that each ingredient is 99-100% pure and the toxicological profile for each ingredient is sound based on the INCI and certificate of analysis.

  • How it is likely to be used.

EU legislation states that;

‘Cosmetic products should be safe under normal or reasonably foreseeable conditions of use. In particular, a risk benefit reasoning should not justify a risk to human health.’

So what does this mean?  When determining how to safety assess the product the assessor has to consider how it is supposed to be used.  Normal use would be that as a scrub it is going to be used in the shower or bath on damp skin, rubbed on the skin and then showered/washed off within a matter of minutes.  Is it reasonable to expect that some water is going to get in there? Yes, I would say so – water will drip from the hands into the container.  Is it reasonable for the container to get completely flooded with water?  Probably not; it would not be pleasant, generally unsightly and most of the salt/sugar would dissolve.  So under normal and reasonably foreseeable use the product is going to only be in contact with the skin for a short while and will only be subject to  a small amount of water.  Working from these assumptions we could probably say that our salt or sugar solution left over by the drips of water is going to create a self-preserving product. 

C.  Does it need a preservative?

With regards to whether a product needs a preservative efficacy test, the safety assessor may look at different levels of guidance to support their justification.  In the EU they will probably look to the Guideline for Microbiological Quality Management (MQM) and ISO 29621:2010 standard “Cosmetics — Microbiology — Guidelines for the risk assessment and identification of microbiologically low-risk products’’.  The former is specific to the EU and the latter is an international standard that came into effect in 2010.

ISO 29621 – This document (used in most countries) helps identify low risk products that do not require preservative efficacy testing.  Such things as pH of the product, active water (water available for microbes to survive), high alcohol content (>20%), pour temperature and the use of different materials which will inhibit (or be a hurdle to ) the growth of micro-organisms are all taken into account (either in combination or separately) in deciding whether a cosmetic is low or high risk and concomitantly whether a PET is necessary.  What is significant to my argument is the ‘water activity’ of the product.  The rationale is summed up as follows;

“The water activity (aw) describes the amount of biologically available water within cosmetic formulations and is determined by comparing the vapour pressure of the formula containing water with the vapour pressure of pure water. Water activity may be reduced by the use of water binding substances, such as salts, polyols, protein hydrolysates, amino acids and hydrocolloids . Different classes of microorganisms have different tolerance to low water activity; bacteria generally have higher water requirements than yeasts, and yeasts higher requirements than molds. Gram-negative bacteria show more susceptibility to low aw values than gram-positive. Sorbitol and glycerol, in concentrations of around 20% w/w, are most commonly used to reduce water activity’’ ( KABARA, J.J. and ORTH, D.S., Principles for product preservation in preservative-free and self preserving cosmetics and drugs, Marcel Dekker, New York, pp. 1-14, 1997)

So, if we follow on from above, an anhydrous sugar/salt scrub will generally start off with low water activity as it does not contain water (or only trace amounts). If it does come into contact with water, which is very likely, what will be created is a salt or sugar solution which is likely to create an environment non-conducive to microbial growth.  How can we know that the solution that is created is strong enough to inhibit growth?   The answer is that we cannot know for certain as we cannot predict exactly how much water will go in there –  But we can operate under the presumption that the end user will use the product sensibly and how it is supposed to be used ‘under normal, reasonably foreseeable conditions of use’  Similarly, we cannot be certain the amount of water will not be too much of a burden on a conventionally preserved product.

Below is a summary of low risk products that do NOT require preservative efficacy testing.  Taken from ISO 29621: 2010.

iso-29621

 

Source: ISO 29621: 2010

( d) Duration of contact and exposure rates 

Let’s consider that the product is contaminated (usually by mould  – as that needs the least amount of water to grow) A scrub is not likely to be on the skin for very long as it will be washed off almost instantly by the shower or bath.  As such the risk is minimum because the exposure is minimum.   But let’s face it, if it is mouldy then it is not likely to be used!  (yes and I do know you cannot see bacteria) 

Things to consider when using a preservative: 

Let’s say that you have an anhydrous sugar scrub that contains a preservative.   There should only be enough preservative in the product to protect the product for the duration of the life of the product under normal use.  This means that it is not reasonable to expect that it will be used other than how it is marketed.  So we know it will not be used as a facial moisturiser or a body cream as that is certainly not reasonable or normal when it is marketed as a body scrub.  Let’s also hope people follow the directions.

Preservatives are potent chemicals which have a specific safe use rate – It is dangerous to use more than is recommended and you cannot use more to cover any extra water coming into the container.  A safety assessor will not pass your product if there is more than the legal safe limit.  If the scrub is used in the shower or bath and if water gets into the container will it have enough preservative to cover the extra water?  Will it be more or less effective than sugar or salt?  Again, that is uncertain.  

The hidden preservative 

There is also an argument that the product that contains ‘parfum’ have a hidden preservative.  These antimicrobial agents are often marketed as fragrance materials or skin conditioning agents (phenethyl  alcohol, sodium anisate, p-anisic acid, sodium levulinate etc).  Officially they do not fall under the EU list for acceptable preservatives in the directive so are not classified as preservatives but have antimicrobial activity which makes them a preservative (in the real sense).  However, to say ‘it has a hidden preservative’ simply because it has the word ‘parfum’ is not an argument as it is not categorically proven that this is the case.

If a sugar scrub needs a preservative then why not a lip or skin balm?

If we are to believe that an anhydrous sugar/salt scrub needs a preservative then what about other anhydrous products that could come into contact with moisture?  If we follow the pro-preservative-in-scrubs logic then we have to consider that all products that come into contact with moisture – regardless of whether they are in the shower or not –  need a preservative.  Lipsticks and lip balms are in contact with lips and saliva which contain micro-organisms that can multiply. Often we have high levels of humidity in the atmosphere yet, a preservative in other anhydrous products are not considered to be a high risk.  Why is this? What makes these products different?   To me, the fact that there is a risk of moisture means that the same should apply, yet it does not: at least not in the minds of some experts.

So to summarise;

  1. The sugar or salt solution is probably going to be enough to counter any bacteria, yeast and mould if only a limited amount of water gets into the container (under normal and reasonable use) but will probably not cover much more water than that.
  2. Similarly, if you use a preservative it will only cover a tiny bit of water getting into the pot and will not protect the product if too much water gets in there.
  3. The current advice given in ISO 29621 is that anhydrous products are low risk and it does not distinguish between those in contact with water and those that are not.
  4. Whether there is a need for a preservative is dependent on many factors and it is very formula dependent.  Does it contain water? Does it have high levels of glycols, salt or sugar? What type of container is it in? Are there botanical’s or anything else that can be additional sources of pathogens?  Are there any essential oils that can contribute to preservation?   Essentially we can not give a blanket answer to the question of preservatives with out asking these sorts of questions.

FINAL WORD

Ultimately it is your business and you need to do what is right for you so if you want to use a preservative  in this type of product, go ahead and use one. I suppose the extra help couldn’t do any harm.  My only advice would be to research independently, look at journals and other publications and follow the advice from people that are objective.

FINAL, FINAL WORD

Below is a selection of products on the market, some from large well established companies and some from lesser well known enterprises.  Some have no traditional preservatives and some have oil soluble preservatives,  (which goes against the advice to use a water soluble one).   And, for the sake of argument – you cannot class anything that creates a ‘hurdle’ as a preservative!!!

  • The Body Shop Spa Wisdom Africa Ximenia & Salt Scrub

Glycerin (Humectant), Sodium Chloride (Viscosity Modifier), Beeswax (Emulsifier/Emollient), Cetearyl Alcohol (Emulsifier), Disodium Lauryl Sulfosuccinate (Surfactant), Sodium Cocoyl Isethionate (Surfactant), Zea Mays (Corn) Starch (Absorbent/Chelating Agent), Butyrospermum Parkii (Shea Butter) (Skin-Conditioning Agent/Emollient), Fragrance (Fragrance), Cocamidopropyl Betaine (Surfactant), Hydrogenated Castor Oil (Emollient), Water (Solvent/Diluent), Ximenia Americana Seed Oil (Emollient), Hexyl Cinnamal (Fragrance Ingredient), Butylphenyl Methylpropional (Fragrance Ingredient), Limonene (Fragrance Ingredient), Benzyl Salicylate (Fragrance Ingredient), Alpha-Isomethyl Ionone (Fragrance Ingredient), Titanium Dioxide (Colour)

PRESERVATIVE: NONE.  There is a high amount of glycerin, lots of detergents, there could be a ‘hidden’ preservative but that can not be a given. For the sake of this arguement there is no traditional preservative.

  • REN Moroccan Rose Otto Sugar Body Polish

Saccharum Officinarum (Sugar), Prunus Amygdalus Dulcis (Sweet Almond) Oil, Olea Europaea (Olive) Fruit Oil, Glyceryl Stearate, Carthamus Tinctorius (Safflower) Seed Oil, Parfum* (Fragrance), Rosa Damascena Flower Oil, Cymbopogon Martini Oil, Pelargonium Graveolens Flower Oil, Geraniol, Linalool, Citronellol, Ilex Paraguariensis (Paraguay Tea) Leaf Extract, Cola Acuminata (Kola Nut) Seed Extract, Coco Glucoside, Tocopherol

PRESERVATIVE: NONE

  • Lush Rub Rub Rub

Fine Sea Salt (Fine Sea Salt), Sodium Laureth Sulfate (Sodium Laureth Sulfate), Fresh Organic Lemon Juice (Citrus limonum), Water (Aqua), Sodium Cocoamphoacetate (Sodium Cocoamphoacetate), Jasmine Flower Infusion (Jasminum officinale), Mimosa Absolute (Acacia decurrens), Orange Flower Absolute (Citrus aurantium amara), Jasmine Absolute (Jasminum grandiflorum), Lemon Oil (Citrus limonum), Lactic Acid (Lactic Acid), Lauryl Betaine (Lauryl Betaine), *Limonene (*Limonene), Perfume (Perfume), Colour 42090 (Colour 42090), Colour 45410 (Colour 45410)

PRESERVATIVE: NONE

  • The Body Shop Camomile Cleansing Butter

Ethylhexyl Palmitate (Skin Conditioning Agent), Synthetic Wax (Binder/Emollient), PEG-20 Glyceryl Triisostearate (Skin Conditioning Agent), Olea Europaea Fruit Oil/Olea Europaea (Olive) Fruit Oil (Emollient), Butyrospermum Parkii Butter/Butyrospermum Parkii (Shea) Butter (Skin Conditioning Agent – Emollient), Caprylyl Glycol (Skin Conditioning Agent), Tocopherol (Antioxidant), Parfum/Fragrance (Fragrance), Aqua/Water (Solvent/Diluent), Linalool (Fragrance Ingredient), Limonene (Fragrance Ingredient), Helianthus Annuus Seed Oil/Helianthus Annuus (Sunflower) Seed Oil (Emollient), Anthemis Nobilis Flower Extract (Natural Additive), Citric Acid (pH Adjuster).

PRESERVATIVE: NONE (although glycols can preserve, limonene helps and the pH is probably low – it contains a small amount of water).  There could be a hidden preservative in this under ‘parfum’ that can not be guaranteed.

  • Suki Foaming Facial Cleanser

Sucrose, potassium cocoate (saponified coconut oil)†, oryza sativa (rice) flour†, cymbopogon flexuosus (lemongrass) oil, avena sativa (colloidal oat) kernel flour, citrus aurantifolia (lime) peel oil, citrus aurantium dulcis (sweet orange) peel extract, squalane, chamomilla recutita (matricaria) flower/leaf extract, calendula officinalis (calendula) flower extract, lavandula angustifolia (lavender) flower extract, carthamus tinctorius (safflower) seed oil, olea europa (olive) fruit oil, ascophyllum nodosum (seaweed) extract†, fragrance (parfum)*, limonene*, citral*.
*components of 100% pure natural fragrance and/or steam-distilled/cold-pressed essential oils.

PRESERVATIVE: NONE

LIST OF ANHYDROUS PRODUCTS WITH A NON-BROAD SPECTRUM PRESERVATIVE NOT PROTECTIVE AGAINST MOULDS

  • Soap and Glory Sugar Crush Body Scrub

Glycerin, Maris sal (Sea salt), Sucrose, Polysorbate 20, Glyceryl stearate, Butylene glycol, Sodium chloride, PEG-100 stearate, Caprylic/capric triglyceride, Prunus amygdalus dulcis (Sweet almond) oil, Macadamia integrifolia shell powder, Citrus aurantifolia (Lime) oil, Dioctyl Adipate, Parfum (Fragrance), Benzyl alcohol, Ricinus communis (Castor) seed oil, Stearalkonium hectorite, Talc, Propylene carbonate, Propylene glycol, BHA, Propyl gallate, Limonene, Linalool, Citral, Citric acid, CI 77492 (Iron oxides), CI 77499 (Iron oxides), CI 77491 (Iron oxides).

PRESERVATIVE:  BENZYL ALCOHOL (PARTIALLY WATER SOLUBLE)

  • REN Rosa Centifolia™ No.1 Purity Cleansing Balm

Prunus Amygdalus Dulcis (Sweet Almond) Oil, Cetearyl Ethylhexanoate, Glyceryl Cocoate, Caprylic/Capric Triglyceride, Glyceryl Stearate, Glyceryl Dibehenate, Tribehenin, Glyceryl Behenate, Butyrospermum Parkii (Shea Butter), Sodium Cocoyl Glutamate, Parfum (Fragrance), Rosa Centifolia Flower Extract, Cymbopogon Martini Oil, Viola Odorata Extract, Anthemis Nobilis (Chamomile) Flower Oil, Lecithin, Benzyl Alcohol, Oryzanol, Tocopherol, Citronellol, Geraniol, Eugenol, Linalool

PRESERVATIVE: BENZYL ALCOHOL

  • Eve Lom Cleanser

Paraffinum Liquidum (Mineral Oil), Peg-30 Lanolin, Cetearyl Alcohol, Bis-Diglyceryl Polyacyladipate-2, Aluminum Stearate, Theobroma Cacao (Cocoa) Seed Butter, Peg-75 Lanolin, Phenoxyethanol, Eugenia Caryophyllus (Clove) Leaf Oil, Humulus Lupulus (Hops) Oil, Chamomilla Recutita (Matricaria) Flower Oil, Eucalyptus Globulus Leaf Oil, Bht

PRESERVATIVE: PHENOXYETHANOL (OIL SOLUBLE)

  • Boots Botanics Superbalm

Olea europaea (Olive) fruit oil*, Prunus amygdalus dulcis (Sweet almond) oil*, Cera alba (Beeswax)*, Butyrospermum parkii (shea) butter*, Cetearyl alcohol, Simmondsia chinensis (Jojoba) seed oil*, Rosa canina seed oil*

PRESERVATIVE: NONE

  • Sanctuary Hot Sugar Scrub (sold in Boots)

PEG-8 • Zeolite • Sucrose • Kaolin • Glycerin • Zinc Oxide • PEG-220 • Parfum (Fragrance) • Silica • Benzyl Salicylate • Linalool • Benzyl Benzoate • Hexyl Cinnamal • Limonene.

PRESERVATIVE: NONE (BUT THERE APPEARS TO BE HIGH LEVELS OF GLYCERIN AND ZINC)

  • Ole Henrickson Salt scrub

Glycerin, Sea Salt, Sodium Chloride, Butylene Glycol, Calcium Carbonate (CI77220), Caprylic/Capric Triglyceride, Glyceryl Stearate SE, Peg 100 Stearate, Ceteth-2.

PRESERVATIVES: NONE

(glycerine, glycols, salt are a hurdle but they are not official preservatives)

http://ec.europa.eu/health/scientific_committees/consumer_safety/docs/sccs_s_006.pdf

http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32013D0674#ntr11-L_2013315EN.01008301-E0011

http://oxfordbiosciences.com/safety/

http://www.staceyirvingconsultancy.co.uk/page_2785678.html

If being green in your manufacturing practice is of the utmost importance then you might want to try a cold process emulsifier. Cold process emulsifiers are normally liquid, water and oil soluble and can be used –obviously – without any heat.  This cuts processing time energy, both of which will have an impact on man power and the environment.   I don’t know about you but whenever I think I am going to spend some time in the lab with a liquid cold process emulsifier I always look forward to it. Normally they are really easy to use and are failsafe, providing of course, you follow the rules.  You do not have to weigh ingredients individually into separate containers and spend time heating.  When I am playing around formulating, I love to plan my formula, and then hit the tare on the scales.  Sometimes making a cream can take 5-10 minutes this way!

There are a fair few cold process emulsifiers on the market but many have their downfalls, some , particulary the natural ones, have no or virtually no consistency, then you have ones that are purported to be all in ones like Arisoflex AVC or Lecigel,  both being thickeners, emulsifiers and stabilisers – the downside is that they cannot tolerate electrolytes so are not suitable for some wonderful ingredients we know and love or preservatives that contain salts/sodium – something that needs to be considered if you want to go close to natural or claim to be paraben free.

I have wanted to try Heliogel for over a year and have used Lecigel on many occasion and also her more natural counterpart Ecogel but have been holding off on this one until today when I received my sample from Infinity Ingredients.

So what is Heliogel?

Heliogels INCI  is :  Sodium acrylates copolymer (and) Hydrogenated polyisobutene (and) Phospholipids (and) Polyglyceryl-10 stearate (and) Helianthus annuus (sunflower) seed oil

Appearance – its a Beige/brown cream as you can see from the picture.

heliogel-in-jar

 

Lucus Meyer describe it as

”… a polymer with the emulsifying properties of sunflower phospholipids to obtain a self-emulsifying system.  With its multifunctional profile, Heliogel™ is an essential formulating partner which can successfully be used in all kinds of face and body care with a 3-in-1 action:

  • It thickens formulas from 0.5% Heliogel™ has an increasing thickening power depending on the percentage of use.

  • It emulsifies all types of oil phases and makes the obtaining of O/W gel-creams easier, without additional emulsifier or HLB calculation. It requires neither pre-dispersion nor neutralization and can be hot or cold processed. It is preferable to add Heliogel™ into the oil phase although it can be mixed directly with the aqueous phase under strong stirring.

  • It stabilizes emulsions from 0.2%. Moreover, sunflower phospholipids, naturally rich in essential fatty acids, restore the cutaneous balance and reduce TEWL thanks to their film-forming properties. They offer emollient and protection to the epidermis keeping the skin moisturized.’’

The manufacturer states that it is  stable over a wide range of pH.   It gelifies from pH 2 to 12 with an optimal viscosity between pH 4 and 8. It is also compatible with ethanol and with electrolytes.

IS IT NATURAL?

Many of the ingredients would meet Ecocert standards however we have a problem when it comes to Sodium acrylates copolymer which is the sodium salt of Acrylic acid.  According to Wiki Acrylic acid is produced from propene which is a by product of ethylene and gasoline production.  As we know, gasoline is a mineral that is mined from the earth and then processed so to some it could be considered natural and to others (most people) not so much.  I would not consider this to be a sustainable product so if using sustainable ingredients or mineral derivatives is a no no for you then this product is probably is not for you.

Below are two formulas that I whipped up (in under 10 minutes I might add!)

Formula 1

heliogel-2

 

IMG_1646

Hydra Oxidant Post Shave Gel Cream with Pomegranate and HA

Stage INGREDIENT INCI
WATER WATER AQUA QS/UP TO 100
LARACARE 200 GALACTOARABINAN 1
HA Sodium hyaluronate 0.1
DERMOSOFT OMP Methylpropanediol, Caprylyl Glycol, Phenylpropanol 3
POTASSIUM SORBATE POTASSIUM SORBATE 0.3
OIL HELIOGEL Sodium acrylates copolymer (and) Hydrogenated polyisobutene (and) Phospholipids (and) Polyglyceryl-10 stearate (and) Helianthus annuus (sunflower) seed oil 3
POMEGRANATE CO2 EXTRACT Punica Granatum (Pomegranate) Seed Extract, and Rosmarinus Officinalis (Rosemary) Leaf Extract, 5
ROSEHIP FRUIT  CO2 EXTRACT Rosa Canina (Rosehip) Fruit Extract, Rosmarinus Officinalis (Rosemary) Leaf Extract, 5
Essential oil blend Lavender, parsley seed, amarys, orange 0.3

pH:  5.7

METHOD:  COMBINE EACH PHASE IN ORDER AND THEN ADD WATER TO OIL AND STIR RAPIDLY

Notes: I added the water to the oil phase as it was just easier to get it out of the pot, I suppose if you like being frustrated and you want a fight between the spoon and container you could do it the other way round.  This thickened upon stirring almost instantly. I was not impressed with the smell – it is hard to describe politely but it is a sweet animistic type of smell.  I managed to mask it with some essential oils.  In hindsight I think this might have been due to the combination of the Heliogel and the natural smell of the Pomegranate seed extract.

Formula 2

heliogel-1

Formula 2 on the right

Derma-cell Reboot with L-Arginine (FRAGRANCE FREE)

STAGE INGREDIENT INCI % USED
WATER GLYCERIN GLYCERIN 5
ARGININE ARGININE 0.1
WATER AQUA QS
OIL HELIOGEL Sodium acrylates copolymer (and) Hydrogenated polyisobutene (and) Phospholipids (and) Polyglyceryl-10 stearate (and) Helianthus annuus (sunflower) seed oil
PLANTASENS OLIVE OLIVE SQUALANE 10
GEOGUARD ECT Benzyl Alcohol, Salicylic Acid, Glycerin, Sorbic Acid 1

pH: 4.9

METHOD: SAME AS ABOVE

NOTE: This did not have the smell as I expect the preservative masked it. It smelt like the benzyl alcohol – marzipan/almond like so not unpleasant at all.

I was a bit worried when I combined the two phases as there was no thickening for about 20 seconds of rapid stirring and then over about a few minutes it thickened up. It then carried on thickening whilst resting so that it was, I would say pretty densely packed.

OVERALL HOW WAS IT?

Ease of use – so easy you don’t feel like you are formulating!

How did it feel – It is light and easily absorbed, a joy to use and rather elegant.  It has a slight stickiness to it which dissipated over a few seconds.  All in all, it is something that should be kept in any self respecting formulators tool kit for ease of use, functionality and its compatibility with a number of essential ingredients.

This is my final post about the Lucas Meyer emulsifying gelling agents.  We have looked at Heliogel and Ecogel – both with their own quirks and advantages and now on to what I would say is my favourite of the three in terms of skin feel and ease of use.  It is not completely natural which is a disadvantage for some and I certainly would not be able to use it in my own products however for anyone wanting to formulate a non natural product and wants an elegant, high end gel cream, then this is probably the one to use.  Some pretty massive brands are already using it and it won a prestigious award last year, so it is not to be scoffed at!  So what exactly is it?

This is what the manufacturer has to say:

LECIGEL™ is a gelling agent with emulsifying properties. It allows the increase in the viscosity and the stability of formulas. Suitable for both cold and hot processes, it also helps to adjust the viscosity at the end of the formulation process. Easy-to-use, it is compatible with most emulsifiers and is stable over a wide range of pH. Especially adapted for the formulation of gel-creams, it provides the typical “phospholipid touch” with a cool, soft and non-greasy skin feel.’

Lecigel’s inci is  Sodium acrylates Copolymer (and) Lecithin

Lucas Meyer recommends the following dosage.

  • As stabiliser: 0.2% and above
  • As thickener: 0.5% and above
  • As emulsifier: 0.5% and above for Lecigel™

Lecigel comes in the form of a beige powder that can be added at virtually any stage of formulation. This means that you can either put it in with the liquid oil phase and then disperse in with the water which will make it almost instantly thicken or you can add it to the water and then introduce it to the oil.  Putting it in a small amount of liquid that is not water, helps a little with dispersion but it is not necessary to do so.  It can also dusted in at the end of the process if you want. It is not sheer sensitive which means blending at high speeds will not break the gel.  You can use it hot so that comes in handy if you want to use hard butters that need melting. If you are using ingredients that need melting / heating I suggest that you heat the oil and water phase (lecigel can be in either) and then when the fat is melted and both phases are at a similar temperature, combine them.  I suggest doing this as you don’t want the cold water causing your fats to solidify before they have a chance to blend with the water/emulsifier.

Meyer suggests that you need at least an RPM of 1500 for full emulsification.  I have even hand stirred it.

Lecigel can emulsify up to 20% oil phase, 10% oils can be emulsified per each 1% of Lecigel and the final viscosity depends on the type of oils and butters used. Surprisingly, 1.5% Lecigel can take 20% ethanol (alcohol) too so if you wanted to use that as your preservative it is possible. It can tolerate up to 50% ethanol with 2% Lecigel.   It is also fairly resistant against electrolytes but the manufacturer advises to add them after emulsification if possible.  They also suggest that Lecigel has a synergy with xanthan and sclerotium gum which helps if you want to use electrolytes. So far so good! So what is it really like? I played around with this quite a bit. I have had it for quite some time (possibly over a year) and have been impressed each time I used it however I haven’t properly documented my experiments until now. I made a few creams with it, varying the  ingredients.  I also made two simple gels.

Firstly lets look at how it gelled. I made two gels, with no added oils.  One with 1%  Lecigel (Left) and the other with 0.5% Lecigel (Right).

img_3653

 

 

As You can see the one on the left is a lot thicker however it still feels very light with a very slight film when applied.  The one on the right is interesting, it is less viscous as one would expect with a more dewy like texture.  What is interesting is that it breaks down on the skin instantly releasing water with no residue.

 

 

 

 

The simple one

90 – Water/Aqua

8- Oryza Sativa (Rice) Bran Oil

1 – Lecigel

1 – Symtriol (preservative)

img_3651 img_3658

 

 

So this one has a very velvety skin feel, a nice rub-in and no greasy or sticky after-feel and and as you see has a lovely glossy look to it.

Lightening Multifunctional Night Cream for acne prone skin

lecigel-brightening-gel-cream

 

So this one was made for people who want something that will work some magic in the  night.  It contains niacinamide and glucosamine – this combination has been shown to help even out skin tone as well as  have a positive effect on fine lines and wrinkles. Bear berry extract has arbutin, a chemical thought to inhibit tyrosinase, the enzyme that controls melanin formation.  As we know melanin is the pigment responsible for tanning.  We also have pomegranate seed extract, a strong anti-oxidant which contains ellagic acid proven to reduce UV-induced cell death and counteracts inflammation. This combines well with Embilica extract, another strong antioxidant that protects against UV damage.

So, with all these extracts and actives how did Lecigel hold up?

As you can see below, it isn’t the prettiest of colours however it is lovely and glossy, applies smoothly and spreads really nicely with no oily, tacky residue but it does feel like there is a nice occlusive film on the skin. When squeezed out of an airless pump it doesn’t look so dark.  The colour comes from the Bearberry.

Lightening Night Treatment Cream

Vitamin C Day Balm

Finally, here is the last cream I made. It’s a whopping 10% tetra c gel cream. Its adjusted to pH 5.5 ish which did not seem to have a negative effect on the viscosity. I love lots of glycerin so I put 10% in and it is essentially oil free. So this is sticky and non greasy but it is for me and this level of glycerin is definitely not for everyone!

 

img_3649

vitamin-c-serum

 

So what the final word.  This is not for people that want to get their products certified by any organic standard however it is still a great product with so much potential.  It can be used at a fairly wide pH range and is tolerant to a small amount of electrolytes which can be helped with the use of xanthan and or sclerotium gum.  The texture is phenomenal whether you use 0.5 or 2%.  In the UK the distributor is Infinity Ingredients and it is also sold in small quantities from The Formulary.