Preservatives in cosmetics are a sensitive topic, and so we want to explain to you that preserving is not bad — in fact, it is indispensable.
Preservatives are substances that prevent the multiplication of bacteria (gram+ and gram-), yeasts, fungi and moulds by disrupting the cells and spores where they germinate, and thus make their growth impossible, thereby extending the shelf life of your product, on average by 2 to 3 months.
They are an indispensable part of products that contain water — not only pure water, but also water-based raw materials such as hydrosols or aloe vera gel. It must be kept in mind, however, that most purely natural products are more prone to the formation of microorganisms.
Fact or myth: what threatens your product
It really is very likely that your product can be contaminated even if you work under hygienic conditions and everything is clean.
Here are several of the most essential factors that literally make your natural product a paradise for the formation of microorganisms:
- high water content
- humidity of the environment in which the product is stored or used – a humid and warm bathroom environment becomes ideal for the growth of bacteria
- content of hydrosols, plant extracts or dried plants in the product
- content of clays or natural gums in the product
- temperature of storage and the temperature at which the product is applied
- pH value of approximately 4.5 to 6.5 (in fact, bacteria can thrive in the range of pH 4 to 9, yeasts and moulds from 3 to 9)
Is it necessary to preserve anhydrous products?
It is not necessary to preserve all products. For example, soap made by the cold process, where a sodium hydroxide solution was used, does not require a preservative.
However, if you have a product without water into which water from the surroundings gets, it is recommended to preserve such a product.
Attention: do not be misled by the oil base of your product. If you were to use an oil-soluble preservative, the preservative would remain in the oils; it would not move and act exactly where the water is located, which means its use would become pointless.
It is therefore necessary to use a water-based preservative and to ensure that it is mixed with the oil phase by adding an emulsifier.
Think about your health
The very fact that you have chosen to make your own natural cosmetics shows that your health is your priority. Therefore, do not underestimate the possibility of the occurrence of bacteria, which, in the case of reduced immunity or damaged skin, can cause unpleasant health problems. Although we cannot see them with the naked eye, they are present in your product in an appropriate amount and are not visible with the naked eye even in the initial stage of their overgrowth.
Important: we would also like to point out the excessive application of preservatives into your products. It is not true here that the more you use, the longer your product will last.
Preservatives are used to a minimal extent, from 0.5 to 4%. Remember that just as they destroy bacteria, in a high proportion they can also destroy your skin. Always follow the recommended dosage, therefore.
How to choose the right preservative
Learn to read product information correctly
Today you will find a large number of preservatives on the market. You can choose a natural or a synthetic one. Sometimes even the name of the preservative itself is quite confusing — it is often the trade name of the product or just an abbreviation. It is therefore important to know how to read product information: the INCI, which should contain all the components of the product, and those you can then check for yourself.
It is also useful to know whether the product is approved for use in natural cosmetics by certification bodies such as COSMOS, Ecocert, Natrue or Soil Association.
Suitability of a preservative based on the nature of your product
The nature of your product plays an important role, so it is necessary that you have defined what kind of product it is. Here are some basic questions:
- Is it a water-based product, such as a toner?
- Is it a W/O or O/W emulsion? (more about the differences between W/O and O/W emulsions in our article O/W or W/O?)
- Is it a product that is rinsed off after application or left on the skin?
- Is the product applied to the hair, the skin around the eyes, the face, the whole body, or is it baby cosmetics?
pH value of the product
Another important point is pH. It is very important to realise that most natural preservatives are weak acids (such as salicylic acid, benzoic acid, sorbic acid, etc.). All of them are only slightly soluble in water as acids, which is why most of them are supplied as a sodium or potassium salt, for example sodium benzoate. But they are effective only in the acid form. This means that in order to introduce them into the product you will need the sodium or potassium salt, but in order for them to be effective the acid form will be necessary.
So why measure the pH of your product carefully? Because pH significantly affects the effectiveness and solubility of the preservative. If the pH is low, the preservative will start to sediment in the product and can cause destabilisation of the product. If, on the other hand, the pH is high, the preservative loses its effectiveness.
Therefore, check at which pH the given preservative is effective. We remind you that bacteria can thrive in the range of pH 4 to 9, yeasts and moulds from 3 to 9, which includes the pH of the skin of 4.0 – 6.5.
Preservative substances in the ingredients of your product
This is a very important matter! Before you choose a preservative, you have to take into account the fact that some ingredients in your formulation may already contain a preservative component (hydrosols, for example, are often preserved with sodium benzoate).
First of all, it is therefore necessary to choose a preservative that is compatible with the preservatives in the raw materials and at the same time to calculate how much preservative preparation you can still use so that you do not exceed the correct level and “overdose” your final product. The application dosages of individual preservatives range from 0.8% to 4.0%.
Spectrum of a preservative’s effect
When choosing the right preservative, it is just as important to check which contaminating substances the preservative is effective against. Gram-positive and gram-negative bacteria, yeasts and moulds occur most frequently in cosmetic products.
Therefore, if you have a preservative at home that does not cover this whole range of contaminants, its effectiveness needs to be supplemented with an additional preservative.
Influence of the preservative on the character of the final product
Can a preservative affect the scent, colour or viscosity of a product? Yes, this can happen, especially with natural preservatives, which are extracts from nature and therefore mostly have their own scent and colour. However, do not be discouraged: their use is at most up to 4%, and unless you want your product to be completely without scent and odour, you will not notice the preservative in it.
In the case of emulsions, it is necessary to monitor any undesirable changes in viscosity. However, it is again only about practical testing and finding the most suitable one for your product.
Tip: it is also important to check whether the given preservative is sensitive, for example, to light, as a result of which it oxidises. Therefore, consider this aspect as well and choose the right packaging for your preserved product.
Overview of preservatives
In our offer you will find both natural preservatives and preservatives of synthetic origin. In this case it is not so important which origin of raw material you choose, but rather that you use a preservative that is effective across the range of action of the microorganisms whose multiplication you need to prevent.
Since more and more producers of natural cosmetics who do not produce only for their own needs are beginning to appear in our circles, the list below is dedicated precisely to them.
If you are a manufacturer of cosmetics, you certainly already have this information determined and you know exactly which preservative is best for your products. In this case we also recommend having a microbiological test carried out in a laboratory, because this is the only guaranteed way to check whether the chosen preservative is effective.
However, if you produce at home for your own purposes, you do not need to worry so much about determining this. In your home conditions one piece of advice will suffice: simply choose the preservative with the widest spectrum of effectiveness — that is, one that also covers the type of bacteria whose multiplication you need to prevent — and use the correct ratio of preservative in your product. If you produce reasonable quantities that you can use up within a few months, the preservative will effectively protect your product during that period from the overgrowth of undesirable microorganisms.
How to read the profiles: below are the properties of the individual preservatives — solubility, effective pH, dosage and colour. Current availability and pack sizes can be found in the Preservatives category.
Grapefruit seed extract
This is a natural product that acts as a natural antibacterial, antiparasitic, antifungal and antiviral inhibitor in soaps, facial toners and other cosmetic products. It is soluble in water, alcohol and organic solvents.
Use and application: as far as water-based products in particular are concerned, we recommend supplementing it with other preservatives so that effectiveness against microorganisms is covered.
Cosgard
Cosgard is a natural preservative that meets the standards of Ecocert and COSMOS, NaTrue Certified and Soil Association – dehydroacetic acid and benzyl alcohol are organic compounds that are accepted for use in natural cosmetics.
Effectiveness: broad-spectrum, highly effective against gram+ bacteria, partly against gram- bacteria and fungi. It is most effective below pH 5.5.
Its use is really wide. You can use it in the following products: shampoos, conditioners, facial and liquid soaps, shower gels, facial toners for sensitive skin, baby wipes and cloths, moisturisers, creams, baby shampoos, hair preparations, bubble baths, sunscreens.
It is almost odourless, so it lets the added fragrances of the product stand out. The colour has a slightly yellowish tinge, which is faintly visible in clear toilet waters; in other cosmetics it does not influence the colour of the final product.
Dermosoft 1388
Dermosoft 1388 is a mixture of organic acids derived from plants with broad antimicrobial activity, certified by Ecocert. It is therefore a natural preservative.
Effectiveness: against bacteria (both gram+ and gram-) and fungi.
Use: water-based products, from gels to emulsions (if the product is oil-based, it is necessary to use a solubiliser).
Tip: you can increase its activity by using 0.1% of the natural chelating agent PA-3. If you want to increase its effectiveness against yeasts, we recommend combining it with GMCY.
Dermosoft GMCY
GMCY is a purely natural product – it is an ester of glycerin with caprylic acid, certified by Ecocert. In addition to being a preservative, it is also used as an emulsifier and emollient.
Effectiveness: against bacteria (both gram+ and gram-). In the case of the water phase, it is incorporated using a solubiliser.
It is solid and melts at just 30 – 35 °C.
Tip: it combines very well with Dermosoft 1388 to achieve a broader spectrum of effectiveness.
Naticide
Naticide is a natural preservative. Interestingly, it is actually a fragrance (a mixture of vanilla and almonds), so once it has been used you can state that your product is preservative-free, because it is not classified as a traditional preservative.
Effectiveness: effective against gram+ and gram- bacteria, yeasts and moulds.
In water it is soluble only up to 0.6%, so the remaining 0.4% must be added in the cooling phase.
Use: facial toners (oil-based and dry), face creams and masks, shampoos, antiperspirants, body milks and gels.
Versatil TBG
This is a preservative approved by Ecocert, COSMOS and Natrue. It is not soluble in water, therefore a solubiliser is needed to incorporate it into the formulation. It works on a water base.
Effectiveness: effective against gram+ and gram- bacteria and yeasts (for emulsions and water-based products it is sufficient; for shampoos, soaps and surfactant-based products its effects need to be supplemented with another preservative).
Use: toners, gels, emulsions, deodorants, hair conditioners.
Tip: for better effectiveness you can combine Versatil TBG with Dermosoft 1388.
Euxyl PE 9010
Euxyl is a synthetic broad-spectrum preservative, effective against gram+ and gram- bacteria, yeasts and moulds. It does not contain parabens or formaldehyde.
It has limited solubility in water (1% at 20 °C), but is easily soluble in polar solvents such as propylene glycol and 1,3-propanediol. It is slightly soluble in glycerol and sorbitol.
Use: creams, facial lotions and serums, wet wipes, shampoos, conditioners, body care cosmetics.
We believe that our posts have provided you with a sufficient information base, and we keep our fingers crossed for you when testing our preservatives.
The current range of natural and synthetic preservatives, including pack sizes and availability, can be found in the e-shop.
