When there is the presence of water in a cosmetic product, this makes it much more sensitive: preservatives are therefore mandatory. They are supposed to protect the product from external agents such as bacteria or simply light, but also to protect the consumer from possible contamination. Despite the raging controversies, not all conservatives are worth throwing away. Between antimicrobial preservatives and anti-oxidant preservatives, natural or synthetic, it is sometimes difficult to get by and especially to identify them! When we know that some are capable of crossing the skin barrier to end up in our body, it is better to know what we are dealing with.
This article was updated on 04/08/2023Why add preservatives to cosmetic products?
The purpose of preservatives in cosmetic products is toensure the preservation of the product over time. Well, we doubt you guessed it! There are actually 2 main types of preservatives: antibacterials/antifungals, and antioxidants. The preservatives will thus ensure the stability of the product over time, and above all its safety for its user. A poorly stored cosmetic product risks being degraded, both in terms of its smell, its appearance or its properties. It also risks creating allergic reactions or irritation. In short, nothing very happy. Basically we choose a cosmetic to improve something, it would be a shame to make it worse.
Antibacterial/antifungal preservatives will limit the development of unwanted little creatures: micro-organisms. For bacteria and fungi, cosmetic products are a bit like the Garden of Eden, life is good there! Nutrients and water are all they need for their development, and that's good, that's precisely what cosmetics provide them. Why not enjoy it ? Without the preservatives, your product would quickly have a superb hairy green, yellow or red layer on the surface. It's pretty but it's not entirely harmless.
The antioxidants will protect the cosmetic product from external physical agents which could modify its organoleptic qualities. Color, smell and appearance are all criteria that make us choose one product over another, so we would like it to last!
1st category: antimicrobial and antifungal preservatives
Why add it?
The risk of contamination of a cosmetic product exists throughout his life. At the very beginning of the chain, raw materials can be directly singled out if their conservation conditions have not been optimal. At the time of manufacturing, several factors may be involved. For example, we have staff who do not wash their hands after peeing (yes yes, it exists), the water which is used in the composition of the product and which may not be very clean, or during packaging where the product is in direct contact with the environment. When he finally ends up going through all these ordeals without any problems and he thinks he can end his life peacefully, the user buys it and comes and sticks his big paws in it. Brief, a cosmetic product is never peaceful. During all these stages, the microorganisms are just waiting for one thing: for the product to make a nice little place for them next to it. Nay! The presence of conservatives creates a blockade.
Microorganisms are found all over our body, including the skin. They have the lovely name of skin flora, and their purpose in life is to create a protective barrier for us. Without this, various infections would readily appear! Preservatives may be antibacterial and antifungal, but they must nevertheless respect this bacterial flora at the risk of bringing more harm than good. The selection of a preservative for a given cosmetic product is done according to different criteria such as its pH, its solubility in water, its spectrum of activity, and of course its safety, in connection with legislation. Not every conservative is equal, this is why there is such a diversity, and why it is so difficult to find your way through the list of ingredients!
Preservatives authorized in organic cosmetics
Even organic cosmetic products are required to contain preservatives. Although these can sometimes be slightly irritating or drying, they always present fewer risks than those present in conventional preservatives. Here are the ones we find most frequently:
- benzoic acid (INCI: benzoic acid)
- sorbic acid (INCI: sorbic acid)
- benzyl alcohol, or Cosgard (INCI: benzyl alcohol)
- dehydroacetic acid, DHA or Geogard (INCI: dehydroacetic acid)
- potassium sorbate (INCI: potassium sorbate)
Preservatives of natural origin
Finally, there are completely natural preservatives. Some can be found in commercial cosmetic products, but for the most part they are mainly used for making homemade cosmetics:
- natural alcohol, or Alcohol, from the fermentation of fruits or cereals,
- EPP, grapefruit seed extract or Citrus grandis seed extract
- Leucidal or Leuconostoc/Radish Root ferment: obtained by fermentation of radish with Leuconostoc kimchii,
- Naticide or Plantaserve Q
And what about essential oils in all this?
You may sometimes read that essential oils are natural preservatives. Yes and no. Essential oils do indeed contain anti-bacterial, antifungal and antiviral properties, but are not necessarily suitable for making cosmetic products. Essential oils can therefore improve the conservation of your cosmetic products compared to a product that does not contain them, but they are not strictly speaking considered preservatives. So don't expect to keep your cream for 3 months just because you added 3 drops of Tea Tree!
Antimicrobial and antifungal preservatives to avoid
Some preservatives can cause serious harm to health, which is why they are controversial. If for some this has been proven, for others it is only suspected. In any case, prevention is better than cure and avoiding them! It's time to start the shock documentary music: here are some of the best known.
The famous parabens
Because yes, there are several depending on the length of the alkyl chain R. We thus find methylparaben, ethylparaben, propylparaben, isopropylparaben, butylparaben, isobutylparaben and benzylparaben. Just that ! According to the numerous research carried out, these compounds are not degraded by the enzymes of the human body, which would imply chronic long-term toxicity. Several studies have been carried out on it, and several hypotheses have been put forward. One of them would be that parabens are estrogen-like, which would explain their involvement in the appearance of breast cancer. Another explains that parabens have effects on reproduction. What is certain is that long-chain parabens are those that present the most risks. This is particularly the case for isopropylparaben, isobutylparaben, phenylparaben, benzylparaben and pentylparaben which have been banned since 2014. Currently, butylparaben and propylparaben are still authorized but highly regulated. All that remains is methylparaben and ethylparaben which are “considered safe” by the authorities. So something to follow for parabens… With all this history, the word “paraben-free” has become a real commercial argument. Before claiming glory, you should still know that if manufacturers do not use parabens in their product, they are entitled to use any other preservative, and some are unfortunately more criticized than parabens. So be wary of the words “paraben-free”!
Triclosan
Triclosan is an antibacterial compound used on the one hand for this very property, in toothpastes and deodorants for example, and on the other hand as a preservative. It is also highly regulated, and is only authorized in certain categories of cosmetic products. On the one hand, studies aim to demonstrate that it creates resistance to certain germs, and therefore reduces the effectiveness of antibiotics. On the other hand, it is suspected of being an endocrine disruptor, of acting on the thyroid, reproduction and development. Finally, it would increase the allergic risk. Although it is increasingly regulated, this does not prevent it from being a component that can be found everywhere, even in unsuspected places like kitchen utensils or toys! So even if your cosmetic contains very little, there is a big risk of overdose.
Formaldehyde and formaldehyde releasers
Formaldehyde is a preservative which is now clearly identified as being carcinogenic by the respiratory route. For this reason, it is no longer found in aerosols... Unlike other cosmetics. Although it is regulated in Europe, it can still be found at a maximum of 0.2% in the composition of cosmetics, and up to 5% in nail hardeners. If they are criticized, it is in particular because they are very irritating and allergenic. Have you read and reread the INCI list for your cosmetic product and have not seen the slightest trace of formaldehyde? Phew! Although... To escape this, we are now resorting to other compounds which, ironically, can release formaldehyde under certain conditions (pH, temperature, etc.). And no big surprise, they too are unfortunately responsible for irritation and allergic reactions. To cite just a few examples, we have DMDM hydantoin, diazolidinyl urea, imidazolidinyl urea, 2-bromo-2-nitropropane-1,3-diol, benzylhemiformal, sodium hydroxymethylglycinate, Quaternium-15 , or polyquaterniums.
Cetrimonium bromide
Cetrimonium bromide is also singled out for its irritant and allergenic risk on the skin. Of synthetic origin of course, this ingredient is composed of quaternary ammonium. It is generally used in cleansing products such as micellar waters, and is limited to 0.1%, which is not insignificant.
Thiazolinones
By thiazolinone, we mean 2 major compounds in particular: methylchloroisothiazolinone and methylisothiazolinone. HAS your wishes. When the risks of parabens were revealed, many manufacturers turned to thiazolinones. As they have been used, thiazolinones have unfortunately been designated as highly allergenic. They were even voted “allergen of the year 2013” in the United States. The blend of these two preservatives is known as Kathon CG, and has already made a name for itself.
Phenoxyethanol
Currently, phenoxyethanol is a preservative that can be found in many cosmetic products. However, it is limited to 1% and for good reason: it presents numerous risks to human health. It is part of the glycol ether family, which includes around 80 derivatives, some of which are very toxic. Although no study has really been carried out on the chronic or acute toxicity of phenoxyethanol on humans, many doubts remain. First of all, it would have a proven allergenic and irritant risk, particularly to the eye, and would be responsible for neurological disorders. The biggest risk of this preservative is at the level of reproduction: sterility, abnormalities in menstrual cycles, spontaneous abortions and malformations are the main effects noted. In short, nothing very reassuring! For all these reasons, the ANSM prohibits the use of phenoxyethanol in cosmetic products intended for babies, and limits it much more than normal in products intended for children under 3 years old: 0.4%. If all this doesn't really make you want to come across cosmetic products that contain it, here is its little INCI name, the one under which it appears in the list of ingredients: phenoxyethanol, 2-phenoxyethanol or phenoxytol.
2nd category: Antioxidant preservatives
Why do cosmetic products oxidize?
Antioxidants in cosmetic products are used for 2 main reasons: on the one hand they aim to protect the cosmetic product from oxidation, and this is what will interest us, and on the other hand protect the skin from free radicals, and that's another subject. Before getting started, it is important to remember what oxidation is. A little flashback to your high school years: an oxidation is a reaction during which a reactant loses one or more electrons. In everyday language, we often speak of oxidation when oxygen is the culprit. And where is oxygen found in high proportions? In the air, bingo! In our cosmetic products, it is not the water that is targeted this time, but the oily phase of the product, and more particularly the fatty acids which make up vegetable oils. The oxygen will react with the double bonds of the fatty acids, those called unsaturated fatty acids. The quantity of unsaturated fatty acids varies enormously from one vegetable oil to another, which is why Rosehip oil will be much more sensitive to oxidation than Jojoba oil for example! The more unsaturated fatty acids a vegetable oil contains, the more double bonds there will be, and the more oxygen molecules will have a field day. To add a layer, other factors come into play in the oxidation of the product, exogenous factors this time. By misnomer, we often speak of oxidation by UV rays of light, etc. Nay! In reality, light is only an accelerator of oxidation phenomena. This is not the only one unfortunately, contact with metals (Iron or Copper), and heat are also part of it. This is why it is imperative to keep your cosmetic products away from any source of light and heat. When they are oxidized, fatty acids produce new compounds whose effects we cannot control, these are the famous free radicals. The oil is then called rancid, it can change color, odor, texture, and its properties are altered. In short, it is good to throw away. In cosmetic products, it's all the same. If the oil that composes it is oxidized, this results in a change in its organoleptic characteristics. If you have any doubt: trash!
Antioxidant preservatives to avoid
There are 2 major antioxidant preservatives to avoid, these are BHT (butylated hydroxytoluene) and BHA (butylated hydroxyanisole). Very few studies have been carried out on BHT, but this does not prevent many doubts about its safety. At high doses, it could be an endocrine disruptor, have effects on reproduction and promote the development of tumors. BHA is found less and less in cosmetic products, unlike BHT, and for good reason: it is carcinogenic according to the IARC, the International Agency for Research on Cancer. Finally, both would be responsible for allergies and have a sensitizing potential.
Antioxidant preservatives used in organic and natural cosmetics
Certain ingredients such as vegetable oils naturally contain antioxidant agents. However, this is often not powerful enough and it is necessary to add more to ensure better product protection. The two main antioxidants used are therefore vitamin E found under the INCI name Tocopherol or Tocopheryl acetate, and the CO2 extract of Rosemary, Rosmarinus officinalis leaf extract.
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