When there is the presence of water in a cosmetic product, it 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 protect the consumer from possible contamination. Despite the controversies that rage, not all preservatives are good to throw away. Between antimicrobial preservatives and antioxidant preservatives, natural or synthetic, it is sometimes difficult to identify them! When we know that some are able to cross the skin barrier to end up in our body, it is better to know what we are dealing with.
The purpose of preservatives in cosmetic products is to ensure the preservation of the product over time. Well, we suspect you guessed it! There are actually 2 main types of preservatives: antibacterial/antifungal, and antioxidants. The preservatives will thus ensure the stability of the product over time, and especially its safety with respect to its user. A poorly preserved cosmetic product risks being degraded, both in terms of its smell, its appearance or its properties. It may also create allergic reactions or irritation. In short, nothing to be happy about. 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 undesirable little bugs: microorganisms. For bacteria and fungi, cosmetic products are a bit of a Garden of Eden, it's a great place to live! Nutrients and water are all they need for their development, and that's just what cosmetics provide. Why not take advantage of this? Without preservatives, your product would quickly show a beautiful green, yellow or red hairy layer on the surface. It's pretty, but it's not entirely harmless.
As for the antioxidants, they will protect the cosmetic product from external physical agents that could modify its organoleptic qualities. Color, smell and appearance are all criteria that make us choose one product over another, so we'd just as soon make it last!
The risk of contamination of a cosmetic product exists all along its life. At the very beginning of the chain, raw materials can be directly blamed if their preservation conditions have not been optimal. At the manufacturing stage, several factors can be at fault. We have for example the staff who do not wash their hands after having peed (yes, it exists), the water which enters the composition of the product and which can be not very clean, or during the conditioning where the product is in direct contact with the environment. When it finally gets through all these ordeals without any trouble and thinks it can finish its life in peace, the user buys it and comes to stick its big palms in it. In short, a cosmetic product is never serene. During all these steps, microorganisms are only waiting for one thing: for the product to make them a little warm place at its side. Que nenni! The presence of preservatives makes blockade.
Microorganisms are found all over our body, including our skin. They are called skin flora, and their purpose in life is to create a protective barrier. Without it, various infections would be a welcome sight! Preservatives may be antibacterial and antifungal, but they must still respect this bacterial flora or risk doing 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 the legislation. Not all preservatives are created equal, which is why there is such a diversity of them, and why it is so difficult to find your way through the list of ingredients!
Even ORGANIC, cosmetic products are obliged to contain preservatives. If these can sometimes be slightly irritating or drying, they always present less risks than those present in conventional preservatives. Here are those that are most frequently found:
Finally, there are totally natural preservatives. Some of them can be found in commercial cosmetics, but for the most part they are mainly used for home cosmetics:
You may read some times that essential oils are natural preservatives. Yes... and no. Essential oils do indeed contain anti-bacterial, anti-fungal and anti-viral properties, but they are not necessarily suitable for cosmetic products. Essential oils can therefore improve the preservation of your cosmetic products compared to a product that does not contain them, but they are not strictly speaking considered as preservatives. So don't expect to keep your cream for 3 months just because you added 3 drops of Tea Tree!
Some preservatives can cause serious damage to health, that's why they are controversial. If for some it has been proven, for others it is only suspected. In any case, it is better to prevent than to cure and avoid them! It's time to start the music of shocking documentaries: here are some of the most famous.
Because yes, there are several depending on the length of the alkyl chain R. We find methylparaben, ethylparaben, propylparaben, isopropylparaben, butylparaben, isobutylparaben and benzylparaben. That's it! According to the numerous researches carried out, these compounds would not be degraded by the enzymes of the human body, which would imply a long-term chronic toxicity. Several studies have been conducted on them, and several hypotheses have been put forward. One of them is that parabens are estrogen-like, which would explain their implication in the appearance of breast cancer. Another explains that parabens have effects on reproduction. What is certain is that the long-chain parabens are those that present the most risk. This is particularly true of isopropylparaben, isobutylparaben, phenylparaben, benzylparaben and pentylparaben, which have been banned since 2014. Currently, butylparaben and propylparaben are still allowed but highly regulated. Only methylparaben and ethylparaben remain, which are "considered safe" by the authorities. With all this history, the mention "without paraben" has become a real commercial argument. Before shouting glory, it is necessary to know that if the industrialists do not use parabens in their product, they are entitled to use any other preservative, and some are unfortunately more criticized than the parabens. So beware of the mention "without parabens"!
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 too is highly regulated, and is only authorized in certain categories of cosmetic products. On the one hand, studies aim to show that it creates resistance to certain germs, and thus reduces the effectiveness of antibiotics. On the other hand, it is suspected of being an endocrine disruptor, acting on the thyroid, reproduction and development. Finally, it would increase the allergic risk. If it is more and more regulated, it is 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 overdosing.
Formaldehyde is a preservative that is now clearly identified as a respiratory carcinogen. 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. You have read and reread the INCI list of your cosmetic product and have not seen the slightest trace of formaldehyde? Phew! To avoid it, we now use other compounds which, ironically, can release formaldehyde under certain conditions (pH, temperature,...). And no big surprise, they too are unfortunately responsible for irritations and allergic reactions. To mention only 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 is also pointed out for its irritating 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 water, and is limited to 0.1%, which is not insignificant.
Thiazolinone refers to 2 major compounds in particular: methylchloroisothiazolinone and methylisothiazolinone. Bless you. When the risks of parabens were revealed, many manufacturers turned to thiazolinones. As their use increased, thiazolinones were unfortunately designated as strong allergens in their own right. They were even voted "allergen of the year 2013" in the United States. The mixture of these two preservatives is known as Kathon CG, and has already made quite a name for itself.
At present, phenoxyethanol is a preservative that can be found in many cosmetic products. Nevertheless, it is limited to 1% and for good reason: it presents many risks on human health. It is a member of the glycol ether family, which includes about 80 derivatives, some of which are very toxic. If no study has really been done 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, in particular at the ocular level, and would be responsible for neurological disorders. The biggest risk of this preservative is at the level of reproduction: sterility, abnormal 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 the seat of babies, and limits it much more than normal in products intended for children under 3 years: 0.4%. If all this doesn't really make you want to come across cosmetic products that contain it, here's its little INCI name, the one under which it appears in the list of ingredients: phenoxyethanol, 2-phenoxyethanol or phenoxytol.
Antioxidants in cosmetic products are used for 2 main reasons: on the one hand, they aim to protect the cosmetic product from oxidation, and that's what we're going to be interested in, and on the other hand, to protect the skin from free radicals, and that's another topic. Before we get started, it's important to remember what oxidation is. A quick flashback to your high school days: an oxidation is a reaction in 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 water that is targeted this time, but the oily phase of the product, and more particularly the fatty acids that make up the vegetable oils. 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 an oil of Rose Hip will be much more sensitive to oxidation than an oil of Jojoba for example! The more unsaturated fatty acids a vegetable oil contains, the more double bonds it will have, and the more oxygen molecules will have a field day. To add another layer, other factors come into play in the oxidation of the product, exogenous factors this time. By abuse of language, we often speak of oxidation by UV rays of light etc. Nonsense! In reality, light is only a gas pedal of oxidation phenomena. Unfortunately, it is not the only one, contact with metals (iron or copper) and heat are also part of it. That is why it is imperative to keep your cosmetics away from any source of light and heat. When they are oxidized, fatty acids produce new compounds whose effects are not controlled, these are the famous free radicals. The oil is then described as rancid, it can change color, smell, texture, and its properties are altered. In short, it is good to throw away. In the cosmetic product, it is all the same. If the oil in it is oxidized, it results in a change in its organoleptic characteristics. If you have a doubt: trash!
There are 2 major antioxidant preservatives to avoid, BHT (butylated hydroxytoluene) and BHA (butylated hydroxyanisole). Very few studies have been conducted on BHT, but this does not prevent many doubts about its safety. In high doses, it could be an endocrine disruptor, have effects on reproduction and promote the development of tumors. As for BHA, it is less and less found in cosmetic products, unlike BHT, and for good reason: it would be carcinogenic according to the IARC, the International Agency for Research on Cancer. Finally, both would be responsible for allergies and would have a sensitizing potential.
Some ingredients such as vegetable oils naturally contain antioxidants. However, this is often not powerful enough and it is necessary to add some to ensure a better protection of the product. The two main antioxidants used are vitamin E found under the INCI name Tocopherol or Tocopheryl acetate, and Rosemary CO2 extract, Rosmarinus officinalis leaf extract.
To summarize, no preservative ensures perfect safety for the skin and the body. Due to their properties, none are harmless, but let's not forget that it's the dose that makes the poison. Since they can all cause damage, they remain highly monitored and studied by the authorities. To guard against any risks, several choices are therefore possible: take note of the list of ingredients in conventional products in order to avoid preservatives that are too controversial, opt for organic cosmetics whose preservatives are generally more trustworthy, or simply make your own cosmetics! This last choice allows you to make recipes perfectly adapted to your skin type, to know the exact composition of the mixture, but above all to limit or even avoid the use of preservatives that are too risky.