Cosmetic components: Preservatives

Preservatives in cosmetics are a frequent topic of discussion and speculation in the popular and scientific press. Preservatives must provide protection of the cream from a wide range of organisms (bacteria, fungi) for a long time. Cosmetics are used for several months (or even years), so the content of preservatives is the storage conditions for which cosmetics are designed. At the same time, most sterilization methods adopted in the food industry (lyophilization, sterilization of packaging, storage at low temperatures) are unsuitable for cosmetic production. Therefore, at least for microbial cells, the preservative must definitely be toxic.

A preservative can also be toxic to skin cells. Today, scientists are working on creating preservatives with the broadest possible spectrum of action, so that there is no need to introduce several preservatives into the formulation.

Preservatives are included in cosmetics whenever possible in the minimum concentration, at which they are effective against microbes and are not toxic to the skin. Let us note once again that in fact, absolutely any component of a cosmetic product can cause unwanted skin reactions. It is just that some substances have a higher toxic potential than others. Preservatives, along with surfactants, are traditionally considered one of the main causes of allergic reactions and dermatitis in people with sensitive skin. Of course, there is some truth in this. And yet, one cannot but agree that preservatives are less harmful than microbes and microbial toxins, as well as the products of decomposition of cosmetic ingredients by microbial flora. Therefore, preservatives should be in cosmetics, and they cannot be completely abandoned.

Some natural components also have the property of slowing down the spoilage of cosmetic products, such as plant extracts (birch leaves, pine bark and many other plants), sodium benzoate (found in cranberries, currants), essential oils, propolis, salts, seaweed extract, rich in iodine. The introduction of these substances into the recipe allows to reduce the concentration of synthetic preservatives (if this is the task).

Cosmetics "without preservatives" cannot be used for a long time, and it is better to store them in the refrigerator. Otherwise, there is an increase in microbial flora, as well as inactivation of active additives.

Antibacterial additives used are not traditional cosmetic preservatives, but completely different compounds. Among them are non-specific bactericidal agents (ethyl alcohol, acetone, iodine-containing compounds, plant extracts, essential oils, etc.) and specific substances that block a certain stage of microbial cell metabolism (antibiotics).

There are several groups of cosmetics with antibacterial properties: anti-acne products, anti-dandruff shampoos, antimicrobial soaps, deodorants-antiperspirants. In this series, anti-acne products stand apart. Firstly, they are usually not washed off and remain on the skin for a long time. Secondly, the skin to which they are applied has a damaged barrier and its own protective mechanisms are weakened, thirdly, dysbacteriosis, accompanied by inflammation, is often observed on skin with acne. Therefore, cosmetics for the care of problem skin acne have their own characteristics and are very close to medical drugs.

As for other groups of antibacterial cosmetics, legislators in different countries evaluate them differently. Thus, in the USA, the presence of antibacterial ingredients in cosmetics immediately transfers the drug from the category of cosmetic products to drugs. Deodorants in the USA immediately become "drugs" as soon as it is stated that the deodorizing effect is based on the antimicrobial effect. Therefore, antiperspirants in the USA are included in the category of drugs. The group of products represented by antibacterial soaps has become a real bone of contention between the cosmetic industry and the FDA. The FDA ruled that soaps presented on the market as antibacterial are classified as drugs. Frankly speaking, any soap has antibacterial properties, because the dominant components of soap are surfactants. Surfactants in soap are not dangerous for the skin, but the bacteria on its surface die.

The most well-known antibacterial component for soap is triclosan. The media periodically reports that triclosan is toxic to the skin. This is nothing more than another speculation, since to date none of the numerous large-scale studies have confirmed this. But the question of the advisability of including triclosan in soap is quite natural, especially since there are additional reasons for this. In order to really effectively affect the microbial flora living on the surface of our skin, it is necessary to introduce an antimicrobial agent in a higher concentration. Thus, we increase the risk of adverse reactions (irritation, allergies), on the one hand, and completely without any reason seriously disrupt the microbiological balance, on the other.

And so the preservative must:

• A preservative or preservative system must be safe when the cosmetic product containing it is used for its intended purpose.
• A preservative or combination of preservatives must be compatible with all ingredients of the system and must not lose activity due to interaction with other components. The introduction of preservatives must not affect the consumer properties of cosmetic products.
• The ideal preservative should not introduce odor or color into the cosmetic product or react with the ingredients of the system to cause a change in color or odor.
• The preservative must be stable at all temperatures and pH values encountered in cosmetic production.
• An ideal preservative should work both during the manufacturing process and throughout the entire planned shelf life of the cosmetics.

It should be emphasized that the most important thing for a cosmetics manufacturer is to choose a preservative that is truly effective against microbes and safe. Price is a secondary factor. Much more serious are possible complaints from customers or the media, which can seriously damage the reputation of a cosmetics company. This will cost the company immeasurably more than saving on a cheap preservative that will not work.

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