An article by Sara Brace

Preservatives keeping your cosmetics clear.

It is commonly known that cosmetics must be preserved from deterioration, although do we really know what that means? This article will talk about preservatives, what they are, their role in cosmetics as well as their possible side effects.

Let’s start by explaining what a preservative is. A preservative, whether natural or synthetic, is an added ingredient in products to shield them from decay. Just like other pharmaceutical items, manufacturers must shield cosmetics from microbial contamination to ensure their safety and extend their storage life. (1-2)

Why preserving cosmetics?

Our skin and the ambient air constantly host bacteria, yeasts, and molds, which can inadvertently infiltrate products during normal usage. Ingredients like water, oils, peptides (meaning “a compound consisting of two or more amino acids linked in a chain”), and carbohydrates (which are “any of a large group of organic compounds that includes sugars, starch, and cellulose, containing hydrogen and oxygen in the same ratio as water (2:1) and used as structural materials and for energy storage within living tissues”) found in cosmetics provide an ideal breeding ground for germs. (2) That’s the reason why the absence of preservatives could lead to product spoilage, diminishing their effectiveness and potentially causing skin or eye infections. Manufacturers mitigate the effects of contamination in our cosmetics by employing two separate categories of substances: antimicrobial preservatives, which target microorganisms, and antioxidant preservatives, which suppress oxidation processes triggered by exposure to air and the creation of free radicals.

This is an image posted on Cosmetics Europe.

Here we can appreciate the effect of prevention that preservatives have on our cosmetics. The left image shows a cream with preservatives. You can see that after two weeks, the cream with preservatives remains in optimal condition, while the cream without preservatives is completely spoiled.

The effect of preservatives on cosmetics: with and without at day 0 and 14.

Preservation methods

To mitigate the effects of contamination in our cosmetics, manufacturers employ two separate categories of substances: antimicrobial preservatives, which target microorganisms, and antioxidant preservatives that suppress oxidation processes triggered by exposure to air and the creation of free radicals. (3) Commonly employed preservatives in the cosmetic industry include substances like parabens, formaldehyde releasers, and triclosan. (2) The antimicrobial action of these chemical agents varies according to their chemical composition. Apart from utilizing antimicrobial agents for preservation, the cosmetic industry employs additional tactics such as managing water activity, incorporating multifunctional ingredients as well as acting on pH levels. The ideal pH range for the growth of microorganisms in cosmetic products is 5 to 8. Any pH level outside this range creates unfavorable conditions, leading to a reduction in their growth rate. For instance, cationic hair conditioners have an acidic pH, 4 approximately, while soaps have an alkaline pH between 9.5 and 10.5. (3)

Pros and cons of preservatives in cosmetics

So far, we have discussed the advantages of using preservatives in cosmetic products. However, it is essential to address the potential disadvantages associated with this strategy. After cosmetic application, preservatives remain active on our skin, potentially affecting the skin’s microflora with continuous use. (2) Certainly, employing them in elevated concentrations enhances their effectiveness in terms of preservation, but at the same time, it can pose toxicity risks for consumers. In contrast, when used in lower concentrations, microbial resistance may develop. (3)

In conclusion, it is safe to say that preservatives usage in cosmetics is essential for their maintenance. But it’s important to find the right balance taking in account also the effects they might have on our microflora.

References

  1. Preservatives (europa.eu)
  2. Effects of Cosmetic Preservatives on Healthy Facial Skin Microflora – PMC (nih.gov)
  3. Cosmetics Preservation: A Review on Present Strategies – PMC (nih.gov)