Safety of skincare products

Many consumers wonder how the safety of skincare products is assessed. In this article, we give you a few elements to help you understand what is written on the packaging of your skincare products.

Is this product safe? How was it assessed? How much should I believe of what is written on the packaging? All these questions, as well as others, are legitimate, and sometimes the answers are not that easy to find. Here are a few elements that can help you understand what lies behind a moisturizing product.

The European cosmetic regulation, set up in the summer of 2013, has strongly restricted the number of cosmetic products released on the market. A certain number of criteria, which were relatively lax before, have been better defined in the interest of the consumer. The safety of the skin care products, and allegations on the packaging are part of these criteria.

To understand better the assessment of the safety of skin care products, it is important to understand how this product was elaborated: when the formulation is set, a first batch of the product must pass a series of tests so as to determine how safe this product is. There are three strictly essential tests: stability, skin irritation, and challenge test.

Stability test

It is essential to understand the behavior of a product throughout its life. Products can has very long life spans (several years for a non opened product), and it is not possible to wait three years before launching a product on the market, simply to know if it will start to shift phases during this period of time. Models of accelerated ageing have been developed, so as to speed up the occurrence of a shifting of phases or of an oxidation for example, and estimate how long a product can be considered as stable. There are many variations, but in principle, they all consist in subjecting the product to high temperatures for several months (three months in general, but it can be more). Low temperature trials, and temperature cycle trials can also give information on the stability of products. There are no standardized regulated tests, and the expertise of the laboratory in charge of these tests is therefore essential to lead the best possible tests.

Challenge test

This test is essential to determine the security of the product preservation. It is based on the deliberate introduction in the product of a known quantity of bacteria, mold and yeast, and on the follow up of how they disappear in time (during a month). If the preservation system is effective, almost all micro-organisms must have been eliminated during the first week. Different parameters can influence the disappearance speed of the micro-organisms, but in all cases, they must have disappeared so that a product can be sold.

Skin irritation test

Also called patch test, it involves applying a product on the skin of a volunteer, and leaving it under an occlusive layer during 48 hours. At the end of this period of time, an exam under medical control is done to determine if there has been a skin reaction.

A last test, the eye irritation test, is also necessary for all products that can be in contact with eyes. Typically, moisturizing products enter this category. Animal testing is now strictly forbidden to test the safety of skin care products. New in vitro models have therefore been developed. They consist in putting cellular models in contact with the product, and determining the level of irritation induced by this contact.

Other tests

Other tests are available, and can be used by the manufacturer to add specific allegations on his packaging. For example, if the competent authorities request it, he must supply proofs demonstrating a moisturizing or soothing effect, or that the product is hypo-allergenic…

Currently, there are no defined regulated tests, and many are based on the experience of the different actors of the sector.


Once all these tests are done, a file is handed to a toxicology expert, who is generally independent. This document describes the exact composition of the product, and also includes different attestations (purity and origin of raw materials, dosage of certain molecules…). From the exact formulation of the product, and the quantity generally applied on the skin (quantity of the product, surface of the skin on which the product is applied), the toxicology expert is able to determine the dose which is absorbed by a person, and to compare it with doses which are generally accepted. A safety factor is applied to this equation, a factor which depends on the target of the product (for example, this factor is clearly more important if the product is intended for a child, compared to the norms applied for an adult).

The toxicology expert is therefore able to determine the safety of the product for the population for which this product is intended, and is also capable of emitting an opinion on the adequacy between the allegations on the packaging of a product and the proofs brought by the laboratory to support these allegations.

All these elements are deposited in a document called the cosmetic file. A laboratory must not transmit this document before a product is released on the market, but it must be available if competent authorities request it.

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