Before a cosmetic product is brought to market, it undergoes numerous tests to verify its safety and long-term stability. All of these tests are mandatory to ensure that the product is safe for consumers.
Additional tests are also required to substantiate the product’s claims.
Stability testing:
However, there are two ways to verify the stability of a cosmetic product:
The real-time method is rarely used in the industry because it takes too long during the cosmetic product development process.
Accelerated aging is more widely used. For this method, the product is placed in a glass container. The samples are then subjected to different conditions:
- At room temperature in the dark,
- At room temperature in the light,
- At 4°C, At 40°C, At 50°C,
The product is then analyzed at various time points: Day 0, Day 1, 1 week, 2 weeks, 1 month, 2 months, 3 months… The parameters observed are: appearance, color, pH, odor, and viscosity.
Compatibility test:
The compatibility test verifies that the container does not interact with the product and that its stability is not affected. Thus, after conducting the stability test on the product alone, its stability in the final package must be verified. This test is conducted under the same conditions as the stability test but in the final package.
The parameters assessed are: color, odor, weight, appearance of the contents and the container, effectiveness of the closure system, and leak-tightness of the closure system.
Challenge Test:
The purpose of the Challenge Test is to determine whether your product is likely to allow the growth of pathogenic or potentially pathogenic bacteria, such as Listeria monocytogenes, Bacillus cereus, or Staphylococcus aureus
A preservative system is included in most cosmetic product formulations to protect them from microbiological contamination during normal consumer use and to maintain the product’s quality and safety. The objective of the Challenge Test is to demonstrate the effectiveness of the preservative system throughout the cosmetic product’s shelf life and period of use. This is a mandatory regulatory requirement aimed at reducing risks to consumer safety.
Patch test:
Widely used in cosmetics, this is a simple and rapid test to assess skin tolerance. For this test, patches containing the products to be tested are applied to the backs of volunteers for 48 hours. The laboratory then observes any reactions: erythema (primarily) or edema (rarely). This test is conducted under dermatological supervision.
Eye irritation:
Eye irritation tests are important for evaluating the safety of cosmetic products before they are placed on the market. Unlike the skin patch test, these tests are performed on in vitro cell culture models. Conducted in accordance with current standards, they ensure that the products will not cause damage to the human eye in the event of accidental contact.
Two commonly used in vitro methods for testing eye irritation are the neutral red release method and agarose gel diffusion. These techniques aim to replicate the conditions under which a product comes into contact with human eye cells.
The User Test:
This test is used to evaluate the product under normal conditions of use. After being briefed on the product and how to use it, the tester will use the product “at home” in accordance with normal conditions of use. After a specified period, the tester returns to the research laboratory to complete a questionnaire about the product. The tester is asked for their opinion on the product’s performance and their experience with it. This opinion remains highly subjective.
Efficacy test:
Like the usage test, this is also conducted on a panel. However, after using the product, the tester returns to the laboratory to undergo measurements.
The efficacy test provides quantitative data collected by a measuring device and is therefore purely objective (for example: the corneometer for measuring hydration, the sebometer for measuring sebum levels).
The mandatory tests listed above were conducted on the formulas featured in the Néo Cosmétique catalog: https://www.neo-cosmetique.fr/pages/produits
Sources:
- ISO 29621 standard
- ISO 11930-2019 standard
- https://www.groupe-cca.com/etudes-de-tolerance-et-defficacite-in-vivo/irritation-oculaire/