The patch test is used to assess the skin tolerance of a cosmetic product and confirm that it does not cause irritation. This test, which is essential for the safety of products marketed in Switzerland and the European Union, involves applying small amounts of the formula to dermatological patches specially designed to maintain controlled and constant contact with the skin. These patches are then placed on the back or forearm of a panel of 10 to 20 volunteers representing different skin types, in accordance with European and Swiss regulatory requirements (OCos/OSAV).
The patches remain in place for 24 to 48 hours, during which time the tested area remains protected but in direct contact with the product. When they are removed, a dermatologist carefully examines the skin for any signs of intolerance: redness, irritation, itching, swelling, or allergic reactions. In some cases, a second check is carried out 24 to 72 hours later to identify any delayed reactions, which is particularly important for validating safety in accordance with Swiss and European standards.
The patch test is therefore an essential step in demonstrating the skin safety of a cosmetic product before it is placed on the market, and it is directly integrated into the DIP/PIF, which is mandatory in Europe and Switzerland.
Test on sensitive skin
Sensitive skin testing is designed to verify a product's tolerance on volunteers with particularly reactive skin that is prone to redness or discomfort. This analysis is highly valued in the Swiss market, where consumers and authorities demand solid evidence of a product's skin compatibility, particularly for natural or dermatological skincare products.
A panel of volunteers with sensitive skin is selected, and the product is applied according to a specific protocol: a single application, daily application, or repeated application over several days or weeks, depending on the product category being evaluated. Dermatologists regularly check the condition of the skin, looking for any tingling, burning, tightness, redness, or swelling. As with patch testing, post-exposure monitoring may be carried out to identify any delayed reactions. This test confirms that the product can be used without discomfort even by the most reactive skin types, providing an additional level of safety and confidence.