Challenge (Preservative Efficacy) Test

YOUSEN products have undergone the Challenge (Preservative Efficacy) Test to ensure microbiological safety. This test evaluates the effectiveness of the preservative system in the product formulation against microorganisms such as bacteria, yeast, and mold.

During the test, the product is exposed to specific microorganisms under controlled conditions, and the multiplication of these microorganisms is monitored over time. The results reveal whether the product remains microbiologically safe throughout its shelf life.

Thanks to the Challenge test, it is confirmed that YOUSEN products can be used safely, maintaining their formula integrity and hygienic structure even after opening.