Moisturisers Product Testing

The claim ‘moisturising’ in a cosmetic product cannot be taken for granted. Indeed, it needs to be substantiated by specific efficacy tests.

One of the most used cosmetological studies to assess the moisturising properties of raw materials and cosmetic formulations is corneometry, a method that can indirectly assess the water content of the most superficial skin layers. This test type is suitable for obtaining a measurement of both short- and long-term moisturisation. 

As regards lipophilic products like oils and ‘occlusive’ products creating and/or contributing to maintaining the skin’s hydrolipidic film, an effective method to assess moisturising power is the TEWL test. This test can also allow to evaluate the level of skin integrity, providing an index of skin barrier function recovery against water loss.

In addition, there are in vitro hydration measurements of dehydrated keratinocytes with saline solutions to assess the rehydrating power of the tested product. This can also be done by analysing aquaporin expression (aquaporins are the proteins that allow water into and out of cells). Lastly, it is important to point out that, even if raw materials are effective, the moisturising power of the ingredients may vary a lot based on the formulation of the finished product.