GENETIC analyses of human skin are revealing more about what makes us look old. As well as throwing up ways to smooth away wrinkles, the studies may provide a quantifiable way to test claims made for skin products.
In the past, cosmetics companies relied on subjective assessments of skin appearance, and changes in its thickness, colour and protein composition, to evaluate the effectiveness of their products and work out the quantities of ingredients needed to get the best results. “It was totally hit and miss,” says Rosemary Osborne of Procter and Gamble in Cincinnati, Ohio.
Now skin researchers, including those at P&G, are starting to use DNA microarrays, common in the drugs industry, to measure the expression of thousands of genes in skin of different ages. “It’s a way of finding mechanisms that were not known before,” says Fernand Labrie, who studies skin genomics at Laval University in Quebec City, Canada.
Identifying a “genetic signature” of younger skin should also provide a benchmark for testing existing skin products. For example, P&G is measuring the effects on gene expression of a skin cream ingredient called pal-KT. Previous approaches suggested it increased production of structural skin proteins like collagen and laminin. Gene analysis indicates it also affects the expression of genes involved in wound healing.
Rigorous studies in people are needed to confirm that changing gene expression in older skin to match younger skin improves skin quality. “You could find that a molecule is up or down-regulated, but whether that relates to a consumer noticing a difference is a big jump,” says Diona Damian at the University of Sydney, Australia.
If new tools become available for assessing skin products, this could force cosmetics companies to back up claims about their products with hard evidence.
