In the 1980s, Dr. Albert Kligman, an American dermatologist made an interesting observation. Patients being treated for acne with retinoic acid saw an improvement in their wrinkles, an improvement that was eventually traced to enhanced collagen formation. But there was a but. There were hurdles on the road to smooth skin. Retinoic acid treatment resulted in increased sensitivity to sunlight, and initially, in irritated skin. To ensure that patients were properly monitored, retinoic acid was made available only by prescription. But cosmetic producers are free to include other forms of vitamin A, such as retinol, in face creams. At the concentrations used, however, the effect of retinol is minimal.
Pentapeptides, now heavily marketed as anti-wrinkle agents, emerged from a study on wound healing. Researchers investigating the nature of the chemicals used by cells to trigger the formation of collagen identified these messengers as short chains of five amino acids, in other words, “pentapeptides.” Laboratory studies of skin tissue soon showed that collagen formation could indeed be enhanced, but there was a question of pentapeptide absorption through the skin. Linking the pentapeptides to a fatty acid such as palmitic acid yielded absorbable “palmitoyl pentapeptide,” the “active” ingredient in many an anti-wrinkle cream. The claim is that constant use over twelve weeks results in firmer, more youthful skin. Maybe so. If you look with a microscope.
Glycosaminoglycans, usually referred to as GAGs, are naturally occurring compounds that help the skin retain moisture and resilience. Can their production be increased? Apparently, xylose, a simple sugar, can stimulate the production of GAGs. The problem is delivering it to the appropriate cells. Just adding xylose to creams won’t do, but xylose precursor compounds that can be absorbed from creams have been developed. Once inside cells, these yield xylose, which in turn fires up GAG formation. This is not just theory, skin biopsies actually show increased amounts of GAGs. But does this translate to improved appearance? In a double blind clinical trial, treatment with a xylose releasing cream resulted in better skin elasticity, less dryness, fewer age spots and reduced wrinkles. The problem, though, is that these measurements are made by technicians using sophisticated instruments. Whether the difference is going to cause heads to turn is debatable.
Also debatable is the effectiveness of antioxidants in creams. In theory, they should do something. In practice, there is no compelling evidence that they do. The newest players in the antioxidant sweepstakes are “nanoparticles” composed of “fullerenes,” molecules made of sixty carbon atoms joined together in the shape of a soccer ball. Indeed, fullerenes are effective at neutralizing free radicals, but safety questions have been raised about what nanoparticles may do when absorbed into the body. Probably about as much as they do in a cream.