Here are five commonly listed active ingredients, and the scientific evidence about whether they may play a role in decreasing signs of aging.
As you age, your skin becomes thinner and loses fat, causing it to sag and develop fine lines . The body produces less collagen and elastin, substances that enables the skin to maintain its smooth, plump and youthful appearance.
Peptides are small proteins that help stimulate new cells to grow and help skin cells to heal.
"The jury is still out on how beneficial they are," said Dr. Ivona Percec, a plastic surgeon who specializes in cosmetic surgery and skin care at the University of Pennsylvania. "We don't know for sure what the biological benefits are."
Although peptides are found in a number of products, experts still aren't sure exactly which formulation may work. "If they work, they do so by stimulating the replacement of collagen, elastin, and other components that suffer during aging," Percec said. "The concern is that peptides are large molecules, and depending on their formulation and the skin surface, they may not be able to penetrate deeply enough to achieve their effect.