What are peptides? 

Peptides are short chains of amino acids that occur naturally in the skin and are the building blocks of proteins. In cosmetic products (or skin-care products), peptides can mimic the protein sequences in collagen and elastin and stimulate production, says Geeta Yadav, MD, a dermatologist and founder of Skin Science Dermatology in Toronto. These are the proteins that keep skin looking youthful. “Many peptides are small enough to penetrate the skin,” says Blair Murphy- Rose, MD, a dermatologist at the Laser & Skin Surgery Center of New York and clinical instructor of dermatology at Weill Cornell Medical College. As a result, they’re able to have a more profound impact than skin-care formulas containing larger molecules that simply sit on the skin’s surface. 

What do peptides do? 

“In skincare, peptides are best known for stimulating skin repair and inhibiting the signs of ageing,” explains Dr Yadav. And they don’t have the irritating effects that more potent anti-ageing ingredients, like retinoids, can have. Peptides generally work by telling other cells to perform tasks like increasing the production of collagen or elastin. This is essential because the body’s own production of collagen and elastin starts to decline after the age of 20. Peptides also support a healthy skin barrier and promote the healing of wounds; some even have a mild Botox-like effect that will relax muscles and treat fine lines, adds Dr Murphy-Rose.

How do you use peptides? 

Lots of anti-ageing formulas are packed with peptides. The best thing about them is that they play well with active ingredients, say Gloria Lu and Victoria Fu, skin-care chemists and cofounders of Chemist Confessions Inc. You’ll see them paired with vitamin C, hyaluronic acid, and niacin. It’s most important to use products that have long-lasting contact on the skin—they give the peptides enough time to go to work, says Dr Murphy-Rose. So opt for serums and moisturizers as opposed to cleansers.