Peptides are naturally occurring amino acids that are the building blocks used to make proteins in our skin, explains Joyce Imahiyerobo-Ip, MD, FAAD, founder and CEO of Vibrant Dermatology and Skin

Bar MD. "Collagen, for example, is made up of three polypeptide chains," she says. "Adding peptides to skincare products has many benefits, including stimulating collagen production, improving skin barrier function, improving skin's elasticity, and decreasing inflammation in the skin."

And not all peptides are the same, there are different types used in skincare. Tiffany Libby, MD, FAAD, Reserveage's resident dermatologist, says when applied topically, the peptides act as little messengers and instruct the skin cells to perform functions like building collagen and elastin, reducing inflammation, and maintaining hydration.

"The main groups are signaling peptides, enzyme-inhibiting peptides, carrier peptides, and neurotransmitter-inhibiting peptides," Libby says. "Signaling peptides work to stimulate new collagen and elastin production. Enzyme-inhibitor peptides block the enzymes that break down or degrade collagen. Carrier peptides deliver minerals to the skin that are essential for specific enzymatic processes like cross-linking collagen and wound healing. Neurotransmitter inhibitor peptides work similarly to neurotoxins like Botox, but with lower efficacy to reduce wrinkle formation."