Injectable weight-loss medications, GLP-1s, have quickly become part of life for many people, bringing new attention to a class of compounds known as peptides. As interest grows, so does the importance of separating established science from social media hype. Peptides play a role in regulating processes from metabolism and sleep to joint recovery and skin health — but what exactly are they? “Peptides are short chains of amino acids that function primarily as signaling molecules in the body,” says Dr. Joe Upton, a board-certified antiaging physician at Lévy Aesthetics. “They essentially tell cells how to respond and help regulate key biological processes.” Some peptides are already well established in medicine. Insulin, for example, has been used for decades to regulate blood sugar, and newer peptide-based drugs like GLP-1 agonists are now widely prescribed for diabetes and weight management.…