Scroll through SkinTok long enough and you’ll hit a flood of videos hyping exosome therapy, exosome serums, and exosome treatments promising the skin health of a cherub. Exosomes are a part of the body’s internal messaging system, regulating everything from cell growth to hormone production and gene expression. Now, exosomes are in moisturizers, serums, and hair injectables, promising to repair your skin barrier, boost collagen production, and reverse aging. Most published clinical studies on exosome skin care are small-scale or lack rigorous controls. “The U.S. Food and Drug Administration has issued warnings about the misuse of unapproved exosome products, and as a practitioner, that raises a red flag.