Sources: U.S. Food and Drug Administration (FDA) Compounding and the FDA (503A & 503B guidance) FDA warning letters on unapproved peptide products National Institutes of Health (NIH) PubMed BPC 157: Miracle Healing Peptide or Hidden Danger? Regulatory Alert: FDA's April 2026 Update on BPC 157 and GHK Cu Holt Law The U.S. Food and Drug Administration is moving toward allowing compounding pharmacies to produce more than a dozen injectable peptides that were banned because of potentially significant safety risks, the New York FDA to weigh easing limits on unproven peptides promoted by RFK Jr.