The peptide problem: Hype is outrunning the evidence 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 Deep Dive: Regulatory Status of Popular Compounded Peptides Holt Law Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance[v3] Preprints.org