More oversight needed of unapproved medicines that threaten patients' health PhRMA FDA releases denial letters for unapproved drugs, a step toward transparency 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 Indictment of Osteopathic Physician Signals Shift in Peptide Enforcement Stevens & Lee