Peptides Lack Reliable Safety Information, Watchdog Warns Peptides take off as a DIY treatment but is that a good idea? : NPR 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 An FDA Reversal on Peptides Could Open the Market to Unsafe Drugs ProPublica