Some peptides are FDA approved drugs. Some are legal supplements. Some are neither. The same word, peptide, covers all three categories. The regulatory status of the specific compound is what determines legality. What Peptides Are Legal in the U.S.? Understanding FDA Approval, Compounding, and the Legal Gray Areas Holt Law FDA Targets GLP 1 and Peptide Compounding, Advertising and 'Research Use Only' Labeling BPC 157: Miracle Healing Peptide or Hidden Danger?