Peptide therapy
Clinical reviewer: Jacob Moore, MD · Last checked September 22, 2026
What is peptide therapy?
Peptide therapy is the use of amino-acid chain compounds for medical or performance purposes, spanning FDA-approved medications and unapproved compounded or research-grade peptides sold directly to patients. Approved peptide drugs undergo FDA review of safety and effectiveness; unapproved peptides operate in what one 2026 review calls a "gray market," largely outside regulatory oversight.
What counts as peptide therapy?
FDA classes any amino-acid chain of 40 or fewer amino acids as a peptide rather than a protein [1], so peptide therapy spans everything from FDA-approved medications to compounded growth-hormone peptides and research-labeled products sold online. A 2026 review notes several peptide drugs "have undergone rigorous approval processes that evaluate both safety and efficacy," while "novel, unapproved compounds have emerged and are rapidly expanding into preventive medicine and performance enhancement" [2].
How does peptide therapy differ between approved and unapproved products?
An approved peptide drug carries FDA-reviewed labeling: doses, indications and monitored side effects. Unapproved peptides sold as compounded or research products have no such label. A 2026 Sports Medicine review found many unapproved peptides "demonstrate favorable tissue repair and metabolic outcomes in animal models, but rigorous human safety data are scarce, and there is potential for serious harm to patients" [3], describing that market as operating "largely outside of regulatory oversight" [3].
How can a pharmacy lawfully compound a peptide?
Under section 503A, a pharmacy may compound with a bulk substance only if it complies with an applicable USP or NF monograph, is a component of an FDA-approved drug, or appears on FDA's 503A bulks list when no monograph exists and the substance is not a component of an approved drug [4]. While FDA evaluates nominated substances, its interim policy sorts them into three categories; Category 1 substances "may be eligible for inclusion on the 503A bulks list" and remain under an interim enforcement policy until FDA decides [4].
Related terms
Sources
- FDA — The "Deemed To Be a License" Provision of the BPCI Act, Questions and Answers (Guidance for Industry, March 2020)
- Renke G, Chinellato L. Therapeutic Peptides in Aesthetic, Metabolic and Endocrine Conditions, Effects, Safety, Clinical Applications, and Future Perspectives. Int J Mol Sci, 2026.
- Mendias CL, Awan TM. Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance. Sports Medicine, 2026.
- FDA — Bulk Drug Substances Used in Compounding Under Section 503A
This entry is for education and is not medical advice. Talk with a licensed clinician about your own situation before starting, stopping, or changing any treatment.
