United States peptide regulation

Peptides in the United States are regulated primarily by the FDA under the Federal Food, Drug, and Cosmetic Act (FDCA). Approval does not by itself make every peptide product prescription-only: marketing category is specific to the product, formulation, route, and indication. For example, some topical bacitracin- or polymyxin-B-containing combination products are marketed OTC, whereas reviewed injectable, ophthalmic, and many other peptide products are prescription medicines. Unapproved "research peptides" marketed for human use are unapproved new drugs. Compounding of peptides is subject to Sections 503A and 503B of the FDCA, with heightened scrutiny on GLP-1 receptor agonists since 2024–2026.

• FDA: drug approval (NDA, ANDA, 505(b)(2), BLA), compounding oversight, import enforcement, warning letters, CGMP inspections.

• FTC: jurisdiction over false or misleading advertising of drugs (FTC Act §5, 15 USC §45).

• DEA: scheduling under the Controlled Substances Act (21 USC §801 et seq.); most therapeutic peptides are not scheduled.

• CBP: enforces FDA import decisions at ports of entry.

Key statutes:

• FDCA §505 (21 USC §355) — new drug approval requirement.

• FDCA §503A (21 USC §353a) — traditional compounding exemptions.

• FDCA §503B (21 USC §353b) — outsourcing facility compounding.

• FDCA §301 (21 USC §331) — prohibited acts.

• 21 USC §321(g)(1) — definition of "drug".

• 21 CFR Part 210–211 — CGMP.

• 21 CFR Part 314 — NDA/ANDA procedures.

• 21 CFR Part 216 — 503A bulks list.

FDA-approved peptide drugs include:

• GLP-1 receptor agonists: semaglutide (Ozempic, Wegovy, Rybelsus), liraglutide (Victoza, Saxenda), tirzepatide (Mounjaro, Zepbound), dulaglutide (Trulicity), exenatide (Byetta, Bydureon), lixisenatide (Adlyxin).

• Insulins (regulated as biologics under BLA since March 2020): insulin glargine, lispro, aspart, degludec, and others.

• GnRH analogues: leuprolide (Lupron), goserelin (Zoladex), and triptorelin. An FDA substance record for buserelin does not establish product approval; no buserelin product was identified in Drugs@FDA for this review.

• Somatostatin analogues: octreotide (Sandostatin), lanreotide.

• Other: teriparatide (Forteo), calcitonin (Miacalcin), desmopressin, vasopressin, setmelanotide (Imcivree), bremelanotide (Vyleesi), linaclotide (Linzess), plecanatide (Trulance).

Source: FDA Orange Book, https://www.accessdata.fda.gov/scripts/cder/ob/

Investigational peptides require an IND (21 CFR Part 312) before clinical testing in humans. IND sponsors must submit preclinical data, manufacturing information, and clinical protocols. FDA must authorise the IND before human trials begin.

Section 503A (traditional compounding):

• Patient-specific prescription required.

• Must use bulk drug substances that are USP/NF compendial, components of FDA-approved drugs, or on the 503A bulks list (21 CFR §216).

• Exempt from FDA approval and full CGMP.

• Distribution across state lines limited.

Section 503B (outsourcing facilities):

• Voluntary FDA registration.

• Must comply with CGMP.

• The statutory bulk-substance condition generally requires either that the bulk drug substance appear on FDA's 503B Bulks List or that the drug product compounded from the bulk substance appear on FDA's drug-shortage list at the time of compounding, distribution, and dispensing. FDA also maintains a separate, conditional interim enforcement policy for certain nominated Category 1 substances; a nomination or category placement is not inclusion on the statutory list.

• Preliminary Federal Register notice (published May 1, 2026, 91 FR 23431; document 2026-08552): FDA proposed not to include semaglutide, tirzepatide, or liraglutide on the 503B Bulks List after tentatively finding no clinical need for outsourcing facilities to compound from those bulk substances. A June 26, 2026 notice extended comments through July 30, 2026. As of this page's August 6, 2026 review, no final Federal Register determination was identified. The preliminary notice does not itself decide every lawful-compounding question, and the separate drug-shortage pathway and all other section 503B conditions must be assessed on current facts.

  Official proposal record: https://www.federalregister.gov/d/2026-08552

Source: https://www.fda.gov/drugs/human-drug-compounding/human-drug-compounding-laws

Compounded drugs are not FDA-approved. The FDA has issued multiple risk alerts on dosing errors with compounded injectable semaglutide (July 26, 2024).

• Import: Unapproved peptides are subject to detention without physical examination under Import Alert #66-78. FDA personal importation policy generally does not cover "research peptide" imports for personal use.

• Sale: Unapproved new drugs in interstate commerce violate FDCA §505 and §301.

• Advertising: FTC Act §5 prohibits false or misleading claims. In June 2026, FDA issued a warning to telehealth companies about false claims for compounded GLP-1 peptides (FDA telehealth page).

• Online: FDA and FTC jointly target peptide vendors that market via social media and e-commerce platforms.

Labelling a product "for research use only" or "not for human consumption" does not exempt it from the FDCA if the seller knows or should know the product is intended for human use. The definition of "drug" (21 USC §321(g)(1)) turns on intended use, not label wording. FDA has issued numerous warning letters to peptide vendors under this theory.

Source: FDA Unapproved Drugs Initiative, https://www.fda.gov/drugs/enforcement-activities-fda/unapproved-drugs

WADA Prohibited List S2 covers peptide hormones, growth factors, and related substances. USADA enforces WADA rules for US athletes. See WADA and sport.

• May 1, 2026: FDA published its preliminary proposal not to include semaglutide, tirzepatide, or liraglutide on the 503B Bulks List.

• 2024–2026: Multiple warning letters to compounders of semaglutide and tirzepatide for using non-compliant bulk drug substances.

• 2024–2026: Warning letters and seizure actions against research peptide vendors (BPC-157, TB-500, AOD-9604, melanotan II).

• Uncertainty: State-level actions on peptide scheduling vary (e.g., some states have scheduled melanotan II under state controlled-substance law). The scope of the "essentially a copy" restriction on compounded peptides under FDCA §503A remains subject to FDA enforcement discretion.

This is general regulatory research, not legal advice. Classification can turn on composition, claims, intended use, route, supplier role, and facts not captured by a product name.

1. FDCA §505, 21 USC §355. https://www.fda.gov/regulatory-information/laws-enforced-fda

2. FDA Compounding Laws. https://www.fda.gov/drugs/human-drug-compounding/human-drug-compounding-laws

3. FDA Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/

4. FDA Import Alerts. https://www.accessdata.fda.gov/cms_ia/importalert_189.html

5. 21 CFR Part 216. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-C/part-216

6. FDA Warning Letters. https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/compliance-actions-and-activities/warning-letters

7. FDA Alert on Compounded Semaglutide (July 2024). https://www.fda.gov/drugs/human-drug-compounding/fda-alerts-health-care-providers-compounders-and-patients-dosing-errors-associated-compounded

8. FDA Telehealth Companies Guidance (June 2026). https://www.fda.gov/drugs/human-drug-compounding/fda-telehealth-companies-what-know-when-promoting-compounded-drugs

9. DEA Schedules. https://www.deadiversion.usdoj.gov/schedules/schedules.html

10. FTC Act. https://www.ftc.gov/legal-library/browse/statutes/federal-trade-commission-act

11. FDA. Bulk Drug Substances Used in Compounding Under Section 503B of the FD&C Act. https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503b-fdc-act

12. FDA. List of Bulk Drug Substances for Which There Is a Clinical Need Under Section 503B of the FD&C Act; preliminary notice, 91 FR 23431 (May 1, 2026), FR Doc. 2026-08552. https://www.federalregister.gov/d/2026-08552

13. FDA. Extension of comment period for the May 1, 2026 notice, FR Doc. 2026-12937 (published June 26, 2026). https://public-inspection.federalregister.gov/2026-12937.pdf