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Regulation

How U.S. law treats peptides: what FDA regulates, why 'research use only' is not a legal shield, how compounding lists work, and what the 2026 policy changes did. Every explainer cites the statute, regulation or agency record.

Hub reviewed by Amino Wire Editorial Team · October 19, 2026

In short

Peptides in the US fall into three legal lanes: FDA-approved drugs (prescription only), compounded drugs (legal when a licensed pharmacy follows 503A or 503B rules), and 'research use only' products, which FDA treats as unapproved new drugs when they are marketed for human use. These explainers set out each lane with its sources.

Explainers

14 pages

  1. Legality

    Are peptides legal? What US law actually says in 2026

    Are peptides legal in the US? Prescription peptides, compounded peptides, 'research use only' peptides and sport rules, with FDA, DOJ and court sources.

  2. FDA compounding categories

    FDA Category 2 peptides: the list, the reasons, and the 2026 changes

    Which peptides FDA put in 503A/503B Category 2, the safety reasons it gave, which were withdrawn in 2026, and what Category 2 does and does not mean.

  3. Compounding law

    503A vs 503B: the two legal lanes for compounded peptides

    The difference between 503A pharmacies and 503B outsourcing facilities, the bulk-ingredient rules, and why they decide whether a peptide can be compounded.

  4. Labels & intended use

    ‘Research use only’: what the label does, and what it doesn’t

    Why 'research use only' and 'not for human consumption' labels don't protect peptide sellers: the intended-use rule, FDA letters and a DOJ plea, explained.

  5. Compound status

    Is BPC-157 legal? Its FDA status, step by step

    Is BPC-157 legal in the US? Not FDA-approved, out of Category 2 since April 2026, backed by FDA advisers in July, awaiting an interim policy.

  6. Enforcement

    FDA warning letters to peptide sellers: what they are and how to read one

    What an FDA warning letter is, what it is not, how to find and read one, and the pattern in letters to peptide sellers from December 2024 to August 2026.

  7. Imports & customs

    Importing peptides: what FDA’s import rules say

    How FDA treats imported peptides: the personal importation policy and its limits, detention and refusal, and why 'research' labels don't change the analysis.

  8. GLP-1 compounding

    Compounded semaglutide and tirzepatide after the shortages ended

    How the end of the semaglutide and tirzepatide shortages changed compounding: dates, the 'essentially a copy' rule, and where research GLP-1s fit.

  9. Sport

    Peptides and anti-doping: which are banned under WADA’s 2026 list

    Which peptides WADA's 2026 Prohibited List covers: BPC-157 (S0), growth hormone secretagogues and GHRPs (S2), TB-500 and thymosin beta-4 derivatives.

  10. Reference table

    FDA status by peptide: approval, compounding category, advisory votes and sport

    One table for 25 peptides: FDA approval, 503A category, advisory committee votes and WADA status, checked against primary records on Oct 19, 2026.

  11. State law

    Peptide laws by state: what states can and can't change, and what's actually on the books

    How state law affects peptides: what states control, Louisiana's 2026 Act 374, Florida bills that died, and how to check your own state's records.

  12. FDA compounding categories

    FDA Category 1 peptides: which ones are on it and what Category 1 allows

    Which peptides are in FDA's 503A Category 1 (GHK-Cu non-injectable, glutathione, VIP), what Category 1 means for pharmacies, and why BPC-157 isn't on it.

  13. Process

    How a peptide gets on FDA's 503A bulks list: nomination, PCAC vote, rulemaking

    The steps from nomination to the 503A bulks list: FDA's four criteria, what the Pharmacy Compounding Advisory Committee does, and why a vote is not a rule.

  14. Pending policy

    FDA's 'Interim Access Policy' for compounded peptides: what is known and what it could mean

    What FDA's Interim Access Policy for Compounding Using Certain Peptides (RIN 0910-ZD94) is, its review status, enforcement discretion, and open questions.

Regulation FAQ

Are peptides legal in the US?

It depends on the product and how it is sold. FDA-approved peptide drugs are legal with a prescription; compounded peptides are legal only when a pharmacy follows section 503A or 503B rules; peptides sold online as "research use only" are treated by FDA as unapproved new drugs when marketed for human use.

What is FDA Category 2?

Category 2 is FDA's interim list of nominated compounding ingredients where it has identified significant safety risks. Pharmacies get no enforcement discretion to compound substances in it. Several peptides, including BPC-157, moved out of Category 2 in April 2026 after their nominations were withdrawn.

Does a "research use only" label make a peptide legal to sell?

No. Under 21 CFR 201.128, FDA judges intended use from everything a seller says and does, not just the label. When marketing points to human use, FDA treats the product as an unapproved new drug.

What is the difference between 503A and 503B compounding?

503A pharmacies compound for identified patients on a prescription and may use only certain bulk ingredients. 503B outsourcing facilities register with FDA, follow CGMP, and may compound without patient-specific prescriptions under their own bulk-ingredient rules.