Peptides

Table of Contents

1. The Six Peptides (6)
2. What a Peptide Is
3. Approved Peptide Drugs and Unapproved Peptides
4. The 2026 Actions in Order
5. Forms and Routes Covered by the Interim Policy
6. The Advisory Committee Votes
7. Other Peptides on the Withdrawn List
8. How Much Human Evidence Exists
9. Key Research Papers
10. Connections
11. Featured Videos

The Six Peptides (6)

The six peptides listed in Appendix A of the October 2026 interim policy, each with its own page.

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What a Peptide Is

Amino acids join end to end through chemical links called peptide bonds. A short chain is called a peptide; a long chain that folds into a complex shape is called a protein. The dividing line is a convention rather than a law of chemistry, but United States drug regulation draws one: under the U.S. Food and Drug Administration’s regulations, a “protein” is a chain of more than 40 amino acids, so shorter chains are regulated as peptides and generally as ordinary drugs rather than as biological products.

The six peptides on these pages are all short. Lysine-Proline-Valine is three amino acids long and Epitalon four; Semax and the Thymosin Beta-4 Fragment are seven; Body Protection Compound-157 is fifteen; and Mitochondrial Open Reading Frame of the 12S rRNA-c is sixteen. Several are pieces or copies of natural molecules: Lysine-Proline-Valine is the last three amino acids of alpha-melanocyte-stimulating hormone, the Thymosin Beta-4 Fragment is a capped seven-amino-acid piece of the 43-amino-acid protein thymosin beta-4, Semax is built on a fragment of adrenocorticotropic hormone, and Mitochondrial Open Reading Frame of the 12S rRNA-c is a copy of a peptide encoded in the DNA of mitochondria.

Each peptide can be made as a free base (the peptide alone) or as an acetate (the peptide paired with acetic acid as a salt). The U.S. Food and Drug Administration treats the two as different bulk drug substances, which is why its advisory committee voted on each form separately.

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Approved Peptide Drugs and Unapproved Peptides

Many peptide medicines are approved drugs that went through clinical trials and U.S. Food and Drug Administration review of their manufacturing, among them the glucagon-like peptide-1 receptor agonists used for type 2 diabetes and weight loss. None of the six peptides on these pages is an approved drug in the United States, and the U.S. Food and Drug Administration’s briefing for Body Protection Compound-157 states that no product containing it is approved in any country.

Until 2026 these peptides reached people mainly in two ways: through compounding pharmacies, which prepare medicines for individual patients from bulk ingredients, and through products sold online labelled “for research use only.” In September 2023 the U.S. Food and Drug Administration placed them in its “Category 2” of bulk substances that may present significant safety risks in compounding, citing concerns such as immunogenicity (the risk of provoking an immune reaction) and peptide-related impurities. On 24 August 2026 the agency dated five warning letters to online sellers of injectable products labelled “research use only,” stating that the listed products “are unapproved new drugs”; those letters named other peptides, not the six on these pages. The interim policy of October 2026 gives as one of its reasons that it “will discourage the continued, widespread use of certain research-use-only peptides supplied by foreign manufacturers that pose a safety risk to US patients.”

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The 2026 Actions in Order

• September 2023: the six peptides placed in the U.S. Food and Drug Administration’s Category 2 for compounding under section 503A, according to the October 2026 policy document.
• 16 April 2026: the U.S. Food and Drug Administration announced a Pharmacy Compounding Advisory Committee meeting on seven peptides (91 FR 20465).
• 22 April 2026: the U.S. Food and Drug Administration’s Category 2 page updated; the peptides moved to a table of substances “nominated but withdrawn,” with their safety notes kept.
• 23–24 July 2026: the committee met. Agency reviewers proposed that none of the seven be listed; the committee voted to recommend six and voted against emideltide.
• 24 August 2026: five U.S. Food and Drug Administration warning letters to online sellers of other “research use only” injectable products.
• 30 October 2026: the U.S. Department of Health and Human Services interim enforcement-discretion policy published (91 FR 68526, docket HHS-OASH-2026-0496).
• 13 November 2026: public comment on the interim policy closed.

As of 14 November 2026 no proposed or final rule adding any of the peptides to the 503A Bulks List had been published. The full record is on U.S. Food and Drug Administration Review of Compounded Peptides Including BPC-157 (2026) and U.S. Department of Health and Human Services Interim Policy on Compounding Six Peptides (2026); the news summary is Six Peptides: The HHS Compounding Policy and Its Limits.

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Forms and Routes Covered by the Interim Policy

The interim policy covers each peptide in one form and for named routes only, and only when all ten of its conditions are met, including a certificate of analysis from a manufacturer registered with the U.S. Food and Drug Administration, one active ingredient per product, reporting of serious adverse events to the agency’s MedWatch program, and a valid patient-specific prescription.

The policy states that compounded drugs “are not FDA-approved,” and the Federal Register notice states that it “does not establish any rights for any person and is not binding on HHS or the public.” It does not place any peptide on the 503A Bulks List, and the department “may revisit” it if “a safety signal or product quality issue arises.”

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The Advisory Committee Votes

Counts read aloud for the record on the U.S. Food and Drug Administration’s webcast of the 23–24 July 2026 meeting (no written minutes or transcript had been posted as of 14 November 2026). Each peptide’s free base and acetate received the same count.

Advisory committees, in the U.S. Food and Drug Administration’s words, “make non-binding recommendations to the FDA, which generally follows the recommendations but is not legally bound to do so.”

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Other Peptides on the Withdrawn List

The U.S. Food and Drug Administration’s Category 2 page lists seventeen substances as “nominated but withdrawn.” Besides the six above and emideltide, they are AOD-9604, cathelicidin LL-37, CJC-1295, dihexa acetate, GHK-Cu (for injectable routes), ipamorelin acetate, mechano growth factor pegylated, melanotan II, selank acetate and thymosin alpha-1. None of these is covered by the October 2026 interim policy, and the page keeps the agency’s safety notes for each — for melanotan II, for example, published case reports of “serious adverse events including melanoma.” The agency’s categories list states that it intends to consult the advisory committee “before the end of February 2027” about GHK-Cu.

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How Much Human Evidence Exists

For all six peptides most of the published research is laboratory and animal work. The U.S. Food and Drug Administration’s reviewers found no human study at all of Lysine-Proline-Valine, the Thymosin Beta-4 Fragment or synthetic Mitochondrial Open Reading Frame of the 12S rRNA-c; the human studies of Mitochondrial Open Reading Frame of the 12S rRNA-c measure the body’s own peptide, not one given as a drug. For Body Protection Compound-157 they found two small studies of an enema lasting at most two weeks; for Epitalon one under-the-tongue study that did not measure sleep; and for Semax one meeting abstract and one small uncontrolled study, with Russian-language trials set aside because no English versions were available. Each peptide’s page lists the studies that exist, their size and design, and what they did and did not measure.

Two concerns the U.S. Food and Drug Administration raised for nearly every peptide are immunogenicity — peptides that clump together or carry closely related impurities from manufacture can provoke antibodies — and characterization, meaning whether a given batch can be shown to contain the right molecule at the right purity. The interim policy’s certificate-of-analysis condition is aimed at the second; the department describes the agency’s safety concerns as “mechanistic rather than observed” or “inferential rather than observed” for several of the peptides.

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Key Research Papers

1. Vasireddi N, Hahamyan H, Salata MJ, Karns M, Calcei JG, Voos JE, Apostolakos JM (2025). Emerging Use of BPC-157 in Orthopaedic Sports Medicine: A Systematic Review. HSS Journal 21(4):485-495 — PubMed PMID: 40756949
2. Mayfield CK, Bolia IK, Feingold CL, Lin EH, Liu JN, Rick Hatch GF, Gamradt SC, Weber AE (2026). Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians. American Journal of Sports Medicine 54(1):223-229 — PubMed PMID: 41476424
3. Lee C, Zeng J, Drew BG, Sallam T, Martin-Montalvo A, Wan J, Kim SJ, Mehta H, Hevener AL, de Cabo R, Cohen P (2015). The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance. Cell Metabolism 21(3):443-454 — PubMed PMID: 25738459

Each peptide page carries its own list of verified research papers.

PubMed Topic Searches

1. PubMed: therapeutic peptides and immunogenicity
2. PubMed: peptide drugs and compounding
3. PubMed: research-use-only peptides and purity

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Connections

• Drugs
• Pharmacology
• Six Peptides: The HHS Compounding Policy and Its Limits
• U.S. Department of Health and Human Services Interim Policy on Compounding Six Peptides (2026)
• U.S. Food and Drug Administration Review of Compounded Peptides Including BPC-157 (2026)
• U.S. Food and Drug Administration Proposal on Compounded Semaglutide and Tirzepatide (2026)
• Glucagon-Like Peptide-1 Receptor Agonists
• C-Peptide
• Longevity Protocols
• Amino Acids

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