FDA-Approved Peptide Drugs: What Approval Means and What It Does Not

Every published list of FDA-approved peptides opens with insulin. By the FDA's own regulatory definition, insulin is not a peptide.

The agency settled the boundary in a final rule effective March 23, 2020: a protein is "any alpha amino acid polymer with a specific, defined sequence that is greater than 40 amino acids in size."^[12] Insulin runs 51 residues. It is a protein, it is regulated as a biological product, and the applications that once made it a drug approval were converted to biologics licenses on the day that rule took effect.

That is not a quibble about vocabulary. It decides which molecules belong on the list at all, which is why published counts of approved peptide drugs disagree with each other by a factor of two. The answer to whether the FDA approves peptides is still an unambiguous yes, dozens of times over, most recently in September 2025. The harder questions are which ones, how they are counted, and why almost none of the compounds discussed in the research-peptide market appear among them.

Research content. The article below describes the regulatory status of peptide drug products under United States law. It is not legal advice and is not medical advice. Compounds sold by Peerless Peptides are sold for laboratory research use only and are not approved by the FDA for human or veterinary administration.

Last reviewed: September 19, 2026 by Peerless Research.

Summary

Dozens of peptide drugs hold FDA approval, spanning metabolic disease, oncology, rare genetic conditions, pain, and infectious disease. Published reviews count more than 80 peptide drugs on the market worldwide, though no official FDA tally exists and the figure depends on where an author draws the line between a peptide and a protein.^[3][4] The FDA drew that line at 40 amino acids in 2020, and most published lists ignore it.^[12]

Approval is a specific legal status attached to a specific application for a specific formulation. It is not a property of a molecule in the abstract. The consequence is that a molecule can appear on the approved list and also circulate as an unapproved research chemical, and the two are different articles of commerce even when the chemical name matches.

Three statuses are routinely conflated in popular coverage: approved drug, substance eligible for pharmacy compounding, and research chemical sold for laboratory use. The July 2026 advisory committee vote on seven peptides produced a wave of coverage that blurred the first two. This article separates them, and lists what is actually approved, with every date traceable to an application in the FDA's Drugs@FDA database.^[1]

Note: the approval dates below were retrieved from the openFDA Drugs@FDA interface on September 19, 2026, and reflect the earliest original application marked approved for each substance. Where a drug predates the electronic record, the database date can be later than first clinical use.

Three Statuses That Get Confused

An approved drug has been through a new drug application or a biologics license application. A sponsor submitted evidence, the FDA reviewed it, and the agency approved a defined formulation for a stated indication under an approved label. The approval attaches to the application, not to the chemical.

A substance eligible for compounding may be used by a state-licensed pharmacist as a starting material for a patient-specific prescription under Section 503A of the Federal Food, Drug, and Cosmetic Act. Eligibility runs as a cascade at 21 U.S.C. 353a(b)(1)(A): a substance with an applicable USP or NF monograph must comply with it; where no monograph exists, the substance must be a component of an FDA-approved drug; and only where neither holds does the bulk drug substances list at 21 CFR 216.23 govern.^[11] Compounded preparations are not approved drugs, and the pathway is described in our 503A and 503B primer.

A research chemical is supplied for laboratory use and is not an approved drug, not a compounded preparation, and not authorized for human or veterinary administration. This category is governed by the drug-definition statute at 21 U.S.C. 321(g)(1) and the objective-intent standard at 21 CFR 201.128 rather than by the approval or compounding provisions.

These are three different determinations made by three different mechanisms. A substance can occupy one, two, or none of them, and movement in one category implies nothing about the others.

Where the Peptide Ends and the Protein Begins

The FDA had to fix a boundary because Congress made one necessary. The Biologics Price Competition and Innovation Act moved protein products out of the drug-approval pathway at section 505 of the Federal Food, Drug, and Cosmetic Act and into the biologics licensing pathway at section 351 of the Public Health Service Act. Doing that required the agency to say what counts as a protein.

Its final rule, published February 21, 2020 at 85 FR 10057 and effective March 23, 2020, defines the term: "any alpha amino acid polymer with a specific, defined sequence that is greater than 40 amino acids in size."^[12] Above 40 residues, a molecule is a protein and is licensed as a biological product. At 40 or below, it is not, and it stays in the drug pathway.

On the date that rule took effect, approved applications for products above the line were deemed to be biologics licenses rather than drug approvals. The conversion is visible in the database: the Drugs@FDA record for tesamorelin, a 44-residue analog approved in November 2010, carries its application number today under a biologics license prefix rather than a new drug application prefix.

Molecule	Residues	Side of the FDA line
insulin (human)	51	protein, licensed as a biological product
tesamorelin	44	protein, licensed as a biological product
exenatide	39	peptide
tirzepatide	39	peptide
enfuvirtide	36	peptide
teriparatide	34	peptide
semaglutide	31	peptide
sermorelin	29	peptide

Two consequences follow. The first is that any list opening with insulin is counting a biological product, which is defensible under the chemists' convention of a 50-residue ceiling but not under the regulatory definition. The second is that the 40-residue line runs directly through the incretin class: exenatide and tirzepatide sit one residue below it.

The scientific literature has never agreed on a single number, and the FDA rule does not purport to be a taxonomy for biochemistry. It is a regulatory boundary for one statutory purpose. That is exactly why counts of approved peptide drugs vary so widely, and why a count is only meaningful alongside the definition it used.

What Is Actually Approved

The table below lists approved peptide drugs by International Nonproprietary Name, with the date of the earliest original application marked approved in Drugs@FDA. Brand names are omitted deliberately. Indications are given as stated in current FDA labeling.^[2]

Generic name	First approved	Approved use, per FDA labeling
insulin (recombinant human) †	Oct 28, 1982	diabetes mellitus
desmopressin	Feb 21, 1978	diabetes insipidus, nocturnal enuresis
calcitonin (salmon)	Apr 17, 1978	postmenopausal osteoporosis, hypercalcemia
octreotide	Oct 21, 1988	acromegaly, carcinoid and VIPoma symptoms
leuprolide	Apr 9, 1985	advanced prostate cancer, endometriosis
goserelin	Dec 29, 1989	prostate and breast cancer, endometriosis
sermorelin †	Dec 28, 1990	see note below (approval since withdrawn)
ganirelix	Jul 29, 1999	prevention of premature LH surges in fertility treatment
cetrorelix	Aug 11, 2000	prevention of premature LH surges in fertility treatment
bivalirudin	Dec 15, 2000	anticoagulation in coronary intervention
teriparatide	Nov 26, 2002	osteoporosis at high fracture risk
enfuvirtide	Mar 13, 2003	HIV-1 infection, in combination therapy
secretin	Apr 4, 2002	diagnostic stimulation of pancreatic secretions
ziconotide	Dec 28, 2004	severe chronic pain via intrathecal infusion
exenatide	Apr 28, 2005	type 2 diabetes mellitus
lanreotide	Aug 30, 2007	acromegaly, gastroenteropancreatic neuroendocrine tumors
degarelix	Dec 24, 2008	advanced prostate cancer
liraglutide	Jan 25, 2010	type 2 diabetes mellitus
tesamorelin †	Nov 10, 2010	see note below
icatibant	Aug 25, 2011	acute attacks of hereditary angioedema
carfilzomib	Jul 20, 2012	relapsed or refractory multiple myeloma
linaclotide	Aug 30, 2012	irritable bowel syndrome with constipation
pasireotide	Dec 14, 2012	Cushing's disease, acromegaly
teduglutide	Dec 21, 2012	short bowel syndrome with parenteral support
vasopressin	Apr 17, 2014	vasodilatory shock
dulaglutide †	Sep 18, 2014	type 2 diabetes mellitus
plecanatide	Jan 19, 2017	chronic idiopathic constipation
etelcalcetide	Feb 7, 2017	secondary hyperparathyroidism in dialysis patients
abaloparatide	Apr 28, 2017	osteoporosis at high fracture risk
semaglutide	Dec 5, 2017	see note below
bremelanotide	Jun 21, 2019	see note below
afamelanotide	Oct 8, 2019	phototoxicity in erythropoietic protoporphyria
setmelanotide	Nov 25, 2020	specified genetic obesity syndromes
pegcetacoplan	May 14, 2021	paroxysmal nocturnal hemoglobinuria
difelikefalin	Aug 23, 2021	pruritus in dialysis patients with chronic kidney disease
vosoritide	Nov 19, 2021	achondroplasia with open epiphyses
tirzepatide	May 13, 2022	see note below
terlipressin	Sep 14, 2022	hepatorenal syndrome with rapid decline in kidney function
motixafortide	Sep 8, 2023	stem cell mobilization in multiple myeloma
zilucoplan	Oct 17, 2023	generalized myasthenia gravis, AChR antibody positive
elamipretide	Sep 19, 2025	Barth syndrome, under accelerated approval

† Above the 40-residue line, and therefore licensed as biological products rather than approved as drugs. Insulin runs 51 residues, tesamorelin 44, and dulaglutide is two peptide analogs fused to an antibody fragment, which puts it far above the line. They appear here because every comparable list includes them, and omitting them without explanation would read as an oversight rather than as a definition.

Several cyclic and lipopeptide antibiotics and immunosuppressants also qualify as peptides under most definitions, including cyclosporine (approved 1983), daptomycin (2003) and vancomycin, which reached the market in the 1950s and predates the electronic record entirely. Whether they belong on a list like this is another question of definition rather than of fact.

A note on the omitted indications. Approved indications are omitted for molecules that are also supplied as research chemicals. An approved drug and a research chemical sharing an International Nonproprietary Name are different articles of commerce. The first is a defined formulation, manufactured under current Good Manufacturing Practice and reviewed under an approved application for a stated indication. The second is laboratory material, sold for research use only and reviewed by nobody.

The Counting Problem

No official number exists. The FDA publishes approvals; it does not publish a running total of approvals by molecular class, and where a peptide ends and a protein begins is a convention rather than a legal line.

The most cited figures come from peer-reviewed reviews and disagree with each other. A 2018 review counted over 60 approved peptide drugs across the United States and other major markets.^[4] A 2021 review counted more than 80 peptide drugs that had reached the market worldwide since insulin.^[3] A 2024 review put the figure at around 100 authorized by the FDA since 1921.^[13]

Some of that spread is real growth over six years. The rest is methodology: the reviews count different markets, apply different size boundaries, and make different decisions about analogs, conjugates and salt forms of the same molecule.

Those figures are also dated. Annual surveys of FDA approvals in the peptide and oligonucleotide class record continuing activity: of fifty novel drugs approved in 2024, four were peptides or oligonucleotides, and of forty-six novel drugs approved in 2025, four again fell in that class.^[5][6]

Underneath the disagreement sits the definitional problem described above. An author who applies the FDA's 40-residue line and an author who applies the chemists' 50-residue convention will publish different totals from identical data, and neither is making an error. Most published lists state no ceiling at all, which is what makes their totals impossible to check.

What Is Not Approved

The compounds most discussed in the research-peptide market are absent from Drugs@FDA entirely. A search of the database returns no approved application for BPC-157, TB-500 or thymosin beta-4, epitalon, MOTS-c, KPV, selank, semax, ipamorelin, CJC-1295, kisspeptin, ARA-290, delta sleep-inducing peptide, or melanotan II.

Retatrutide and cagrilintide are investigational. Both have been studied in registered clinical trials and neither holds an approved application, which is the status of a molecule that is under development rather than one that has been rejected.

Three further cases sit in a category people find counterintuitive.

Approved abroad, not in the United States. Semax and selank are registered as prescription drugs by the Russian Ministry of Health and have no US approval. Thymalfasin, also called thymosin alpha-1, is approved in dozens of countries and is not approved in the United States. A foreign registration carries no weight in US law.

Recommended by a committee, still unapproved. In July 2026 the Pharmacy Compounding Advisory Committee recommended six of seven peptides for the Section 503A bulk drug substances list, and the FDA's own review staff had proposed adding none of them.^[7] A recommendation is not a rule and a bulks-list placement is not an approval. We covered that meeting in detail in our analysis of the July 2026 PCAC vote.

Approved once, then withdrawn. This is sermorelin, and it deserves its own section.

Sermorelin: Approved Twice, Withdrawn in 2009

Sermorelin acetate held two approvals, not one. NDA 019863 was approved December 28, 1990, and NDA 020443 followed on September 26, 1997. Anyone claiming sermorelin was never an approved drug is wrong on the record, and anyone citing a single approval date has the record half right.

Both were withdrawn in the same notice, published May 19, 2009 and effective June 18, 2009, which withdrew 92 new drug applications and 49 abbreviated applications at once. The stated basis was administrative: the holders "notified the agency in writing that the drug products were no longer marketed and requested that the approval of the applications be withdrawn."^[8]

In March 2013 the FDA published a determination that the withdrawn sermorelin acetate injection products had not been withdrawn from sale for reasons of safety or effectiveness.^[9] That finding matters procedurally, because it permits abbreviated new drug applications to reference a discontinued product. It also settles a question that recurs in popular discussion: the withdrawal was commercial, and the agency said so in writing.

The practical result is a molecule with a real approval history and no currently effective approval. Sermorelin is still compounded, and the withdrawals changed which limb of the eligibility cascade can carry it: a substance stops being a component of an approved drug on the day the last approval lapses. Sermorelin acetate does not appear on the bulks list at 21 CFR 216.23.

Why "FDA Backs Peptides" Headlines Mislead

Coverage of advisory committee activity routinely uses verbs that imply agency action. A committee that "backed" six peptides or a panel that moved to "loosen rules" reads, to a person not tracking the procedure, as a rule that changed. No rule changed.

The sequence required before a bulks-list recommendation has legal effect is a notice of proposed rulemaking, a public comment period, a final rule, and an amendment to 21 CFR 216.23.^[11] The agency may decline at any point, and the sequence takes years rather than months.

The paper trail is public for anyone who wants to check the status directly. The meeting and its public docket were established by Federal Register document 2026-07361, published April 16, 2026 at 91 FR 20465, under docket FDA-2025-N-6895.^[14] The twelve substances that entered this process were removed from Category 2 of the bulks list effective April 22, 2026 because their original nominators withdrew, and the FDA's published position on what that removal accomplished is explicit: "Removal from Category 2 does not render these bulk drug substances eligible for compounding under section 503A."^[15]

Approval, meanwhile, is a different statutory process entirely, at 21 U.S.C. 355(a), and no advisory committee on compounding has authority over it. A substance can be recommended for the bulks list and remain an unapproved new drug indefinitely, because those two determinations answer different questions asked of different parties.

What Approval Says About Manufacturing

Approval carries an evidentiary record and a manufacturing standard. An approved product is made under current Good Manufacturing Practice, with identity, strength, purity and potency specifications tied to the application, and the FDA can inspect against them.

Material that carries no approval carries no such guarantee, and independent testing has repeatedly found the difference to be real. A 2024 analysis in the Journal of Medical Internet Research examined semaglutide products sold online without a prescription and documented quality and safety problems across multiple factors, including discrepancies between labeled and measured content.^[10]

Where no approval and no cGMP obligation apply, the only quality record that exists is whatever independent analysis has been performed and published for the specific batch. A sample certificate of analysis shows what such a report contains: identity confirmation by mass spectrometry, purity by high-performance liquid chromatography, and the analytical methods used to produce each figure.

Checking an Approval Claim Without Taking Anyone's Word

Every status claim above is checkable in a public database, and the procedure takes about a minute per molecule.

Drugs@FDA is searchable by active ingredient, and the openFDA interface exposes the same records programmatically.^[1][2] A molecule with an approval has at least one application containing an original submission marked approved, with a date attached. A molecule with no approval returns nothing, which is the result for BPC-157, TB-500, epitalon and the rest of the research-compound list.

Three details in that record repay attention. The application prefix separates a drug approval from a biologics license, which is where the 40-residue boundary shows up in practice. The submission marked original, rather than a later supplement, carries the first approval date, and supplements are what produce the inflated or shifted dates common in secondary sources. And the approved indication lives in the labeling record rather than in the application record, so a claim about what a drug is approved for should be traced to the label.

An absent record is weaker evidence than a present one. It establishes that no approval is recorded under the name searched, which is not quite the same as proving a molecule has never been approved anywhere under any name, as the sermorelin case illustrates. For a withdrawn approval, the Federal Register is the authoritative trail.

Regulatory Context, Date-Stamped

As of September 19, 2026, the approvals listed above stand as recorded in Drugs@FDA, and none of the research compounds named in the preceding section holds an approved application.

The Section 503A bulks-list rulemaking arising from the July 2026 committee recommendations has not been completed. Five further substances, LL-37, DiHexa, injectable GHK-Cu, PEG-MGF and melanotan II, are scheduled for committee review before the end of February 2027.^[7]

This article will be revised when the FDA acts on the rulemaking, when the February 2027 meeting occurs, or when a new peptide approval is recorded.

References

1. U.S. Food and Drug Administration. Drugs@FDA: FDA-Approved Drugs. Available at https://www.accessdata.fda.gov/scripts/cder/daf/. Accessed September 19, 2026.

2. U.S. Food and Drug Administration. openFDA Drug Product Labeling and Drugs@FDA APIs. Available at https://open.fda.gov/apis/drug/. Accessed September 19, 2026.

3. Muttenthaler M, King GF, Adams DJ, Alewood PF. Trends in peptide drug discovery. Nat Rev Drug Discov. 2021;20(4):309-325. PMID: 33536635.

4. Lau JL, Dunn MK. Therapeutic peptides: Historical perspectives, current development trends, and future directions. Bioorg Med Chem. 2018;26(10):2700-2707. PMID: 28720325.

5. Al Musaimi O, AlShaer D, de la Torre BG, Albericio F. 2024 FDA TIDES (Peptides and Oligonucleotides) Harvest. Pharmaceuticals (Basel). 2025;18(3). PMID: 40143070.

6. AlShaer D, Al Musaimi O, Albericio F, de la Torre BG. 2025 FDA TIDES (Peptides and Oligonucleotides) Harvest. Pharmaceuticals (Basel). 2026;19(2). PMID: 41754785.

7. U.S. Food and Drug Administration. July 23-24, 2026 Meeting of the Pharmacy Compounding Advisory Committee. Available at https://www.fda.gov/advisory-committees/advisory-committee-calendar/july-23-24-2026-meeting-pharmacy-compounding-advisory-committee-07232026. Accessed September 19, 2026.

8. Federal Register. Novartis Pharmaceuticals Corp. et al.; Withdrawal of Approval of 92 New Drug Applications and 49 Abbreviated New Drug Applications. Document E9-11628, May 19, 2009. Available at https://www.federalregister.gov/documents/2009/05/19/E9-11628/novartis-pharmaceuticals-corp-et-al-withdrawal-of-approval-of-92-new-drug-applications-and-49. Accessed September 19, 2026.

9. Federal Register. Determination That GEREF (Sermorelin Acetate) Injection, 0.5 Milligrams Base/Vial and 1.0 Milligrams Base/Vial, and GEREF (Sermorelin Acetate) Injection, 0.05 Milligrams Base/Amp, Were Not Withdrawn From Sale for Reasons of Safety or Effectiveness. Document 2013-04827, March 4, 2013. Available at https://www.federalregister.gov/documents/2013/03/04/2013-04827/determination-that-geref-sermorelin-acetate-injection-05-milligrams-basevial-and-10-milligrams. Accessed September 19, 2026.

10. Ashraf AR, Mackey TK, Vida RG, Kulcsár G, et al. Multifactor Quality and Safety Analysis of Semaglutide Products Sold by Online Sellers Without a Prescription: Market Surveillance, Content Analysis, and Product Purchase Evaluation Study. J Med Internet Res. 2024;26:e65440. PMID: 39509151.

11. Code of Federal Regulations. 21 CFR 216.23: Bulk drug substances that can be used to compound drug products in accordance with section 503A. Available at https://www.ecfr.gov/current/title-21/chapter-I/subchapter-C/part-216. Accessed September 19, 2026.

12. Food and Drug Administration. Definition of the Term "Biological Product." Final rule, 85 FR 10057, February 21, 2020, effective March 23, 2020. Document 2020-03505. Available at https://www.federalregister.gov/documents/2020/02/21/2020-03505/definition-of-the-term-biological-product. The definition is codified at 21 CFR 600.3. Accessed September 19, 2026.

13. Al Musaimi O. Exploring FDA-Approved Frontiers: Insights into Natural and Engineered Peptide Analogues in the GLP-1, GIP, GHRH, CCK, ACTH, and α-MSH Realms. Biomolecules. 2024;14(3). PMID: 38540684.

14. Federal Register. Pharmacy Compounding Advisory Committee; Notice of Meeting; Establishment of a Public Docket; Request for Comments. Document 2026-07361, 91 FR 20465, April 16, 2026. Docket FDA-2025-N-6895. Available at https://www.federalregister.gov/documents/2026/04/16/2026-07361/pharmacy-compounding-advisory-committee-notice-of-meeting-establishment-of-a-public-docket-request. Accessed September 19, 2026.

15. U.S. Food and Drug Administration. Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act, Category 2 list page. Quoted verbatim: "Removal from Category 2 does not render these bulk drug substances eligible for compounding under section 503A." Accessed September 19, 2026.