AOD-9604

01 · What it is

A 2004 industry review reported that phase IIa trials of AOD-9604 for obesity were underway as of February 2002 ¹⁰. Twenty-two years later, this guide located no published human trial of the compound at all.

That gap is the finding. Not that the trials failed — this guide does not know what they found. That a compound entered phase II in 2002, is still sold today, and has no human efficacy publication in the peer-reviewed record that this search could locate.

What it is, precisely. The anti-doping literature gives the structure without ambiguity: AOD9604 is a peptide consisting of the C-terminal fragment of human growth hormone from amino acids 177 to 191, with an additional tyrosine residue at the N-terminus ¹³.

That sentence should be read against the label on the product most often sold alongside it. The compound with the research programme is 177–191 plus a tyrosine. The compound named on the market is “HGH Fragment 176-191.” Those are different descriptions, and this project treats a residue-number discrepancy as a fact about identity, not a typo.

The animal evidence is real and it is twenty-five years old. Three studies between 2000 and 2001 reported increased lipolytic activity in adipose tissue of obese Zucker rats ⁷, increased in vivo fat oxidation and plasma glycerol in obese mice ⁸, and effects on lipid metabolism in obese mice and beta-3 adrenergic receptor knockout mice ⁹.

The most useful of those studies asked whether the mechanism is what it appears to be. The 2001 International Journal of Obesity paper used in vitro assays to test whether AOD9604’s effects are mediated through the human growth hormone receptor, and whether the peptide can drive cell proliferation through that receptor ⁸. Asking the proliferation question about a growth-hormone fragment is the right question to ask, and it is asked far too rarely in this project’s subject matter.

02 · Evidence at a glance

Evidence grade

Preclinical — no published human trial located

Structure, per the anti-doping literature

hGH C-terminal fragment amino acids 177–191, plus an N-terminal tyrosine ¹³

Development status, 2004 report

Phase IIa trials underway as of February 2002 ¹⁰

Published human trial

None located — see limitations

Animal fat-loss data

Obese Zucker rats ⁷; obese mice ⁸; obese and β3-AR knockout mice ⁹

Mechanism question asked

Whether effects are hGH-receptor-mediated, and whether the peptide drives cell proliferation through that receptor ⁸

Other animal work

Intra-articular injection in a rabbit osteoarthritis model, with and without hyaluronic acid ¹⁴

Anti-doping detection

Detection method and in vitro metabolism published; a stable metabolite identified ¹³; covered in sports drug-testing reviews ¹⁵

Contemporary reviews

Listed among unapproved peptides marketed direct to patients ²⁰; among peptides in orthopaedic use ¹⁸; among GH-IGF1-axis agents used in self-administration ¹⁹

A mischaracterisation in the recent literature

One 2026 review groups AOD-9604 with growth hormone secretagogues ¹⁸ — which, on the structural evidence ¹³, it is not

Regulatory status

No marketing authorisation located

03 · Mechanism of action

A fragment of a hormone, not the hormone

AOD-9604 is the C-terminal region of human growth hormone with an added tyrosine ¹³. The design premise, evident from the 2000–2001 studies, is that the lipolytic activity of growth hormone can be separated from its other actions by using only the domain responsible for it — a synthetic analogue of the lipolytic domain ⁷.

The premise is elegant and it is the same premise this project has examined for several other fragment compounds: that a protein’s functions are modular and separable. Sometimes that is true. Whether it is true here was the question the phase II programme presumably existed to answer, and this guide does not have the answer.

The receptor question, and the proliferation question

The 2001 study explicitly used in vitro assays to determine whether AOD9604’s effects are mediated through the hGH receptor and whether the peptide is capable of driving cell proliferation via that receptor ⁸.

Growth hormone signalling promotes cell proliferation. Any fragment marketed on the basis that it keeps the metabolic effect while shedding the rest has to answer whether it also sheds the proliferative one. The study asked; this guide has read the abstract’s framing and not its numeric answer, and does not report a conclusion it has not read.

What the fragment literature shows about fragments generally

The broader literature on growth hormone fragments is a fifty-year collection of different fragments with different activities. A 1997 study reported that human growth hormone fragment 44–91 produces insulin resistance and hyperinsulinaemia in the rat, though less potently than intact 22 kDa hGH ⁶. A 1988 study reported that fragment 32–38 increases glucose uptake in the conscious dog ⁵. A 1980 study found somatomedin-like bioactivity in a fragment designated A-II ³. A 2023 paper characterises a 14-kilodalton fragment as an inhibitor of angiogenesis and tumour metastasis ¹⁷.

This is the most important context in the guide and it generalises well beyond this compound. One fragment of growth hormone raises insulin resistance, another improves glucose uptake, another inhibits angiogenesis, another has somatomedin-like activity. Which residues are present is not a detail. It is the whole of what the molecule does — which is exactly why a discrepancy between 177–191 and 176–191 on a label is worth stating rather than smoothing over.

04 · Key research findings

The compound

Obese Zucker rats, 2000. A synthetic analogue of the lipolytic domain of human growth hormone was studied for metabolic actions. Adipose tissue of treated animals showed increased lipolytic activity ⁷.

Obese mice, 2001. Chronic treatment with human growth hormone or with a modified C-terminal fragment produced increased fat oxidation and weight loss, associated with increased in vivo fat oxidation and increased plasma glycerol. In vitro assays addressed hGH-receptor mediation and proliferative capacity ⁸.

Obese and knockout mice, 2001. Both human growth hormone and the lipolytic fragment induced weight loss and increased lipolytic sensitivity after long-term treatment in mice; in an acute experiment, AOD9604 was capable of increasing a measured parameter, in a study design that included beta-3 adrenergic receptor knockout mice ⁹.

The knockout arm is the methodologically serious part. Including animals lacking the receptor most associated with adipose lipolysis is a way of testing whether the effect runs through that pathway, rather than assuming it. This is better experimental design than most preclinical work covered in this project.

Rabbit osteoarthritis, 2015. Weekly intra-articular injections in a collagenase-induced model, in four groups: saline, hyaluronic acid 6 mg, AOD9604 0.25 mg, and AOD9604 0.25 mg with hyaluronic acid 6 mg, administered for 4–7 weeks after the first collagenase injection, with lameness period among the measures ¹⁴.

An unexpected indication and a small animal study. Its presence is a reminder that this compound’s published research has moved away from obesity rather than towards a human obesity result.

Detection and metabolism, 2015. A method for detecting AOD9604 and characterising its in vitro metabolism, identifying a stable metabolite that may allow an increased detection window ¹³. The compound also appears in a broad review of sports drug testing by mass spectrometry ¹⁵.

The anti-doping literature is where this compound’s most precise published chemistry lives. That is a recurring pattern across this project: the people who most need to know exactly what a molecule is are the ones testing for it.

Development history

2004. An industry-development review states that the sponsor was developing AOD-9604 for the potential treatment of obesity, and that phase IIa trials were underway by February 2002 ¹⁰.

2006. A review of obesity drugs in clinical development surveys the field of that period ¹¹.

2012. A review of medical management of obesity lists AOD9604 among recent patents alongside oleoyl-estrone, TRK-beta antagonists and melanin-concentrating hormone ¹².

The synthesis for this section: the compound’s trajectory in the literature runs from active clinical development in the early 2000s, through patent-and-pipeline reviews, to its present position as a compound discussed mainly in the context of unregulated sale. At no point in that sequence did this search find a published human efficacy result.

The present-day literature

Orthopaedic review, 2026. A review of therapeutic peptides in orthopaedics groups AOD-9604 with growth hormone secretagogues such as ipamorelin, CJC-1295, tesamorelin and sermorelin ¹⁸.

That grouping is wrong on the structural evidence. A secretagogue stimulates release of endogenous growth hormone; AOD-9604 is a fragment of the hormone itself ¹³. This guide flags the discrepancy rather than repeating it, and notes that a peer-reviewed review misclassifying a compound is a reason to read primary sources rather than reviews.

Sports medicine review, 2026. A review of the pharmacological mechanisms, safety profiles and regulatory status of prominent approved and unapproved peptides marketed direct to patients, naming AOD-9604 (anti-obesity drug 9604) alongside BPC-157 and CJC-1295 ²⁰.

GH-IGF1 axis review, 2026. A review of performance-enhancing peptides modulating the GH-IGF1 axis, framed explicitly around the gap between clinical evidence and patient self-administration, and covering agents encountered in clinical practice and in online self-administration protocols ¹⁹.

Both 2026 reviews approach the compound as a market phenomenon requiring clinical guidance rather than as a therapeutic candidate with evidence. That is an accurate reflection of where it sits.

05 · Evidence overview

06 · Safety profile

There is no human safety data for this compound in the literature located here. No published human trial was found, so no adverse-event profile, no tolerability data and no dose-ranging safety information exists in what this guide read.

Animal data. Chronic treatment studies in obese rodents ^7,8,9 and a small rabbit study ¹⁴ reported the outcomes described above. No dedicated toxicology study was retrieved.

The mechanistic safety question that was asked and is not answered here. The 2001 study set out to determine whether the peptide is capable of driving cell proliferation through the growth hormone receptor ⁸. This guide has read that the question was posed and has not read the answer. For a fragment of a growth-promoting hormone, that is the central safety question, and leaving it open is the honest position rather than a comfortable one.

What the fragment literature implies. Other fragments of the same hormone have opposite metabolic effects — one producing insulin resistance and hyperinsulinaemia ⁶, another increasing glucose uptake ⁵. Nothing about being a growth hormone fragment predicts a benign metabolic profile.

What is genuinely unknown. Everything about administration to people, outside whatever the unpublished phase II programme found. Identity, purity and concentration of any product sold under this name are also unexamined in the located literature.

07 · US regulatory status

Current as of 7 September 2026. This guide located no marketing authorisation for AOD-9604 in any jurisdiction. A 2026 review describes it among unapproved peptides marketed direct to patients ²⁰, and a second frames the field around the gap between clinical evidence and self-administration ¹⁹.

This guide has not consulted FDA, EMA, TGA or any other regulatory record, and makes no statement about any agency’s determinations regarding this compound.

An unapproved drug cannot lawfully be supplied for human use in the United States outside an authorised clinical trial or a formal expanded-access pathway.

A validated detection method and characterised stable metabolite exist for anti-doping purposes ¹³, and the compound appears in mass-spectrometry testing reviews ¹⁵. Competitors should consult the current Prohibited List directly rather than rely on secondary summaries, including this one.

08 · Limitations of the evidence

1. No published human trial was located, despite a 2004 report that phase IIa trials had been underway since February 2002 ¹⁰. Whether results were published elsewhere, published under a different designation, or never published, this guide does not know. It is the single most important open question about this compound.
2. The compound’s residue numbering in the literature is 177–191 plus an added tyrosine ¹³, which does not match the designation under which the closely associated product is sold. This guide treats that as a fact requiring explanation rather than an equivalence to be assumed.
3. The primary research is a quarter of a century old. The obesity studies date from 2000 and 2001 ^7,8,9; the most recent primary work on the compound located here is from 2015 ^13,14.
4. The proliferation result is not reported here ⁸. The question was asked in vitro; this guide read the framing and not the finding.
5. All efficacy data are rodent data ^7,8,9, in models of diet-induced or genetic obesity.
6. A 2026 peer-reviewed review misclassifies the compound as a growth hormone secretagogue ¹⁸. Where recent reviews contradict primary structural sources, this guide follows the primary source and says so.
7. No dedicated toxicology study was retrieved.
8. No independent analysis of any marketed product was located.
9. The osteoarthritis study is small, in rabbits, by a single group ¹⁴, and is not corroborated.
10. The wider fragment literature is heterogeneous by construction ^{1,2,3,4,5,6,16,17}. It is cited here to establish that fragments differ, not to characterise this compound.
11. Twenty of 43 records were examined, and this guide has read abstracts, not full texts.

09 · Legal and regulatory appendix

This appendix applies to every compound in this family and is reproduced in each guide.

Approval status. This guide located no marketing authorisation for AOD-9604. Supplying or administering an unapproved drug for human use is unlawful in the United States and in most other jurisdictions outside an authorised trial or expanded-access pathway. This guide does not describe how to obtain the compound and takes no position on any supplier.

Products sold under this name. Material sold as AOD-9604 has no established relationship to the material used in the studies cited here — and, given the residue-numbering discrepancy described above, may not have the same structure. This guide located no published analysis of the identity, purity, concentration, sterility or contamination status of any such product.

Research-use labelling. Material labelled for laboratory research use is not manufactured, tested, or released to the standards applied to medicines intended for people, and such labelling does not make administration lawful or safe.

What this guide is. A description of the published peer-reviewed literature, written for readers who want to understand the state of the evidence. It is not medical advice, not a recommendation, not an endorsement, and not a substitute for a clinician who can assess an individual situation.

Editorial position. Arkham Labs publishes independently and earns through disclosed referral links. That commercial relationship is disclosed on every page carrying such a link and on the editorial standards page. It does not alter what the evidence says, and this guide reports that a compound in active sale has no located human trial publication in twenty-four years.

10 · References

1. Yamasaki N, Shimanaka J, Sonenberg M. Studies on the common active site of growth hormone. Revision of the amino acid sequence of an active fragment of bovine growth hormone. J Biol Chem. 1975 Apr 10;250(7):2510–2514.

   PMID 1123321 ↗

2. Benveniste R, Warshaw ML, Frohman LA, Reagan CR, Kostyo JL. Possible evidence for the existence of a growth hormone fragment in porcine pituitary. Biochim Biophys Acta. 1977 Mar 29;497(1):307–316.

   PMID 849485 ↗

3. Hubbard JR, Liberti JP. Somatomedin-like bioactivities of a growth hormone fragment on embryonic chick cartilage and cultured human fibroblasts. Biochim Biophys Acta. 1980 Jan 17;627(2):207–214.

   PMID 7350924 ↗

4. Mercola KE, Cline MJ, Golde DW. Growth hormone stimulation of normal and leukemic human T-lymphocyte proliferation in vitro. Blood. 1981 Aug;58(2):337–340.

   PMID 6972789 ↗

5. Stevenson RW, Stebbing N, Jones T, Carr K, Jones PM, Hii C, Cherrington AD. The synthetic human growth hormone fragment (32-38) increases glucose uptake in the conscious dog. Acta Endocrinol (Copenh). 1988 Apr;117(4):457–462.

   PMID 3291525 ↗

6. Hettiarachchi M, Watkinson A, Leung KC, Sinha YN, Ho KK, Kraegen EW. Human growth hormone fragment (hGH44-91) produces insulin resistance and hyperinsulinemia but is less potent than 22 kDa hGH in the rat. Endocrine. 1997 Feb;6(1):47–52.

   PMID 9225115 ↗

7. Ng FM, Sun J, Sharma L, Libinaka R, Jiang WJ, Gianello R. Metabolic studies of a synthetic lipolytic domain (AOD9604) of human growth hormone. Horm Res. 2000;53(6):274–278.

   PMID 11146367 ↗

8. Heffernan MA, Thorburn AW, Fam B, Summers R, Conway-Campbell B, Waters MJ, Ng FM. Increase of fat oxidation and weight loss in obese mice caused by chronic treatment with human growth hormone or a modified C-terminal fragment. Int J Obes Relat Metab Disord. 2001 Oct;25(10):1442–1449.

   PMID 11673763 ↗

9. Heffernan M, Summers RJ, Thorburn A, Ogru E, Gianello R, Jiang WJ, Ng FM. The effects of human GH and its lipolytic fragment (AOD9604) on lipid metabolism following chronic treatment in obese mice and beta(3)-AR knock-out mice. Endocrinology. 2001 Dec;142(12):5182–5189.

   PMID 11713213 ↗

10. Wilding J. AOD-9604 Metabolic. Curr Opin Investig Drugs. 2004 Apr;5(4):436–440. Review.

    PMID 15134286 ↗

11. Halford JC. Obesity drugs in clinical development. Curr Opin Investig Drugs. 2006 Apr;7(4):312–318. Review.

    PMID 16625817 ↗

12. Khan A, Raza S, Khan Y, Aksoy T, Khan M, Weinberger Y, Goldman J. Current updates in the medical management of obesity. Recent Pat Endocr Metab Immune Drug Discov. 2012 May;6(2):117–128. Review.

    PMID 22435392 ↗

13. Cox HD, Smeal SJ, Hughes CM, Cox JE, Eichner D. Detection and in vitro metabolism of AOD9604. Drug Test Anal. 2015 Jan;7(1):31–38.

    PMID 25208511 ↗

14. Kwon DR, Park GY. Effect of intra-articular injection of AOD9604 with or without hyaluronic acid in rabbit osteoarthritis model. Ann Clin Lab Sci. 2015 Summer;45(4):426–432.

    PMID 26275694 ↗

15. Schänzer W, Thevis M. Human sports drug testing by mass spectrometry. Mass Spectrom Rev. 2017 Jan;36(1):16–46. Review.

    PMID 26213263 ↗

16. Habibullah MM, Mohan S, Syed NK, Makeen HA, Jamal QMS, Alothaid H, Bantun F, Alhazmi A, Hakamy A, Kaabi YA, Samlan G, Lohani M, Thangavel N, Al-Kasim MA. Human growth hormone fragment 176-191 peptide enhances the toxicity of doxorubicin-loaded chitosan nanoparticles against MCF-7 breast cancer cells. Drug Des Devel Ther. 2022 Jun 27;16:1963–1974.

    PMID 35783198 ↗

17. Shaker BT, Ismail AA, Salih R, Hadj Kacem H, Rahmani M, Struman I, Bajou K. The 14-kilodalton human growth hormone fragment a potent inhibitor of angiogenesis and tumor metastasis. Int J Mol Sci. 2023 May 17;24(10):8877.

    PMID 37240223 ↗

18. Rahman OF, Lee SJ, Seeds WA. Therapeutic peptides in orthopaedics: applications, challenges, and future directions. J Am Acad Orthop Surg Glob Res Rev. 2026 Jan 2;10(1):e25.00236. Review.

    PMID 41490200 ↗

19. Dominikowski A, Rękoś Z, Olejarz M, Szczepanek-Parulska E, Domin R, Ruchała M. The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration. Front Endocrinol (Lausanne). 2026 Jun 18;17:1822475. Review.

    PMID 42395176 ↗

20. Mendias CL, Awan TM. Safety and efficacy of approved and unapproved peptide therapies for musculoskeletal injuries and athletic performance. Sports Med. 2026 Aug;56(8):1921–1935. Review.

    PMID 41966639 ↗