Educational Reference · Research-Use-Only
AOD-9604: Mechanism, Research, and Regulatory Status
A research-grade overview of AOD-9604 — what it is, how it works at the molecular level, what published studies have shown, and answers to the questions researchers ask most.
Last reviewed 2026-07-28
What is AOD-9604?
AOD-9604 is a synthetic hexadecapeptide corresponding to the C-terminal lipolytic domain of human growth hormone, residues 177-191, with an added N-terminal tyrosine and a disulfide bond between its two cysteines. It was developed on the hypothesis that the lipolytic and anti-lipogenic activity of growth hormone is separable from its somatogenic activity, which is mediated by GH receptor dimerization and downstream JAK2/STAT5 signaling leading to hepatic IGF-1 production. Consistent with that separation, AOD-9604 does not compete for the growth hormone receptor and does not induce cell proliferation or raise IGF-1 in the systems studied, and in rodents it did not reproduce the hyperglycemia and insulin resistance seen with full-length growth hormone.
In obese rodent models, chronic administration reduced body weight gain and increased whole-body fat oxidation, and was associated with increased adipose beta-3 adrenergic receptor expression. Importantly, the frequently repeated claim that AOD-9604 acts through beta-3 adrenergic receptor agonism is contradicted by the primary literature: Heffernan and colleagues tested the peptide in beta-3 adrenergic receptor knockout mice and concluded that the lipolytic actions of both growth hormone and AOD-9604 are not mediated directly through that receptor. The precise molecular target through which AOD-9604 exerts its rodent lipolytic effect has not been definitively established.
In anti-doping metabolism work the parent peptide is rapidly degraded, with a shorter fragment identified as a comparatively stable metabolite.
Research highlights
What published peer-reviewed research and preclinical studies have established about AOD-9604:
- 01In obese rodents, AOD-9604 reduced body weight gain and increased lipolytic activity in adipose tissue without impairing insulin sensitivity (Ng 2000).
- 02Chronic administration to obese and lean mice reduced body weight gain and increased fat oxidation and, unlike full-length growth hormone, did not cause hyperglycemia; the peptide did not compete for the GH receptor and did not induce cell proliferation (Heffernan 2001, Int J Obes).
- 03NEGATIVE MECHANISTIC FINDING: in beta-3 adrenergic receptor knockout mice the lipolytic effects of both growth hormone and AOD-9604 persisted, leading the authors to conclude these effects are not mediated directly through that receptor — contradicting the commonly repeated beta-3 agonist explanation (Heffernan 2001, Endocrinology).
- 04NEGATIVE CLINICAL FINDING: development for obesity was terminated in 2007 after the peptide failed to induce significant weight loss in a 24-week trial of 536 subjects; an earlier 12-week trial showed only a modest mean difference and the response was not dose-dependent, with the higher-dose arm performing worse than the lower (Valentino 2010).
- 05AOD-9604 is a target of anti-doping analysis, with a validated urine detection method published and the peptide shown not to interfere with the standard growth hormone isoform immunoassay (Cox 2015).
- 06No AOD-9604 study is registered on ClinicalTrials.gov, and the primary Phase II trial reports were never published in the peer-reviewed literature — trial results are known only through secondary review articles.
Published clinical and preclinical research
Phase IIb obesity trial (24 weeks)
Phase 2b · 2007FAILED to induce significant weight loss. Development of AOD-9604 for obesity was terminated in 2007 as a direct result. The primary trial report was never published in the peer-reviewed literature and the study is not registered on ClinicalTrials.gov; enrollment is reported as 536 by Valentino et al. while a sponsor-affiliated review describes a different figure, and that discrepancy is unresolved in the public record.
Frequently asked questions about AOD-9604
What is AOD-9604?+
AOD-9604 is a synthetic 16-amino-acid peptide corresponding to residues 177-191 of mature human growth hormone with an N-terminal tyrosine added and a disulfide bond between its two cysteine residues. It was developed as an investigational obesity candidate and is now used as a reference standard and research reagent, including in anti-doping analytical chemistry. It has never been approved for any indication.
How does AOD-9604 differ from HGH Fragment 176-191?+
They are related but not identical. hGH(176-191) begins with phenylalanine, whereas AOD-9604 is Tyr-hGH(177-191) and begins with tyrosine — the N-terminal residue differs. Because the two are frequently conflated in secondary sources, researchers should verify which sequence a given publication or reference standard actually used before comparing results.
What does the clinical literature actually show?+
The clinical program did not succeed. A 12-week trial showed a modest mean weight difference but without dose-dependence, and a subsequent 24-week trial in 536 subjects failed to produce significant weight loss, after which development for obesity was terminated in 2007. Reported tolerability was good and IGF-1 was not stimulated, but efficacy for the intended endpoint was not demonstrated, and none of the trial reports were published in the peer-reviewed literature.
Does AOD-9604 act as a beta-3 adrenergic agonist?+
No — this is a common misstatement. Heffernan and colleagues tested the peptide in beta-3 adrenergic receptor knockout mice and concluded that the lipolytic actions of both growth hormone and AOD-9604 are not mediated directly through that receptor. Adipose beta-3 receptor expression was observed to change with treatment, but that is a downstream association, not the mechanism. The definitive molecular target remains unestablished.
Does AOD-9604 raise IGF-1 or bind the GH receptor?+
The published work indicates it does not. AOD-9604 was reported not to compete for the growth hormone receptor and not to induce cell proliferation, and it did not stimulate IGF-1 production in the systems studied. This receptor-independence was the original design rationale for separating the lipolytic domain from the somatogenic activity of full-length growth hormone.
How should it be stored and handled?+
Store lyophilized material at -20C, desiccated and protected from light. This peptide contains an intramolecular disulfide bond, so conditions that promote reduction or disulfide scrambling — reducing agents, elevated temperature, pH extremes, prolonged storage in solution — should be avoided. Aliquot reconstituted stocks and confirm identity and purity analytically; published metabolism work shows the intact peptide degrades rapidly in biological matrices.
References & sources
Every citation below was resolved against its primary source before publication — each PMID against the PubMed record and each DOI through doi.org. Follow any link to read the paper at the publisher rather than taking our summary on trust.
- [1]Ng FM, Sun J, Sharma L, Libinaka R, Jiang WJ, Gianello R. Metabolic studies of a synthetic lipolytic domain (AOD9604) of human growth hormone. Hormone Research. 2000. PMID: 11146367 DOI: 10.1159/000053183
- [2]Heffernan MA, Thorburn AW, Fam B, et al.. Increase of fat oxidation and weight loss in obese mice caused by chronic treatment with human growth hormone or a modified C-terminal fragment. International Journal of Obesity and Related Metabolic Disorders. 2001. PMID: 11673763 DOI: 10.1038/sj.ijo.0801740
- [3]Heffernan M, Summers RJ, Thorburn A, et al.. 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. PMID: 11713213 DOI: 10.1210/endo.142.12.8522
- [4]Valentino MA, Lin JE, Waldman SA. Central and peripheral molecular targets for antiobesity pharmacotherapy. Clinical Pharmacology and Therapeutics. 2010. PMID: 20445536 DOI: 10.1038/clpt.2010.57
- [5]Cox HD, Smeal SJ, Hughes CM, Cox JE, Eichner D. Detection and in vitro metabolism of AOD9604. Drug Testing and Analysis. 2015. PMID: 25208511 DOI: 10.1002/dta.1715
Where this data comes from
- —Citations & trial data: PubMed (NCBI, U.S. National Library of Medicine), Crossref and ClinicalTrials.gov.
- —Chemical identity: PubChem and UniProt. Where sources conflicted, the disputed value is omitted rather than guessed.
- —Regulatory status: U.S. FDA publications and, where applicable, the WADA Prohibited List. Compounding status changes frequently — verify against FDA directly before relying on it.
- —Purity, form and storage are handling and supplier conventions, not literature-derived values. Confirm against the lot-specific certificate of analysis.
Content last reviewed 2026-07-28. Compiled by Veridian Research from the primary literature. This page is an educational reference for laboratory researchers — it is not medical advice, and it describes no human use.
Regulatory status
AOD-9604 is not approved by the FDA, EMA, TGA, or any other regulatory authority for any indication. Clinical development for obesity was terminated by the sponsor in 2007 following failure to meet the weight-loss endpoint in a 24-week Phase IIb trial. The peptide is a substance of interest in sport anti-doping analysis and validated detection methods have been published. Its status under the FDA 503A bulk drug substances compounding framework has been subject to repeated review and change; any statement about current compounding eligibility must be verified against FDA's currently published list rather than reproduced from secondary sources. Supplied strictly as a research chemical for in vitro and non-clinical laboratory investigation — not for human consumption, therapeutic use, veterinary use, or administration to any living subject.
Research-Use-Only Material
Specifications and certificate of analysis
AOD-9604 is stocked as a research reagent. Analytical documentation — identity, purity and the lot-specific certificate of analysis — is published on the product record.
View specifications & COA →