AOD 9604: Research Overview, Mechanisms, and Current Evidence
AOD 9604 is a synthetic peptide based on the C-terminal region (residues 176 to 191) of human growth hormone. It was developed to capture the fat-metabolizing activity of growth hormone without its growth-promoting effects, and it was studied as a potential anti-obesity agent. It reached clinical development but did not establish weight-loss efficacy in human trials and is not an approved drug. The information below summarizes published research for educational and research purposes only. It is not medical advice and is not guidance for use in humans.
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How It Works (Preclinical Mechanisms)
In preclinical models, AOD 9604 and related growth hormone fragments have been reported to influence fat metabolism while lacking the growth-promoting and glucose effects of full growth hormone.
- Based on the lipolytic C-terminal region of human growth hormone, studied for breaking down stored fat.
- Reported to increase lipolysis (fat breakdown) and reduce lipogenesis (fat formation) in adipose tissue models.
- Studied as lacking the growth-promoting and insulin-related effects associated with intact growth hormone.
- Reported to increase energy expenditure and fat oxidation in animal models of obesity.
Areas of Research Interest
Published studies have examined AOD 9604 and related growth hormone fragments primarily in the context of obesity and fat metabolism.
Obesity and weight
Studied as a candidate anti-obesity agent that reached early clinical development.
Adipose tissue metabolism
Investigated in animal and human adipose tissue for effects on fat breakdown and formation.
Energy expenditure
Examined for effects on energy use and fat oxidation in rodent models of obesity.
Growth hormone pharmacology
Studied to separate the fat-metabolizing actions of growth hormone from its growth-promoting effects.
Reported Study Parameters
For laboratory research use only. The table below reports the models and routes used in published studies, with sources. It describes what researchers administered in these models and is not a protocol, recommendation, or guidance for use in humans or animals. Where a primary study did not report a numeric per-kilogram dose in the indexed record, that is noted rather than estimated.
| Research Model | Dose and Route Reported | Source |
|---|---|---|
| Obesity model (ob/ob mice), related hGH C-terminal fragment | Oral administration for 30 days; reduced weight gain and increased lipolysis; specific dose reported in the source | Heffernan 2000·DOI |
| Human adipose tissue (in vitro) | Increased lipolytic activity and decreased lipogenic activity in isolated human adipose tissue; concentration reported in the source | Heffernan 2000·DOI |
| Human research | Reached Phase II clinical development as an anti-obesity agent; reviews indicate it did not establish significant weight-loss efficacy and it is not an approved drug | Wilding 2004·Halford 2006 |
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Latest Research (2000 to 2026)
Peer-reviewed literature indexed on PubMed includes foundational fat-metabolism studies, reviews of its clinical development, and recent overviews of unapproved peptides.
Peptides in sports medicine (review)
A 2026 narrative review of approved and unapproved peptides included AOD-9604 among compounds with favorable metabolic outcomes in animal models but scarce rigorous human safety data, noting the gap between marketing claims and evidence. PubMed·DOI
Obesity drugs in development (review)
A 2006 review of anti-obesity drugs in clinical development described AOD-9604 as a human growth hormone fragment that increases adipose tissue breakdown, placing it among peripherally acting candidate therapies of that era. PubMed
Development status review
A 2004 profile reported that AOD-9604 was being developed for obesity, with Phase IIa trials underway as of early 2002, reflecting its progression into human testing. PubMed
Fat metabolism (foundational study)
A 2000 study reported that an orally administered synthetic growth hormone fragment reduced weight gain in obese mice and increased lipolytic activity while decreasing lipogenic activity in rodent and human adipose tissue. PubMed·DOI
Research Questions
What is AOD 9604?
AOD 9604 is a synthetic fragment of the C-terminal region of human growth hormone, studied for fat-metabolizing activity without the growth-promoting effects of the full hormone.
What is the current state of human evidence?
AOD 9604 reached Phase II clinical development as an anti-obesity candidate but did not establish significant weight-loss efficacy in human trials, and it is not an approved drug.
What does the available safety literature suggest?
Animal and early human studies did not flag major safety problems, but rigorous, large-scale human safety and efficacy data are lacking, so it should be treated as investigational.
Referenced Citations
Literature indexed on PubMed.
- Mendias, C.L., & Awan, T.M. (2026). Safety and efficacy of approved and unapproved peptide therapies for musculoskeletal injuries and athletic performance. Sports Med. PubMed·DOI
- Halford, J.C.G. (2006). Obesity drugs in clinical development. Curr. Opin. Investig. Drugs, 7(4), 312-318. PubMed
- Wilding, J. (2004). AOD-9604 Metabolic. Curr. Opin. Investig. Drugs, 5(4), 436-440. PubMed
- Heffernan, M.A., et al. (2000). Effects of oral administration of a synthetic fragment of human growth hormone on lipid metabolism. Am. J. Physiol. Endocrinol. Metab., 279(3), E501-E507. PubMed·DOI
PeptideInfo.org provides information strictly for educational and research purposes. All referenced products are intended for laboratory and research use only and are not approved for human consumption, medical use, or self-administration. Nothing on this page constitutes medical advice. Research summaries reference literature indexed on PubMed.