AOD-9604

Of growth hormone, AOD-9604 keeps only a small excerpt: amino acids 177 to 191 from the C-terminal end, described in the analytical literature with an extra tyrosine at the N-terminus. In research models this excerpt carries the hormone's lipolytic property but not its action on growth or insulin sensitivity.

What the preclinical work records:

• Hormone-sensitive lipase: the fragment stimulates its activity in adipocytes, releasing more free fatty acids from adipose tissue.
• Lipogenesis: in animal models, new fat formation came out lower.
• Beta-3 adrenoceptor: the fragment raised its expression in obese mice, and in knockout animals lacking the receptor the weight effect was absent; the mechanism is not settled conclusively.
• Receptor binding: AOD-9604 does not bind the growth hormone receptor, and neither hyperglycemia nor cell proliferation appeared in the mouse studies.

The clinical history: the peptide was once tested in humans in obesity models, but the phase 2 results came out mixed, so no phase 3 followed. In the research community it has nonetheless remained a tool for the fragment mechanism. The half-life is short, which is why preclinical protocols worked with daily subcutaneous dosing. For context: the substance is on the WADA prohibited list, and a urine detection method has been validated. Below you find the three animal studies, the analytical paper and a recent review.

Studies rate AOD-9604 as well tolerated. Since only the C-terminal fragment is present, the growth- and insulin-related actions of the full hormone are absent, which keeps the profile comparatively narrow.

• Injection site: mild redness, pressure or brief irritation is the most common observation, especially with daily subcutaneous dosing.
• Circulation: isolated reports of warmth, slight dizziness or fatigue shortly after administration.
• Efficacy: the mixed phase 2 data concern effect rather than safety; they are the reason no phase 3 took place.
• Evidence base: robust long-term human data are lacking, the assessment rests on animal models and short-term experience, and a 2026 review calls human safety data scarce.

This summary is no substitute for medical advice.

• Metabolic studies of a synthetic lipolytic domain (AOD9604) of human growth hormone - obese Zucker rats, 19 days of daily oral dosing: weight gain more than halved, higher lipolytic activity, insulin sensitivity unchanged.
• Fat oxidation and weight loss in obese mice with hGH or a modified C-terminal fragment - 14-day mouse study: less weight gain, more fat oxidation, no binding to the hGH receptor.
• Human GH and its lipolytic fragment (AOD9604) in obese and beta(3)-AR knock-out mice - the beta-3 adrenoceptor paper, including the knockout animals without a weight effect.
• Detection and in vitro metabolism of AOD9604 - analytics: structure with N-terminal tyrosine, urine detection, stable serum metabolite, WADA status.
• Peptide Therapies for Musculoskeletal Injuries and Athletic Performance: Safety and Efficacy - a 2026 narrative review covering approved and unapproved peptides, AOD-9604 included.