AOD-9604 is a short synthetic peptide copied from one end of human growth hormone (hGH). It corresponds to residues 176-191 of the hormone, with a tyrosine added at the front, giving a 16-amino-acid chain that is cyclized by a disulfide bond between two cysteines. It is also written AOD9604 or AOD 9604, and was sometimes called an "Anti-Obesity Drug," which is where the AOD comes from.
It was developed in Australia by Metabolic Pharmaceuticals in the 1990s and 2000s. The idea was to isolate the part of growth hormone that breaks down fat (its lipolytic domain) and leave behind the parts that drive growth and disturb blood sugar.
What the research actually showed
The early work was in animals. In a study published in Hormone Research, obese Zucker rats given oral AOD9604 had their body-weight gain cut by more than half over 19 days, with increased lipolytic activity in fat tissue and, importantly, no measured harm to insulin sensitivity (Ng et al., 2000). A separate set of experiments in obese mice reported that, unlike intact growth hormone, the fragment did not compete for the hGH receptor, did not raise IGF-1, and did not cause hyperglycemia, while still reducing weight gain and stimulating fat oxidation (Heffernan et al., *Endocrinology*, 2001). The proposed mechanism tied to the β3-adrenergic system: both hGH and AOD9604 raised β3-adrenergic receptor expression in fat, though the lipolysis was not acting directly through that receptor.
Then it went to people. AOD-9604 is unusual among "research peptides" in that it was put through real human trials. Across roughly six controlled clinical studies involving more than 900 participants, it was generally well tolerated. The efficacy is the problem. A 12-week trial showed only a modest edge over placebo (on the order of a couple of kilograms), and the larger and longer studies did not produce a fat-loss effect strong enough to justify the program. Development as an obesity drug was halted in 2007 for poor efficacy.
So the honest summary: the safety record from those trials is reasonably documented, but it never cleared the bar as a weight-loss medicine.
Regulatory and anti-doping status
AOD-9604 is not an approved drug anywhere. After the pharmaceutical program ended, its safety dossier was repurposed toward food and supplement use. A 2014 review reported that the compound received "generally recognized as safe" (GRAS) status for intended use in foods, drinks and dietary supplements, citing non-clinical toxicology and genotoxicity data (Moré & Kenley, *Journal of Endocrinology and Metabolism*, 2014). GRAS for a food ingredient is a different thing from FDA approval as a drug, and it does not establish that the peptide treats any condition.
For athletes, it is banned. AOD-9604 is treated as a growth-hormone fragment under section S2 of the WADA Prohibited List and is prohibited at all times, in and out of competition.
Material sold to consumers as AOD-9604 is typically labeled research-use-only and is not approved for human consumption. None of the above is medical or dosing advice.
The quality angle for buyers
Because there is no approved pharmaceutical version, anything on the market is made and sold outside that oversight. That puts the burden on independent verification. The questions worth asking about any vial are basic identity and purity ones: does a third-party certificate of analysis (COA) confirm the peptide is actually the 176-191 fragment and not a different sequence, and what purity does mass-spectrometry and HPLC testing report? peptideone aggregates third-party COAs and vendor ratings so those numbers can be compared across sellers rather than taken on a label's word.