AOD-9604: the growth hormone fragment and its research record

Abstract ball-and-stick molecular chain in blue tones

Prepared by: Research Desk. Sources are linked for verification.

Published 20 October 2026

At a glance

Type: synthetic peptide of 16 amino acids, based on the C-terminal region (residues 177 to 191) of human growth hormone (hGH)
Origin: developed from work at Monash University in Melbourne, Australia, in the 1990s
Research stage: mostly rodent studies from the originating group, plus analytical work by doping-control laboratories
Regulatory status: not an approved medicine; named on the World Anti-Doping Agency (WADA) Prohibited List

What AOD-9604 is

Human growth hormone is a protein of 191 amino acids. Its last fifteen residues, numbered 177 to 191, have the sequence Leu-Arg-Ile-Val-Gln-Cys-Arg-Val-Ser-Glu-Gly-Ser-Cys-Gly-Phe. AOD-9604 is a synthetic version of this C-terminal fragment with one extra tyrosine residue added at the N-terminus, as described by Cox et al. (2015). The result is a 16-residue peptide. The letters "AOD" are usually expanded as "anti-obesity drug", a reference to the purpose for which it was first developed.

AOD-9604 is a fragment, not a growth hormone analogue in the usual sense. In laboratory work it was reported not to bind the growth hormone receptor, which sets it apart from full-length hGH.

Research history

The idea behind AOD-9604 came from older work on how growth hormone affects metabolism. From the late 1970s, researchers at Monash University made short synthetic pieces of hGH and tested which parts of the molecule carried its effects on glucose and fat metabolism. Frank Ng's group reported in 1993 that the synthetic 177-191 fragment showed antilipogenic activity (reduced fat synthesis) in rat fat tissue similar to that of intact hGH (Wu and Ng, 1993).

The modified fragment, AOD-9604, followed. The company Metabolic Pharmaceuticals took it into clinical development, and a 2004 drug profile by Wilding recorded that phase IIa trials were under way by February 2002. We found no full peer-reviewed report of the company's later trials in PubMed, and the compound never reached approval.

Mechanisms studied in preclinical work

The main rodent studies come from the Monash group and were published between 2000 and 2001.

Obese rats. Ng et al. (2000) studied obese Zucker rats over 19 days. Body weight gain in the AOD-9604 group was less than half that of controls, and fat tissue showed higher lipolytic activity (fat breakdown). Unlike chronic exposure to intact hGH, AOD-9604 showed no adverse effect on insulin sensitivity in euglycemic clamp tests, a standard laboratory measure of insulin sensitivity.
Obese mice and the hGH receptor. In a 14-day study in obese (ob/ob) and lean mice, Heffernan et al. (2001) reported lower body weight gain, higher fat oxidation and higher plasma glycerol, a marker of lipolysis. Unlike hGH, AOD-9604 did not raise blood glucose or lower insulin secretion. In cell assays it did not compete for the hGH receptor and did not drive cell proliferation.
Beta-3 adrenergic receptors. A companion paper by Heffernan et al. (2001) in Endocrinology found that both hGH and AOD-9604 raised beta-3 adrenergic receptor RNA in the fat of obese mice. In mice lacking that receptor, long-term exposure did not change body weight or lipolysis, yet a short-term experiment still showed higher energy expenditure and fat oxidation. The authors concluded that the receptor is not the direct mediator of the fragment's lipolytic action.
Cartilage model. In a separate line of work, Kwon and Park (2015) studied AOD-9604, alone or with hyaluronic acid, in a rabbit model of knee osteoarthritis and reported lower cartilage degeneration scores than in saline controls.

These are short animal studies, most from the group that developed the compound. They do not show what AOD-9604 does in people.

The published research landscape

Outside the originating group, much of the recent literature on AOD-9604 is analytical. Doping-control and medicines laboratories need to identify the peptide and its breakdown products.

Cox et al. (2015), at a sports drug-testing laboratory in Salt Lake City, validated a urine detection method and identified six potential metabolites in serum and urine. A metabolite with the sequence CRSVEGSCG was markedly more stable than the parent peptide, which could widen the window of detection. The authors noted that the peptide was sold on websites and had been found in confiscated vials in the USA.
Orlovius et al. (2013), at the German Sport University Cologne, reported that AOD-9604 does not interfere with the WADA immunoassay for hGH isoforms.
Vanhee et al. (2014) described how Belgian medicines authorities identified AOD-9604 in seized preparations of unknown content.

A 2026 narrative review in Sports Medicine by Mendias and Awan placed AOD-9604 among unapproved peptides sold outside regulatory oversight and noted that rigorous human safety data for this group are scarce. The same pattern of analytical research appears in our TB-500 note.

Regulatory status

United States. AOD-9604 is not an FDA-approved drug. FDA's page on bulk drug substances that may present significant safety risks lists AOD-9604 among nominations that were withdrawn. FDA cites a possible risk of immunogenicity, complexities with peptide-related impurities, and no, or only limited, safety information. It also notes serious adverse events that may be associated with AOD-9604, though causality is not clear.
Sport. WADA's Prohibited List names AOD-9604 as an example of a growth hormone fragment under S2.2.3, prohibited at all times.
Elsewhere. We found no marketing authorisation for AOD-9604 from any major regulator as of 20 October 2026.

Open research questions

Mechanism. If AOD-9604 does not act through the hGH receptor or directly through beta-3 adrenergic receptors, the receptor or pathway behind the reported rodent findings remains unidentified.
Independent replication. Most mechanistic data come from one research group, and independent laboratories have published little on its biology.
Material identity. Seizure reports show that products sold under this name vary, so analytical identity and purity data matter for any laboratory work. Our guide How to read a peptide COA covers what such reports should contain.

For other metabolic compounds in the catalogue, see the notes on retatrutide and MOTS-c.

Limitations of the evidence

The rodent studies are short and come largely from the developing group.
No full peer-reviewed results of the company's human trials were found in PubMed.
Recent independent literature is mainly analytical chemistry for doping control.

Where researchers source it

Purita is a store that lists AOD-9604 for laboratory research use only. Its product page carries the label "For Research Use Only. Not for human or animal administration."

Purita product page

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