Short answer
AOD-9604 research peptide is a synthetic 16-amino-acid fragment corresponding to the C-terminal region of human growth hormone (hGH residues 177-191), modified with an additional N-terminal tyrosine. It is studied in metabolic research models for antilipogenic and lipolytic activity that is retained without binding the growth hormone receptor. It is sold as a lyophilized research powder and is not for human use.
What is the AOD-9604 research peptide?
AOD-9604 is a synthetic peptide derived from the C-terminal portion of human growth hormone (hGH). It corresponds to hGH residues 177-191, the 15-amino-acid sequence Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Glu-Gly-Ser-Cys-Gly-Phe, with an added N-terminal tyrosine (Tyr-hGH 177-191). With a molecular weight of approximately 1,817 Da, the peptide is small enough to be prepared by routine solid-phase peptide synthesis and is typically supplied as a lyophilized (freeze-dried) powder for reconstitution in the laboratory.
The compound was developed from structure-activity research on intact growth hormone. Early work in the laboratory of F.M. Ng at Monash University established that the functional domain responsible for the antilipogenic activity of growth hormone resides in the C-terminal region. Wu and Ng reported in 1993 that a synthetic peptide corresponding to the C-terminal sequence 177-191 of human growth hormone retained antilipogenic activity identical to that of the intact hormone, while showing no significant lipolytic effect as measured by glycerol release from rat epididymal fat pads [1]. This work provided the rationale for developing the modified fragment now known as AOD-9604.
AOD-9604 as a growth hormone fragment research subject
The design of AOD-9604 is instructive for researchers interested in growth hormone fragment research. Full-length hGH exerts a broad range of effects through the growth hormone receptor, including effects on linear growth, protein metabolism, and carbohydrate handling. By contrast, the C-terminal fragment 177-191 does not bind the growth hormone receptor, so its reported metabolic actions are studied as receptor-independent or indirectly mediated phenomena rather than canonical growth hormone signaling.
This is one reason the fragment attracted attention as a metabolic research peptide. In the published literature, the fragment and its modified derivative AOD-9604 have been examined for their ability to modulate lipid metabolism in adipose tissue, with studies reporting antilipogenic effects (reduced fat synthesis) and, in later modified-fragment work, lipolytic effects (increased fat breakdown) depending on the experimental model [2][3]. Researchers frame these results carefully, noting species differences and the fact that the peptide does not reproduce the full hormonal profile of intact growth hormone.
Mechanism of action: antilipogenic and lipolytic pathways
Two broad categories of reported effects appear in the AOD-9604 literature.
A key mechanistic study examined the beta-3 AR directly. Heffernan and colleagues treated obese mice and beta-3 AR knockout mice with human growth hormone or AOD-9604. Both compounds reduced body weight and fat mass in obese wild-type mice and increased expression of beta-3 AR messenger RNA in fat cells, restoring levels toward those seen in lean animals. In the knockout animals, the chronic effects on body weight and lipolysis were markedly reduced, although an acute effect of AOD-9604 on energy expenditure and fat oxidation remained. The authors concluded that the lipolytic actions are not mediated directly through the beta-3 AR, but that both hGH and AOD-9604 upregulate beta-3 AR expression, which may contribute to enhanced lipolytic sensitivity [4].
Research history of the hGH 177-191 fragment
The research history of AOD-9604 spans more than three decades. Early work in the 1980s and 1990s characterized the lipid-modulating properties of growth hormone fragments. The 1993 study by Wu and Ng remains a cornerstone, as it identified the C-terminal sequence as the antilipogenic domain of the hormone [1].
Building on that foundation, the Ng laboratory developed an orally active synthetic fragment and evaluated its effects on lipid metabolism in rodent obesity models. Heffernan and colleagues reported in 2000 that oral administration of the synthetic fragment reduced body weight gain in ob/ob mice from roughly day 16 onward, with no differences in food consumption between groups, and that the fragment reduced lipogenic activity and increased lipolytic activity in adipose tissue examined ex vivo. The same report described effects on isolated human adipose tissue in vitro [2].
In parallel, Ng and colleagues published metabolic studies of the synthetic lipolytic domain AOD-9604 in obese Zucker rats. Daily oral administration at 500 mcg/kg for 19 days reduced cumulative body weight gain by more than half relative to controls, and adipose tissue from treated animals showed increased lipolytic activity. No adverse effect on insulin sensitivity was detected using euglycemic clamp techniques, in contrast to the insulin resistance associated with intact growth hormone [3].
Later translational development brought the compound into clinical research settings. Published summaries of that program indicate that the compound was generally well tolerated in human studies, but that the larger randomized study did not reach statistical significance on its primary metabolic endpoint, and development as an anti-obesity candidate was discontinued. Researchers interested in the compound therefore focus on the preclinical mechanistic literature rather than clinical outcomes [2][3][4].
Research findings: in vitro and in vivo metabolic research
Across the peer-reviewed literature, the reported findings fall into several groups:
It is important to note that these are research-model findings. They describe what has been observed in controlled laboratory experiments on cells and animals, not established effects in any human population.
Interpreting the research record
A recurring point of emphasis in the AOD-9604 literature is the difference between rodent and human biology, particularly for the beta-3 adrenergic receptor. Beta-3 adrenergic signaling plays a much larger role in rodent lipolysis than it does in human white adipose tissue, so findings from beta-3 receptor knockout mice do not translate directly to human physiology. Researchers using AOD-9604 in their own models should therefore be explicit about the species they study and should not assume that a mechanism demonstrated in rodents is conserved across all systems.
A second interpretive point concerns the distinction between the preclinical and clinical record. The mechanistic studies cited above are peer-reviewed laboratory work in cells and animals. The broader clinical development program of the compound did not achieve its primary metabolic endpoint in a large randomized study, and development was subsequently discontinued. For the laboratory researcher, this means the value of the compound lies in the mechanistic, in-vitro, and animal-model literature, not in any claim about human outcomes.
AOD-9604 compared with related metabolic research peptides
For researchers designing metabolic studies, AOD-9604 sits alongside other peptides studied for their effects on energy metabolism. Growth hormone secretagogues such as the ghrelin-mimetic class act through the growth hormone secretagogue receptor and can influence food intake and energy balance. AOD-9604 is distinct in that it is a fragment of growth hormone itself rather than a secretagogue, and it does not bind the growth hormone receptor. For a category overview of compounds studied in this space, see metabolic research, and for a general introduction to the compound classes used in the field, our guide to what peptides are is a useful starting point. Researchers comparing appetite-related signaling may also find the GLP-1 research peptides buyer's guide helpful, since GLP-1 receptor agonists represent a different mechanistic axis of metabolic research.
How to evaluate quality when buying AOD-9604 for research
Research-grade AOD-9604 should come with verifiable quality data. Before ordering, confirm the following:
PEPMAKE provides batch documentation that researchers can review through the batch verification portal, and the AOD-9604 product page shows the kind of documentation supplied with each order. PEPMAKE products are supplied for in-vitro laboratory research only.
Storage and handling of lyophilized AOD-9604
Lyophilized AOD-9604 is most stable when stored cold and dry. Common laboratory guidance includes keeping the lyophilized powder in a freezer at or below -20 degrees C, protecting it from light and moisture, and minimizing repeated exposure to ambient temperature. Once reconstituted with an appropriate laboratory-grade solvent, the solution should be aliquoted to avoid repeated freeze-thaw cycles and stored according to the stability characteristics described for the material. Always consult the manufacturer's documentation and your own stability protocol, and keep the compound clearly labeled for research use only. Additional guidance on peptide storage is available in our peptide storage guide.
FAQ
What is AOD-9604?
AOD-9604 is a synthetic 16-amino-acid peptide derived from the C-terminal region of human growth hormone (hGH 177-191) with an added N-terminal tyrosine. It is sold for laboratory research only.
Is AOD-9604 the same as full growth hormone?
No. AOD-9604 is a fragment of the C-terminal region of growth hormone and does not bind the growth hormone receptor, so its reported effects are studied separately from full-length hormone signaling.
Is AOD-9604 for human use?
No. PEPMAKE sells AOD-9604 as a lyophilized powder for in-vitro laboratory research only. It is not for human or animal consumption.
What purity should research-grade AOD-9604 have?
At least 99% purity measured by HPLC, with identity confirmed by mass spectrometry and a batch-specific Certificate of Analysis (COA).