AOD-9604 is a 16-amino-acid synthetic peptide based on the C-terminal end of human growth hormone (hGH). It was developed in Melbourne in the 1990s to test whether the fat-metabolism activity of growth hormone could be separated from its effects on growth and IGF-1.
Rodent studies reported effects on lipid metabolism, but a larger human obesity trial did not meet its endpoints, and development for obesity was stopped in 2007. It remains an investigational compound and is not approved by the FDA.
At a glance
| Also known as | AOD9604, Tyr-hGH(177–191) |
| Sequence | YLRIVQCRSVEGSCGF, with a Cys–Cys disulfide bond |
| Length | 16 residues |
| Molecular weight | ≈1,815 Da |
| Derived from | Residues 177–191 of human growth hormone, with an added N-terminal tyrosine |
| Growth hormone receptor | No activity reported |
| US status | Not FDA-approved; research use only |
Why a growth hormone fragment
Growth hormone has two broad kinds of activity: growth-promoting effects that run through the GH receptor and IGF-1, and metabolic effects including the breakdown of stored fat. Work at Monash University in the 1990s suggested that a small region near the C-terminus of hGH carried some of the lipolytic activity on its own.
AOD-9604 was designed around that region. The aim was a molecule that kept the effect on fat metabolism without binding the growth hormone receptor, raising IGF-1 or reproducing growth hormone’s effects on insulin and blood glucose.
Structure
The peptide corresponds to residues 177–191 of hGH with a tyrosine added at the N-terminus, which is why the original literature writes it as Tyr-hGH(177–191). The two cysteines form an intramolecular disulfide bond, creating a loop similar to the one at the end of native growth hormone.
In the research-peptide market the name “HGH Fragment 176–191” is often used for the same 16-residue sequence. Strictly, native hGH has phenylalanine at position 176, so the tyrosine-containing peptide is best identified by its sequence. Checking the sequence and mass on the certificate of analysis avoids confusion between the two.
What the research has looked at
Rodent fat metabolism. Studies in obese mice reported reduced body-weight gain and increased lipolysis and fat oxidation with chronic AOD-9604 treatment, without the changes in IGF-1 or insulin sensitivity seen with full-length growth hormone.
The β3-adrenergic question. A 2001 study in Endocrinology found that both hGH and AOD-9604 increased β3-adrenergic receptor expression in fat tissue. In β3-receptor knockout mice, however, chronic treatment no longer changed body weight, while an acute increase in fat oxidation was still seen. The authors concluded that the effects are not mediated directly through the β3 receptor, and the mechanism remains incompletely characterized.
Cartilage models. After the obesity program ended, the developer shifted to musculoskeletal research. A 2015 study in a rabbit model of collagenase-induced knee osteoarthritis compared intra-articular injections of AOD-9604, hyaluronic acid and the two combined.
The human trial history
AOD-9604 progressed into human trials in the early 2000s. An earlier 12-week study reported a small difference from placebo, but a larger 24-week trial with several hundred participants found no significant weight loss compared with placebo at any dose tested. In 2007 the developer, Metabolic Pharmaceuticals, discontinued development of AOD-9604 as an obesity treatment. Those results were disclosed by the company rather than published in full in a peer-reviewed journal.
Handling in the lab
AOD-9604 is supplied as a lyophilized powder. Lyophilized peptides are normally kept frozen, dry and away from light, and once reconstituted are kept refrigerated and used within a short window. See our reconstitution protocol for technique, and bacteriostatic vs sterile water for diluent choice.
Frequently asked questions
What is AOD-9604?
A 16-residue synthetic peptide based on residues 177–191 of human growth hormone with an added N-terminal tyrosine, studied for effects on fat metabolism in rodents.
Is AOD-9604 the same as HGH Fragment 176–191?
They are often sold under either name for the same sequence. AOD-9604 is precisely Tyr-hGH(177–191); native hGH carries phenylalanine at 176. Confirm identity from the sequence and mass on the certificate.
Does AOD-9604 act on the growth hormone receptor?
The published work reported no binding to the growth hormone receptor and no increase in IGF-1. No other receptor for the fragment has been identified.
Is AOD-9604 FDA approved?
No. Human obesity trials did not meet their endpoints and the compound is not an approved drug. Isla Longevity supplies it for laboratory research only.
Purity and certificates
Every batch ships with a third-party certificate of analysis, published by batch number in our COA Bank. View AOD-9604 and its current COA. New to reading certificates? Start with how to read a certificate of analysis.
Related reading: What is Tesamorelin? · What is CJC-1295 + Ipamorelin? · How to read a COA
References
- Ng FM, Sun J, Sharma L, et al. Metabolic studies of a synthetic lipolytic domain (AOD9604) of human growth hormone. Horm Res. 2000;53(6):274–278.
- Heffernan M, Summers RJ, Thorburn A, et al. The effects of human GH and its lipolytic fragment (AOD9604) on lipid metabolism following chronic treatment in obese mice and β3-AR knock-out mice. Endocrinology. 2001;142(12):5182–5189.
- Kwon DR, Park GY. Effect of intra-articular injection of AOD9604 with or without hyaluronic acid in rabbit osteoarthritis model. Ann Clin Lab Sci. 2015;45(4):426–432.
Research use only
Isla Longevity supplies this compound for laboratory research use only. It is not approved by the FDA for human or veterinary use and is not for human consumption. This article summarises published research and is not medical guidance.
