AOD9604 Research Guide — hGH Fragment 176-191 (UK 5mg)

What is AOD9604?

AOD9604 (Advanced Obesity Drug 9604) is a synthetic peptide corresponding to the C-terminal region of human growth hormone (hGH) — specifically amino acids 176–191 — with a small structural modification (an added tyrosine residue) to improve stability. It belongs to a class of compounds studied for their effect on fat metabolism, and is notable in the research literature for reproducing the lipolytic (fat-mobilising) activity of growth hormone without the broader growth-promoting or glucose-related effects of the full hGH molecule.

Because it isolates one functional region of a much larger protein, AOD9604 is often described as a “fragment” peptide. This guide summarises what the fragment is, the biology researchers have used it to probe, and the published trial history — for laboratory research use only.

Origin: The hGH 176–191 Fragment

Full human growth hormone is a 191-amino-acid protein with several functionally distinct regions. Work in the 1990s established that the metabolic (lipolytic) actions of hGH could be traced largely to its C-terminus, while its growth-promoting actions (mediated through IGF-1) mapped to other parts of the molecule. AOD9604 was developed at Monash University and Metabolic Pharmaceuticals in Australia to capture the fat-metabolism region — residues 176–191 — as a standalone, more stable peptide.

The design goal was a compound that engaged fat-cell metabolism in the way growth hormone does, but without stimulating the IGF-1 axis, cell proliferation, or the insulin-antagonising effects associated with chronic elevated hGH. That separation of effects is the central reason AOD9604 remains an object of interest in metabolic research.

Mechanism: Lipolysis Without the Growth Axis

In preclinical models, AOD9604 has been reported to stimulate lipolysis (the breakdown of stored triglyceride into free fatty acids) and inhibit lipogenesis (the formation of new fat), mirroring the C-terminal metabolic signature of growth hormone.

β3-Adrenergic Signalling and Fat Metabolism

Research has linked the fragment’s activity to β3-adrenergic receptor–associated pathways in adipose tissue, which regulate the mobilisation of stored fat. Rather than acting as a growth-hormone-receptor agonist in the classical sense, AOD9604’s reported effects centre on fat-cell energy handling — a distinction that makes it a useful tool for isolating the metabolic component of GH biology in the laboratory.

Why It Doesn’t Raise IGF-1 or Blood Glucose

A defining feature reported across studies is that AOD9604 does not meaningfully raise circulating IGF-1 and does not produce the glucose-handling changes seen with full growth hormone. This is the property that distinguishes the fragment from GH secretagogues such as Ipamorelin or GHRH analogues like Tesamorelin, which act upstream to increase endogenous GH (and therefore IGF-1) output. AOD9604 sits in a different mechanistic category — a downstream metabolic fragment rather than a secretagogue.

The Research Literature

Preclinical Findings

In rodent and in-vitro models, AOD9604 has been reported to reduce body fat, increase fat oxidation, and act on adipocytes to shift the balance toward lipolysis. These findings established the fragment as a proof-of-concept that the metabolic and somatogenic (growth) actions of hGH can be pharmacologically separated.

Clinical Trial History

AOD9604 progressed to human trials as an investigational anti-obesity candidate. Early-phase studies reported a favourable safety and tolerability profile with no significant effect on IGF-1 or glucose. However, later controlled trials did not demonstrate weight-loss efficacy above placebo sufficient to meet their primary endpoints, and the compound was not advanced to market as an obesity therapeutic. It has since been examined in other contexts (including cartilage and metabolic research). Researchers should note this trial history when interpreting the compound’s profile: a clean safety signal, but unproven efficacy for the original indication.

Comparison with Other Metabolic Peptides

AOD9604	hGH C-terminal fragment (176–191). Acts downstream on fat metabolism; does not raise IGF-1.
Tesamorelin	GHRH analogue. Acts upstream to increase endogenous GH and IGF-1; studied for visceral adipose tissue. See the Tesamorelin guide.
Ipamorelin	Selective GHRP/ghrelin-receptor agonist; pulsatile GH release. See the Ipamorelin guide.
MOTS-c	Mitochondrial-derived peptide studied in metabolic and exercise biology. See the MOTS-c guide.

The key conceptual point: AOD9604 is the only one of these that is a fragment of GH itself acting on fat cells directly, rather than a signal that tells the body to make more of its own growth hormone.

Experimental Considerations

AOD9604 is supplied as a lyophilised (freeze-dried) powder for reconstitution. As with other research peptides, handling directly affects data quality:

Reconstitution — prepare with bacteriostatic water following standard technique; see the Peptide Reconstitution Guide for volume and concentration calculations.
Storage — keep lyophilised vials cold and protected from light; reconstituted solution is short-lived and should be refrigerated. See Peptide Storage best practices.
Purity — OLR’s AOD9604 5mg is supplied at ≥99% HPLC purity, UK-dispatched. Purity and correct reconstitution are the two biggest determinants of reproducible results.

Frequently Asked Questions

Is AOD9604 the same as growth hormone?
No. It is a 16-amino-acid fragment corresponding to the C-terminus (176–191) of human growth hormone, isolating the fat-metabolism region without the full molecule’s growth or glucose effects.

Does AOD9604 raise IGF-1?
The research literature reports that it does not meaningfully change circulating IGF-1 — a key difference from GH secretagogues like Tesamorelin or Ipamorelin.

Was AOD9604 ever approved as a weight-loss drug?
No. Despite a favourable safety profile in trials, it did not meet weight-loss efficacy endpoints and was not brought to market as an obesity therapeutic. It remains a research compound.

What is AOD9604 used for?
In the UK it is supplied strictly as a laboratory research chemical for in-vitro and preclinical study. It is not for human or veterinary use.

AOD9604 Research Guide — hGH Fragment 176-191