AOD-9604 has one of the stranger regulatory histories of any peptide. The FDA declared it safe enough to put in food in 2014 — then barred it from compounding pharmacies in 2023. In February 2026 it was moved back. This is a look at what the published literature on the compound reports, what the reclassification changed, and what it did not.
A note on what this article is. AOD-9604 is supplied by PepGenex strictly as a research-use-only material. Everything below describes published research on the compound. None of it is a claim about what the material supplied by PepGenex does, an instruction for using it, or a suggestion that it be used in or on a person. It is not for human or veterinary use.
What Is AOD-9604?
AOD-9604 is a synthetic fragment of human growth hormone — the C-terminal region spanning amino acids 176 to 191 — first isolated and modified by researchers at Monash University in Australia in the 1990s. The design goal was to separate the region of growth hormone associated with fat metabolism from the rest of the molecule. Much of what makes full-length growth hormone pharmacologically complicated — insulin suppression, bone and organ growth, IGF-1 elevation — is attributed to regions outside 176-191.
The literature therefore treats it as a comparatively narrow probe: a peptide studied for lipolytic signalling specifically, rather than for the broad activity of the parent hormone.
The Regulatory History
In 2014 the FDA granted AOD-9604 GRAS (Generally Recognized As Safe) status — the designation that permits an ingredient to be added to food. The decision drew on safety data accumulated during clinical development, including trials in adults that reported no significant adverse effects.
In 2023 the FDA placed AOD-9604 on its Category 2 compounding list — the category for substances the agency considered to raise safety questions or to lack evidence of clinical utility when compounded. The tension between the two decisions was widely noted at the time.
On February 27, 2026 it was announced that 14 of the 19 Category 2 peptides, AOD-9604 among them, would move back to Category 1. The public comment period closed June 29, 2026. That reclassification concerns the compounding pathway only. It did not make AOD-9604 an FDA-approved drug for any indication, and it has no bearing on material supplied for laboratory research, which is what PepGenex supplies.
Reported Mechanisms
Two mechanisms account for most of the published interest in the compound, and they are studied independently of the pathways GLP-1 receptor agonists act on.
Lipolysis
In laboratory models, AOD-9604 has been reported to act on beta-3 adrenergic receptors in adipose tissue, triggering release of stored triglycerides. In animal models the reported effect was most pronounced in visceral adipose tissue.
Lipogenesis
The same models report suppression of lipogenesis — the conversion of excess substrate into stored fat. Papers describing both effects characterise the result as acting on adipose tissue mass from two directions rather than one.
The fragment is reported not to bind IGF-1 receptors, not to suppress insulin production, and not to produce the growth-promoting effects associated with full-length growth hormone — the separation the Monash group set out to achieve.
What the Clinical Trial Record Shows
AOD-9604 completed Phase 2b trials in adults with obesity, reporting statistically significant fat loss against placebo — approximately 2-3 kg over 12 weeks. The programme did not continue: the compound did not meet the FDA's efficacy threshold for approval as a standalone obesity drug.
The distinction matters when reading the record. The trials were not halted over a safety finding; the compound was evaluated as a monotherapy, in an era before GLP-1 medications, and was not potent enough on its own to clear that bar. Those are the published results in humans, reported here as history. They are not a representation of what research material will do in any subsequent experiment.
Why the Mechanistic Literature Draws Comparisons to GLP-1 Pathways
GLP-1 receptor agonists act principally through appetite signalling, gastric emptying and insulin sensitivity. The beta-3 adrenergic and lipogenic pathways described above are separate. That non-overlap is the reason the two appear together in mechanistic discussion at all — the pathways are distinct, so the literature treats them as separate questions rather than as one.
Whether that separation amounts to anything in combination has not been established in controlled human studies. It remains an open mechanistic question, which is the only sense in which the comparison is made here.
Identity, Purity and Documentation
For research material, the questions that can actually be answered are about the vial, not about outcomes: what the compound is, how much of it is present, and whether that is documented.
- Identity and purity: tested lot by lot, with a Certificate of Analysis available on request.
- Stated content: net mass is stated on the container label and on the lot COA.
- Format: AOD-9604 is supplied lyophilized, to be reconstituted by the researcher.
AOD-9604 at PepGenex
PepGenex supplies AOD-9604 as a lyophilized research-use-only compound, listed in the research catalogue with its identity, lot documentation and stated content. It is not part of a treatment protocol, it is not dispensed through provider review, and it is not offered for any personal or clinical use. Qualified researchers can review the listing alongside the rest of the research line.
FOR RESEARCH USE ONLY. NOT FOR HUMAN OR VETERINARY USE. NOT FOR HUMAN CONSUMPTION. This article summarises published research for informational purposes. It is not medical advice, not a claim about any product, and not a protocol. AOD-9604 supplied by PepGenex is not a drug or a prescription medication, is not provided through a licensed provider or physician review, and is not intended to diagnose, treat, cure or prevent any disease. These statements have not been evaluated by the Food and Drug Administration.