AOD-9604

What it is

AOD-9604 is a synthetic peptide corresponding to the C-terminal region of human growth hormone, specifically residues 176-191, with a small modification at one end S3S4. It is described as a lipolytic fragment of growth hormone, meaning it was designed to carry the fat-metabolizing signal attributed to the parent hormone S3. A frequently cited distinction is that the fragment was reported to retain lipolytic activity without stimulating IGF-1 production, so it lacks the growth-promoting and proliferative activity of full growth hormone S4. It was developed by an Australian company, Metabolic Pharmaceuticals, as an investigational anti-obesity agent S1S4.

Marketed as

The claims in this section are marketing claims, not established effects. AOD-9604 is promoted to consumers and by some wellness clinics as a fat-loss or weight-loss peptide, and is often framed as a "fat-burning" growth-hormone fragment S1. Some marketing extends to joint or recovery benefits S1. These positioning claims are not supported by a successful pivotal human trial, and the original obesity program was terminated after its efficacy studies (see Evidence) S1S4.

Regulatory status (US)

AOD-9604 is not FDA-approved for any use S1. The FDA evaluated AOD-9604 (free base and acetate form) for possible inclusion on the 503A bulk drug substances list used in pharmacy compounding, and found the substance not well physically and chemically characterized, with limited safety data; the agency's evaluation criteria weighed against placing it on that list, pending advisory-committee input S1. With no approved indication, it circulates through gray-market and compounding channels rather than as an approved drug S1.

Around the world

The compound originated in Australia, where Metabolic Pharmaceuticals developed it and where the obesity program was halted in 2007 after its trials S4. Australia's Therapeutic Goods Administration did not approve an obesity indication for it S1S4. In the years that followed it existed in a regulatory gray zone as a substance that had not been approved for general human therapeutic use, a status that later became central to a sports controversy S5.

Evidence

Preclinical work in obese mice reported that AOD-9604, like growth hormone, reduced body weight and enhanced fat breakdown, while also indicating that these lipolytic actions were not mediated directly through the beta-3 adrenergic receptor S3. In humans the picture is weaker: early studies suggested a modest signal, but the later, longer pivotal trial did not show a significant weight-loss benefit versus placebo, and that failure ended development S1S4. Regulators have summarized the human efficacy evidence as poor, noting that studies failed to demonstrate meaningful weight loss compared with placebo S1. The overall evidence stage is therefore mixed — some supportive preclinical data against unconvincing human outcomes S1S3.

Anti-doping

Under the current WADA 2026 Prohibited List, growth hormone fragments are prohibited, and AOD-9604 is named as an example: the List's Section S2 language cites "growth hormone fragments, e.g. AOD-9604 and hGH 176-191" as prohibited at all times (in and out of competition) S2. This present-day status is settled and should not be confused with the disputed advice of the Essendon-era controversy (2012-2013), when the substance's status was publicly contested before authorities stated it had been treated as prohibited S5. On detection, research found that AOD-9604 does not register on the standard WADA hGH isoform immunoassay, so dedicated analytical methods are used to detect it S6.

Safety

Human safety data for AOD-9604 are limited S1. In its evaluation the FDA flagged concerns arising from limited nonclinical data, including animal-study signals related to bone-turnover markers, liver findings in monkeys, and equivocal genotoxicity signals, together with an unknown mechanism for the proposed effect S1. Because it is unapproved and largely supplied through compounding or gray-market routes, product identity, purity, and manufacturing quality are not assured S1. It has not been established as safe for human therapeutic use S1.

What's changing

The active development to watch is the FDA pharmacy-compounding review, where the agency's evaluation currently trends against listing AOD-9604 as a bulk drug substance for compounding S1. Despite the lack of approval and the prohibited status in sport, marketing and clinic availability persist, which is why the gap between promotional claims and the regulatory and evidence record remains the central story S1S2.