NOT FDA-APPROVED

AOD-9604

A modified piece of growth hormone designed for fat loss without the rest of GH's effects. The defining fact: it failed its Phase 2b clinical trial for obesity in humans.

The 30-second read

AOD-9604 is a modified 16-amino-acid fragment of human growth hormone, designed in the 1990s to capture GH's fat-burning effect without the growth-promoting and blood-sugar-raising effects. The animal data was promising. The 2007 Phase 2b clinical trial for obesity failed: at 12 weeks, AOD-9604 did not produce statistically significant weight loss versus placebo. Metabolic Pharmaceuticals discontinued development. Despite that, and this is the unusual part. AOD-9604 has continued to circulate in research-peptide and compounding-pharmacy channels, sometimes pitched for fat loss the original trial did not support. Not FDA-approved. The Phase 2b failure is the most important data point on the page.

Why this peptide is on people's radar

The pitch behind AOD-9604 has always been elegant. Growth hormone has well-documented effects on fat metabolism, it stimulates lipolysis (fat breakdown) and reduces fat mass. But full GH also raises blood sugar, promotes tissue growth, and can have undesirable side effects when used for fat loss specifically. AOD-9604 was designed to be the "fat-burning fragment" only, the C-terminal piece (amino acids 176-191) of human GH thought to be responsible for the lipolytic effect, without the rest.

In animal models, this worked. AOD-9604 reduced fat mass in obese mice. Metabolic Pharmaceuticals (an Australian company) developed the compound and brought it through Phase 2 clinical trials. And then in 2007, the Phase 2b trial in humans for obesity failed. Twelve weeks of dosing did not produce statistically significant weight loss versus placebo. Metabolic Pharmaceuticals discontinued the obesity development program.

What's strange is that the molecule didn't disappear. Compounding pharmacies and research-peptide suppliers continued offering it. The fitness and biohacking communities adopted it as a fat-loss aid, often paired with growth-hormone secretagogues. Some marketers still cite the animal data without mentioning the Phase 2b failure. The honest framing: AOD-9604 is a peptide with a story that ended before it really began clinically, and it's still circulating despite that.

What people are usually trying to do with it

People exploring AOD-9604 are usually looking for:

  • Fat loss without using full growth hormone or GH-secretagogue stacks
  • A peptide that won't raise blood sugar or affect IGF-1
  • An adjunct to existing diet, training, and metabolic strategies
  • Cartilage-protective effects (a smaller body of preclinical research suggests this)
  • An option that's been around long enough to have a community track record (even if the trial track record is unfavorable)

What the science actually shows

The animal data is real and the human data is unfavorable. Plain-English summary:

Lipolytic effect in animals

Multiple animal studies in obese rodent models reported that AOD-9604 reduces fat mass and stimulates lipolysis without affecting growth or insulin sensitivity. The preclinical case for fat-burning specificity was reasonably strong.1

Phase 2b clinical trial, the failure

In 2007, a 12-week Phase 2b randomized trial of AOD-9604 in obese adults did not show statistically significant weight loss versus placebo. This is the defining piece of human evidence: the molecule did not deliver the result it was designed for.2

Cartilage and joint research

A smaller body of preclinical work has suggested AOD-9604 may have chondroprotective (cartilage-protective) effects, possibly relevant to joint and arthritis applications. This research is much less developed than the fat-loss program was.3

Safety profile

Across the trials that were conducted, AOD-9604 had a generally favorable safety profile. The reason development stopped was efficacy, not safety.4

What hasn't been demonstrated

Effective weight loss in humans at any dose tested. Replication of the animal-model effects in the rigorous human trial. Any FDA-recognized therapeutic role. Approval anywhere as a drug, despite Australia's TGA listing it as a "low risk" food ingredient (which is a different regulatory pathway and not a clinical endorsement).

The honest read

What's solid:

The mechanism is interesting and the animal data was real. The molecule is well-characterized. The safety profile from clinical trials is favorable. The cartilage-protective preclinical work is worth noting.

What's still unproven (or actively unsupported):

Effective fat loss in humans. The Phase 2b trial failure is the strongest piece of evidence on the page, and it's a negative one. Anyone marketing AOD-9604 for fat loss without acknowledging that trial outcome is selectively presenting the science.

What's hyped beyond the evidence:

Continued framing of AOD-9604 as an effective weight-loss peptide. The animal evidence didn't translate to humans in a rigorous trial. The TGA's listing of AOD-9604 as a low-risk food ingredient is a regulatory category about safety, not efficacy, citing it as evidence of weight-loss benefit is a misuse. The rise of GLP-1 medications has also made AOD-9604 essentially obsolete from any practical fat-loss standpoint.

Things to know if you're looking into it

  • How it's used in research: typically a daily subcutaneous injection. Some research-community protocols use morning fasted dosing.
  • Regulatory status: not FDA-approved. Listed as a "low-risk food ingredient" by Australia's TGA, that's a food-safety category, not a drug approval, and not evidence of weight-loss benefit. Not on the FDA Category 2 list.
  • The Phase 2b failure: the most important fact about this peptide. Anyone deciding what to do with it should know that the rigorous human trial for obesity did not show weight loss versus placebo.
  • Compared to GLP-1s: the contemporary GLP-1 class (semaglutide, tirzepatide) produces 15 to 25% weight loss in trials. AOD-9604 produced no statistically significant weight loss. There's no comparison on efficacy.
  • Reported tolerability: generally favorable safety profile from the clinical trial program. Side effects in research-community use are uncommon and mostly mild.
  • Healthcare provider involvement: recommended for any clinical decision. For anyone seriously trying to address obesity, the conversation about FDA-approved options is more relevant than this molecule.
  • Specific dosing protocols, mechanism, and the full reference list: all in the "Want to go deeper?" section below.

Reconstitution & dose calculator

Not FDA-approved. The Phase 2b clinical trial for obesity failed. The 2007 trial in obese adults did not show statistically significant weight loss versus placebo, and Metabolic Pharmaceuticals discontinued obesity development. The dose math below covers what's used in research-peptide and compounding-pharmacy circles, but the underlying premise — that AOD-9604 produces meaningful fat loss in humans — isn't supported by the rigorous human evidence. For people seriously addressing obesity, FDA-approved GLP-1s produce 15–25% weight loss; AOD-9604 produced none in trials. This is an educational reference, not dosing guidance.
Reconstitute with a mix of acetic acid water + BAC water, not BAC water alone. AOD-9604 is poorly soluble at neutral pH because of its arginine residues, so pure BAC water often produces incomplete dissolution. The standard community protocol for a 5 mg vial: 1 mL of 0.6% acetic acid water + 2 mL bacteriostatic water (3 mL total, 1.67 mg/mL). The BAC water still provides preservation; the acetic acid handles the solubility. Some increased viscosity or gel formation over time is normal for high-purity AOD-9604 and doesn't indicate degradation.
Suggested start
250 mcg/day
Lower end of community range
Common range
250–500 mcg/day
300 mcg is the most-cited mid-range dose
Max community dose
500 mcg/day
No evidence higher doses help — trial used standard doses
Cycle
8–12 wks on
Then reassess — trial duration was 12 weeks
mL
Defaults to 1.67 mg/mL on the 5 mg vial (3 mL total = 1 mL 0.6% acetic acid + 2 mL BAC water, the standard community protocol). The 2 mg and 10 mg vials use proportional volumes for the same 1.67 mg/mL. See the warning box above for why the AA + BAC mix matters.
mcg
Subcutaneous injection, once daily. Community protocols favor morning fasted dosing — eating around the dose blunts the GH-fragment effect on lipolysis. Wait at least 30–60 minutes before eating after injection.
Concentration
1.7 mg/mL
Per dose
0.15 mL
15 units on insulin syringe
Doses per vial
~20
~20 days (~2.9 weeks) of daily dosing

When to stay put vs. adjust — with the trial-failure caveat

Stay put at 250–300 mcg in the morning fasted for the first 4 weeks. AOD-9604's effects, if real in humans, are subtle and metabolic — the Phase 2b trial measured 12 weeks of dosing and didn't find a statistically significant signal at all. So if you're not seeing dramatic results in week 1, that's the expected pattern, not a reason to escalate.

Consider stepping to 400–500 mcg only after at least 4–6 weeks at the lower dose with no perceived effect. The trial failure happened at standard doses, so escalating doesn't have an evidence basis to suggest it'll work where the standard didn't — but if you're going to give the molecule a fair trial, the upper end of the community range is where to land before concluding it isn't doing anything.

Don't go above 500 mcg/day. No evidence higher doses help, and the case against is the trial failure: the molecule didn't work at the dose it was designed for, so pushing past that range is an inferential leap with no support.

Cycle off at the 12-week mark regardless of progress — that matches the trial duration and is also the practical decision point for "is this doing anything for me?" If 12 weeks at 300–500 mcg/day produced no measurable change in body composition, that's consistent with the trial result and a reasonable point to conclude AOD-9604 isn't your fat-loss tool.

Watch for injection-site reactions; that's about it. The clinical trial program reported a generally favorable safety profile — this is one of the cleanest peptide side-effect profiles on the site. Tolerability has never been the issue with AOD-9604; efficacy has.

The honest read — the most important paragraph on this calculator. AOD-9604's defining piece of human evidence is a Phase 2b trial that did not show statistically significant weight loss versus placebo. Metabolic Pharmaceuticals discontinued obesity development on that basis. The molecule has continued to circulate in research-peptide and compounding-pharmacy channels for nearly two decades despite that result. Anyone marketing AOD-9604 for fat loss is selectively presenting the science. If your goal is meaningful weight loss, FDA-approved GLP-1s (semaglutide, tirzepatide) produce 15–25% body weight loss in rigorous trials — AOD-9604 is not in the same category and the comparison isn't close. The dose math above is for completeness; the honest answer to "is this worth using for fat loss?" is "the rigorous human evidence says no."

For educational and research purposes only. This is not medical advice. AOD-9604 is not FDA-approved for any medical indication. The 2007 Phase 2b clinical trial for obesity failed to show statistically significant weight loss. Australia's TGA listing as a "low-risk food ingredient" is a food-safety category, not a drug approval or evidence of efficacy. For meaningful weight management, FDA-approved options should be the primary conversation. Consult a licensed healthcare provider before any health decision.

What people often ask

Does AOD-9604 actually work for fat loss?

The 2007 Phase 2b clinical trial in obese adults did not show statistically significant weight loss versus placebo. That's the strongest piece of human evidence and it's negative. Anecdotal community reports vary widely.

Why is it still around if the trial failed?

Compounding pharmacies and research-peptide suppliers continued offering it after Metabolic Pharmaceuticals discontinued obesity development. It found a second life in the fitness and biohacking communities, partly because the marketing emphasized the animal data and downplayed the Phase 2b result.

Is it FDA-approved?

No. Not approved as a drug for any indication.

What about TGA approval as a food ingredient?

Australia's TGA has listed AOD-9604 as a low-risk food ingredient, that's a safety-related regulatory category, not a drug approval, and not evidence of weight-loss efficacy. Citing it as proof the peptide works for fat loss is a misuse.

What about cartilage and joint applications?

A smaller body of preclinical work suggests AOD-9604 may have cartilage-protective effects, possibly relevant for osteoarthritis. This research is preliminary and far less developed than the fat-loss program was.

How does it compare to GLP-1s?

There's no real comparison on efficacy. GLP-1 medications (semaglutide, tirzepatide) produce 15 to 25% weight loss in rigorous trials. AOD-9604 produced no statistically significant weight loss in its Phase 2b trial.

Is it safe?

The clinical trial program reported a favorable safety profile. Long-term safety with continuous use in healthy adults isn't formally characterized, but acute and subacute safety from the trials looks reasonable.

FDA and regulatory status

Status as of May 5, 2026: Not FDA-approved for any medical indication. Phase 2b clinical development for obesity discontinued in 2007 following failed efficacy results. Listed as a "low-risk food ingredient" by Australia's TGA (a regulatory food-safety category, not a drug approval). Not currently on the FDA Category 2 list. Status updates land here when they happen.

Want to go deeper? Mechanism, dosing, the Phase 2b trial detail, side effects, and references. Click to expand.

Background and the failed clinical program

AOD-9604 ("Anti-Obesity Drug-9604") is a modified 16-amino-acid peptide corresponding to amino acids 176-191 of human growth hormone, with a tyrosine residue appended to the N-terminus. It was developed by Metabolic Pharmaceuticals Limited (Australia) based on research suggesting that the C-terminal region of GH was responsible for its lipolytic effects but not for its growth-promoting or diabetogenic effects.

The development program advanced through preclinical work and into human clinical trials. Phase 1 and Phase 2 studies suggested favorable safety. The Phase 2b efficacy trial in 2007, the pivotal study for advancing toward approval, failed to demonstrate statistically significant weight loss versus placebo at 12 weeks. Metabolic Pharmaceuticals discontinued the obesity-development program. The molecule has since circulated in compounding-pharmacy and research-peptide channels for fat loss without that clinical justification.

Mechanism of action

Lipolysis stimulation (preclinical)

In animal models, AOD-9604 stimulates lipolysis in adipose tissue and supports the breakdown of stored triglycerides into free fatty acids. The mechanism is thought to involve effects on β-adrenergic signaling pathways and possibly direct effects on adipocytes.

Lack of growth-promoting effects (preclinical)

Unlike full growth hormone, AOD-9604 in animal studies does not stimulate IGF-1 production, does not raise blood glucose, and does not promote linear growth. This was the key design goal, separating fat-loss effect from the rest of GH activity.

Failure to translate to humans

The mechanistic story didn't replicate in the human Phase 2b trial. Whether the mechanism is fundamentally different in humans, the dose was wrong, the duration too short, the patient population wrong, or the animal model not predictive, these questions would take more clinical work to answer, and that work didn't happen.

Studied and research-community dosing

These are not recommendations. Always consult a licensed healthcare provider before any clinical decision.

Phase 2 clinical trial range: doses of 1 mg daily oral or subcutaneous were used in different trial arms. The Phase 2b trial used a 1 mg subcutaneous daily dose for 12 weeks.

Research-community ranges: 250 to 500 mcg per day, given subcutaneously. Some users front-load with higher doses for the first few weeks, then taper.

Treatment duration: the failed trial was 12 weeks. Research-community cycles vary from a few weeks to several months. Long-term safety with continuous use in healthy adults has not been formally characterized.

Side effects and safety profile

Reported in the clinical-trial program and community use:

  • Mild injection-site reactions (uncommon)
  • Headache (uncommon)
  • Nausea (uncommon, mild)
  • Mild fatigue (uncommon)

Notably, AOD-9604 does not produce the GH-related side effects (carpal tunnel symptoms, edema, glucose intolerance) seen with full GH or some other GH-modulating peptides. The clinical-trial safety database is one of the more favorable parts of the AOD-9604 picture.

References

  1. Heffernan M, Summers RJ, Thorburn A, et al. (2001). "The effects of human GH and its lipolytic fragment (AOD9604) on lipid metabolism following chronic treatment in obese mice and beta(3)-AR knock-out mice." Endocrinology, 142(12), 5182–5189. PubMed
  2. Metabolic Pharmaceuticals Ltd. (2007). "AOD9604 Phase 2b clinical trial: Press release on missed efficacy endpoint and discontinuation of obesity development program." Public ASX disclosure.
  3. Hadden DR, et al. (2003). "Animal studies of AOD9604 in cartilage and joint repair models." Osteoarthritis Cartilage. PubMed
  4. Ng FM, Sun J, Sharma L, et al. (2000). "Metabolic studies of a synthetic lipolytic domain (AOD9401) of human growth hormone." Horm Res, 53(6), 274–278. PubMed
  5. Therapeutic Goods Administration (Australia). "AOD-9604, assessment as a food ingredient." TGA documentation. TGA.gov.au
For educational and research purposes only. This is not medical advice. AOD-9604 is not FDA-approved and failed its Phase 2b clinical trial for obesity in 2007. For people seriously trying to address obesity, FDA-approved options (semaglutide, tirzepatide) have substantially better-evidenced efficacy. PeptideLibraryHub is independent and does not sell peptides or accept money from anyone who does. Information current as of May 2026.