Research
What Is AOD-9604? The Growth Hormone Fragment Explained
AOD-9604 was designed to capture the fat-burning effect of growth hormone without its effects on blood sugar and growth. It reached large human trials in the 2000s, which is more than most research peptides can say, but those trials did not show meaningful weight loss. This guide explains what AOD-9604 is, what the research found, and where it stands today.
Reviewed for accuracy · Last reviewed October 19, 2026
What Is AOD-9604?
AOD-9604 stands for Anti-Obesity Drug 9604. It is a modified piece of the tail end of human growth hormone: amino acids 177 to 191, with an extra tyrosine added to the start for stability. It is closely related to the peptide sold as HGH Fragment 176-191.
It was developed by Metabolic Pharmaceuticals in Australia in the late 1990s, based on research at Monash University showing that this region of growth hormone was responsible for much of its effect on fat cells.
How Does AOD-9604 Work?
Full growth hormone has many effects: it builds tissue, raises IGF-1 and makes the body more resistant to insulin. AOD-9604 was designed to keep only the fat-related effects:
- Stimulates lipolysis: in fat-cell and animal studies, it increased the breakdown of stored fat.
- Reduces new fat formation: it reduced lipogenesis, the process of making new fat.
- No IGF-1 or blood sugar effect: unlike growth hormone, it did not raise IGF-1 or worsen insulin sensitivity in studies.
What Does the Research Show?
Animal studies. In obese mice and rats, AOD-9604 reduced body fat and weight gain without changing food intake.
Human trials. AOD-9604 completed several human trials. An early 12-week study suggested modest weight loss compared with placebo. A larger phase 2b trial involving more than 500 people with obesity, completed in 2007, found no significant weight loss compared with placebo. Metabolic Pharmaceuticals ended its obesity program afterwards.
Cartilage. Later animal studies in rabbits suggested AOD-9604 might support cartilage repair in osteoarthritis models. This has not been confirmed in human trials.
| Area | What studies show | Evidence type |
|---|---|---|
| Fat loss in obese rodents | Reduced body fat | Animal |
| Weight loss in people | No significant effect in phase 2b | Human RCT |
| Safety in people | Well tolerated in trials | Human RCTs |
| Cartilage repair | Positive signals | Animal |
AOD-9604 Safety and Side Effects
One upside of the failed trials is safety data. Across the human studies, AOD-9604 was generally well tolerated, with side effects similar to placebo. It did not raise IGF-1 or blood sugar. In 2014, a self-affirmed GRAS (generally recognized as safe) determination was published for its use as a food ingredient, which is a separate process from drug approval and does not mean it is an approved medicine.
Is AOD-9604 FDA-Approved?
No. AOD-9604 is not an FDA-approved drug and is not on the 503A Bulks List. It is also prohibited by WADA; it was at the center of a well-known Australian Football League doping scandal in 2013.
In April 2026, the FDA moved this substance out of its “Category 2” table of compounding ingredients that may present significant safety risks and into a separate table of substances whose nominations were withdrawn by the nominators. That move is not a finding that the substance is safe or effective, and it does not place it on the 503A Bulks List.
AOD-9604 vs HGH Fragment and GLP-1 Drugs
| Compound | Approach | Human weight-loss evidence |
|---|---|---|
| AOD-9604 | Modified GH fragment 177-191 | Phase 2b: no significant effect |
| HGH Fragment 176-191 | Unmodified GH tail fragment | Very limited |
| Growth hormone | Full hormone | Reduces visceral fat; raises IGF-1 and blood sugar |
| Semaglutide / tirzepatide | GLP-1 (and GIP) receptor agonists | 15–20%+ in phase 3 |
AOD-9604 vs HGH Fragment 176-191. These are nearly the same molecule. AOD-9604 has an added tyrosine and is the version that went through human trials. Research suppliers often treat them as interchangeable, but published data apply mainly to AOD-9604.
The bigger picture. When AOD-9604 was being developed, there were few effective obesity drugs. Today, GLP-1-based medicines produce far larger weight loss in large, well-controlled trials.
Buying Research-Grade AOD-9604: What to Check
Products sold as AOD-9604 by research suppliers are laboratory chemicals, not medicines. They are not made under drug manufacturing rules, so quality varies a lot between vendors. If you are evaluating an AOD-9604 supplier for lab research, these are the checks that matter:
- Batch-specific COA: the certificate should match the lot number on your vial, not a generic sample.
- Independent lab: testing should come from a named third-party lab, ideally with a way to verify the report online.
- Identity, not just purity: HPLC purity alone does not confirm the right molecule; look for mass spectrometry (MS) identity confirmation.
- Endotoxin and sterility results: these matter for any injectable research material.
- Correct fill amount: the measured content should be close to the labeled milligrams.
Our Trusted Sources page lists vendors we track, with current community codes. Our guide to reading a certificate of analysis explains each line of a COA.
Key Takeaways
- AOD-9604 is a modified fragment of growth hormone designed for fat loss.
- It increased fat breakdown in animals without raising IGF-1 or blood sugar.
- A phase 2b trial in more than 500 people found no significant weight loss.
- It was well tolerated in human studies.
- It is not FDA-approved and is banned in sport.
Frequently Asked Questions
What is AOD-9604?
AOD-9604 is a modified fragment of human growth hormone (amino acids 177–191 plus a tyrosine) developed to promote fat loss without growth hormone’s other effects.
Does AOD-9604 work for weight loss?
It reduced body fat in animals, but a phase 2b trial in more than 500 people found no significant weight loss compared with placebo.
Is AOD-9604 the same as HGH Fragment 176-191?
They are nearly identical. AOD-9604 has an added tyrosine and is the version that was tested in human trials.
Is AOD-9604 safe?
In human trials it was generally well tolerated and did not raise IGF-1 or blood sugar. Long-term safety outside trials is not established.
Is AOD-9604 FDA-approved?
No. It is not an approved drug and is prohibited in sport by WADA.
Sources
- Heffernan et al. (2001) – The effects of human GH and its lipolytic fragment (AOD9604) on lipid metabolism, Endocrinology
- Stier et al. (2013) – Safety and tolerability of the hexadecapeptide AOD9604 in humans, Journal of Endocrinology and Metabolism
- Kwon & Park (2015) – AOD9604 and cartilage regeneration in a rabbit osteoarthritis model
- FDA – Certain bulk drug substances for use in compounding that may present significant safety risks (updated April 22, 2026)
MLCR SCTY provides educational information, not medical or legal advice. Research-use-only products are not intended for human consumption.