AOD-9604
A 16-amino-acid piece of growth hormone that trimmed fat in obese rodents without touching blood sugar; six company trials in about 900 adults found it well tolerated, and the largest found no significant weight loss
AOD-9604 is residues 177 to 191 of human growth hormone with a tyrosine added at the front, which makes it the same sequence as residues 176 to 191. In obese rats and mice it reduced weight gain and increased fat breakdown without the high blood sugar that whole growth hormone causes, and it does not bind the growth hormone receptor. Its developer, Metabolic Pharmaceuticals, ran six placebo-controlled trials in Australia between 2001 and 2006. It was well tolerated and did not raise IGF-1, but a 24-week trial in 536 adults found no significant weight loss, and development for obesity stopped in 2007. It was never approved.
What is it?
Growth hormone breaks down fat, but it also raises blood sugar, causes insulin resistance and drives growth through IGF-1, which is why it is not used to treat obesity. Researchers traced its fat-mobilising action to a region near the C-terminal end, residues 177 to 191, that seemed to work on its own. AOD-9604 is that stretch with a tyrosine added to the front to stabilise it. Because growth hormone's residue 176 is itself a tyrosine, the result is identical to the fragment sold as 'HGH fragment 176-191': one molecule, with one formula and mass.
In animals it did what it was designed to do. Obese Zucker rats given 500 µg/kg by mouth every day for 19 days gained less than half as much weight as controls, and their fat tissue broke down fat faster, with no loss of insulin sensitivity on a glucose clamp. In obese mice two weeks of treatment reduced body weight and fat and raised fat oxidation. Unlike growth hormone it did not cause hyperglycaemia, did not compete for the growth hormone receptor and did not make receptor-bearing cells multiply. It raised the fat cell's beta3-adrenergic receptor, but it still increased fat burning in mice lacking that receptor.
The human programme was built around taking it by mouth. A 2013 report by the developer's consultant and two people tied to the company summarised six randomized, placebo-controlled trials run in Australia between 2001 and 2006, in 893 adults, all but one trial in people with obesity: two with single intravenous doses of 25 to 400 µg/kg, then oral doses from 0.25 to 54 mg a day, the longest lasting 24 weeks. Serum IGF-1 did not change, glucose tolerance tests did not worsen, no antibodies against the peptide were found, and the investigators judged no serious adverse event related to it. The report covers safety only and leaves out the weight results the two long trials were designed to measure.
Those results are recorded elsewhere. A 2010 review in Clinical Pharmacology & Therapeutics reports that in a 12-week trial people taking 1 mg a day lost 2.6 kg against 0.8 kg on placebo, that the effect did not rise with dose, and that development was terminated in 2007 because a 24-week trial of 536 people produced no significant weight loss (the company's safety report counts 534 people enrolled and 502 randomized in that trial). A panel convened for the developer later judged it 'generally recognized as safe' for use in foods, which is a self-determination and not an FDA decision, and in 2009 another company took an option to license it as a cosmetic ingredient. Sold today as a fat-loss injection, it is being used by a route and at doses no published trial tested.
Mechanism of Action
AOD-9604 is a piece of growth hormone that keeps the fat-mobilising action and drops the rest. The pathways below come from rodent studies, except the last, which comes from the company's human trials.
No growth hormone receptor
Whole growth hormone needs two binding sites to pair two receptors and switch them on. AOD-9604 carries only part of one. In cells engineered to carry the growth hormone receptor it did not compete with growth hormone for binding and did not make the cells proliferate, so its actions run through some other route that has not been identified.
Fat breakdown and fat burning
In obese rats and mice it reduced weight gain, increased the fat tissue's lipolytic activity and raised plasma glycerol, a marker of fat breakdown, and whole-body fat oxidation. In obese Zucker rats this happened with an oral dose, which is why the developer pursued a pill.
The beta3-adrenergic question
Treatment restored the depressed beta3-adrenergic receptor RNA of obese mice to lean levels, and long-term treatment did not reduce weight in mice lacking that receptor. Yet a single dose still raised energy expenditure and fat oxidation in those knockout mice, so the authors concluded its fat-burning action is not mediated directly through the receptor.
No IGF-1, no rise in blood sugar
Growth hormone's unwanted effects run largely through IGF-1 and insulin resistance. In rodents AOD-9604 caused no hyperglycaemia and did not reduce insulin sensitivity. In the company's human trials serum IGF-1 did not change over 12 and 24 weeks and oral glucose tolerance tests did not worsen.
Published Research
PubMed lists 23 records for AOD-9604, and none reports a human trial. The human evidence comes from the developer's 2013 safety report in a journal PubMed does not index and from a 2010 review that records the weight results. The five cards below are three animal studies, a laboratory study and a drug-development profile. Four more papers are in the References: a 2001 mouse study titled for 'a modified C-terminal fragment', two anti-doping reports with no abstract, and the 2010 review.
Obese rats, dosed by mouth
Obese Zucker rats given AOD9604 by mouth at 500 µg/kg a day for 19 days gained 15.8 g against 35.6 g in controls, a reduction of more than half. Their fat tissue showed more lipolytic activity, and a euglycaemic clamp showed no loss of insulin sensitivity, unlike chronic treatment with whole growth hormone.
The beta3-adrenergic question
In obese mice, 14 days of growth hormone or AOD9604 by injection reduced body weight and fat and raised beta3-adrenergic receptor RNA to lean levels. In mice lacking that receptor, long-term treatment changed neither weight nor lipolysis, but a single dose of AOD9604 still increased energy expenditure and fat oxidation, so its action is not mediated directly through the receptor.
A drug in development
A 2004 drug-development profile records that Metabolic was developing AOD-9604 as a potential obesity treatment and that phase IIa trials were under way by February 2002.
Testing athletes for it
Chemists validated a urine test for AOD9604 with a detection limit of 50 pg/mL and identified six breakdown products after incubating it in serum and urine. One metabolite, the nine-residue CRSVEGSCG, was far more stable than the parent peptide, so testing for it could widen the detection window. The authors note that the peptide is sold online, had been found in confiscated vials in the USA, and is banned in sport.
Rabbit knees with arthritis
In 32 rabbits with collagenase-induced knee osteoarthritis, weekly injections into the joint of 0.25 mg AOD9604, 6 mg hyaluronic acid or both gave lower cartilage damage scores than saline, and the combination beat either alone and shortened lameness. It is the only joint study, it was in rabbits, and no human study has followed.
What people say, and what was measured
AOD-9604 is a fragment of growth hormone sold for fat loss. Its own developers tested it in people and development stopped. The marketing kept the mouse results and dropped that ending.
It is the fat-burning part of growth hormone without the side effects.
Heard in: Grey Peptides listing review, October 1, 2026: listings describe it as the lipolytic fragment of hGH, without hGH's drawbacks. Sellers are not named.
The first half is the original claim and it was shown in mice: AOD9604 reduced weight gain and raised lipolytic activity in fat tissue, and unlike intact growth hormone it did not harm insulin sensitivity on clamp testing. A second mouse study found its lipolytic action is not mediated directly through the beta-3 adrenergic receptor. Mice throughout. PMID: 11146367, 11713213, 11673763
Shown in animals or cells onlyIt is a proven obesity treatment.
Heard in: Current Opinion in Investigational Drugs, the development review of AOD-9604 as a metabolic candidate (read October 1, 2026). Source
It reached clinical development and did not come out the other side. The published record on this entry is a development review and a broader survey of molecular targets for anti-obesity drugs; no positive human obesity trial appears here, and the compound is approved nowhere. PMID: 15134286, 20445536
Never tested in peopleIt helps joints and cartilage.
Heard in: Grey Peptides listing review, October 1, 2026: listings add joint and cartilage repair to the fat-loss claim. Sellers are not named.
One rabbit study injected AOD9604 into the joint with or without hyaluronic acid. That is the whole basis, and it is one animal study. PMID: 26275694
Shown in animals or cells onlyIt is undetectable, so it is safe for tested athletes.
Heard in: Grey Peptides listing review, October 1, 2026: listings mention that it does not trigger growth hormone tests. Sellers are not named.
It is true that AOD-9604 does not influence the WADA growth hormone isoform immunoassay — and that is exactly why a dedicated detection method was built. Six metabolites were identified, one of them markedly more stable than the parent compound, specifically to widen the detection window. The peptide has also been found in seized unknown pharmaceutical preparations. PMID: 24124033, 25208511, 24976118
Contradicted by the ruleEach claim is quoted from where it is said, never from a seller, and checked as of October 1, 2026 against the studies listed below.
Dosing Data
AOD-9604 has no approved dose. The company trials gave it by mouth, from 0.25 to 54 mg a day, or as single intravenous doses of 25 to 400 µg/kg; the longest lasted 24 weeks. Daily injections under the skin, the way it is sold now, were never tested, and the microgram amounts in circulation are community figures.
Educational information, not medical advice. Each dose above is tagged with its source: an approved label, a published human study, animal data, or amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
→ Full AOD-9604 dosage guide — the community figures, the oral and intravenous doses the company trials used, and why neither is an injected dose.
Side Effects & Contraindications
Reported Side Effects
From the company's six trials (2013 report) and FDA's compounding safety page.
Contraindications & Cautions
No trial defined who should avoid AOD-9604. These cautions follow from what was and was not studied.
Legal Status
AOD-9604 is not approved as a medicine anywhere. Status as of September 27, 2026.
Frequently Asked Questions
?Does AOD-9604 work for weight loss?
In obese rats and mice it reduced weight gain. In people, a 2010 review reports that a 12-week trial found 2.6 kg lost on 1 mg a day against 0.8 kg on placebo, with no dose response, and that a 24-week trial of 536 people found no significant weight loss, after which development for obesity was terminated in 2007.
?Is AOD-9604 the same as HGH fragment 176-191?
Yes. AOD-9604 is growth hormone residues 177 to 191 with a tyrosine added at the front, and growth hormone's residue 176 is a tyrosine, so the sequence is identical: YLRIVQCRSVEGSCGF, C78H123N23O23S2, 1815.1 g/mol with its disulfide bond. AOD9401, sometimes listed as a synonym, is a different, shorter fragment.
?Is AOD-9604 safe?
In six company trials in 893 adults, mostly taking it by mouth for up to 24 weeks, it was well tolerated: no change in IGF-1 or glucose tolerance, no antibodies, and no serious adverse event judged related. The report was written with the developer, covers oral and intravenous use rather than injections under the skin, and records five tumours in one trial, four of them cancers, that the investigator judged unrelated. FDA notes immune-reaction risk and serious adverse events of unclear cause for compounded use.
?Does AOD-9604 raise IGF-1 or blood sugar like growth hormone?
Not in the studies. It does not bind the growth hormone receptor, caused no hyperglycaemia in rodents, and in the company's human trials serum IGF-1 did not change over 12 and 24 weeks while oral glucose tolerance tests did not worsen.
?Is AOD-9604 FDA-approved or GRAS?
It is not approved as a drug anywhere. A panel convened for the developer judged it 'generally recognized as safe' for intended uses in foods; a GRAS determination made that way is the company's own conclusion, not an FDA approval, and it does not cover injection.
?Can AOD-9604 help joints or cartilage?
One study has asked. In 32 rabbits with chemically induced knee osteoarthritis, weekly injections into the joint reduced cartilage damage, and adding hyaluronic acid worked better than either alone. There is no human study.
?Can drug tests detect AOD-9604?
Yes. A validated urine test detects it down to 50 pg/mL, and a stable nine-residue breakdown product can extend the detection window. It also does not interfere with the growth hormone isoform test. Its status in sport is in the legal table on this page, from our regulatory tracker.
References
- [clinical-trial] Stier H, et al. "Safety and tolerability of the hexadecapeptide AOD9604 in humans." J Endocrinol Metab, 2013;3(1-2):7-15. doi:10.4021/jem157w (not PubMed-indexed; read in full September 27, 2026).
- [pubmed] Ng FM, et al. "Metabolic studies of a synthetic lipolytic domain (AOD9604) of human growth hormone." Horm Res, 2000;53(6):274-8. PMID: 11146367.
- [pubmed] Heffernan M, et al. "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, 2001;142(12):5182-9. PMID: 11713213.
- [pubmed] Wilding J. "AOD-9604 Metabolic." Curr Opin Investig Drugs, 2004;5(4):436-40. PMID: 15134286.
- [pubmed] Cox HD, et al. "Detection and in vitro metabolism of AOD9604." Drug Test Anal, 2015;7(1):31-8. PMID: 25208511.
- [pubmed] Kwon DR, et al. "Effect of Intra-articular Injection of AOD9604 with or without Hyaluronic Acid in Rabbit Osteoarthritis Model." Ann Clin Lab Sci, 2015;45(4):426-32. PMID: 26275694.
- [pubmed] Heffernan MA, et al. "Increase of fat oxidation and weight loss in obese mice caused by chronic treatment with human growth hormone or a modified C-terminal fragment." Int J Obes Relat Metab Disord, 2001;25(10):1442-9. PMID: 11673763.
- [pubmed] Orlovius AK, et al. "AOD-9604 does not influence the WADA hGH isoform immunoassay." Drug Test Anal, 2013;5(11-12):850-2. PMID: 24124033.
- [pubmed] Vanhee C, et al. "Identification and characterization of peptide drugs in unknown pharmaceutical preparations seized by the Belgian authorities: case report on AOD9604." Drug Test Anal, 2014;6(9):964-8. PMID: 24976118.
- [pubmed] Valentino MA, et al. "Central and peripheral molecular targets for antiobesity pharmacotherapy." Clin Pharmacol Ther, 2010;87(6):652-62. PMID: 20445536.
- [other] U.S. Food and Drug Administration. Certain bulk drug substances for use in compounding that may present significant safety risks (AOD-9604, among nominations withdrawn). Content current as of April 22, 2026; read September 27, 2026.
Sources & Citations
Every PubMed citation on this page has been checked against its record. The company's 2013 safety report appears in a journal PubMed does not index and was read in full; FDA's compounding safety page is cited as published. Our earlier entry labelled the 2000 rat study and the 2001 mouse study as clinical trials and called AOD-9604 GRAS as a cosmetic ingredient; both are corrected here. Grey Peptides sells nothing and links to no vendor.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Talk to a licensed clinician about your own situation.