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PeptideLimited humanNot FDA approved

AOD-9604

AOD-9604

Last reviewed October 27, 2026 · 16 sources · Written for general readers · Compare with another compound →

The bottom line

AOD-9604 was tested in several hundred people as a weight loss pill, and its largest trial did not beat placebo, so the maker stopped. FDA staff found no evidence it works for obesity and too little data to judge its safety. It is not approved, has never been tested as the shots sold online, and is banned in sport.

Where the evidence stands

What it is

AOD-9604 is a lab made peptide based on one small piece of human growth hormone, with one extra amino acid added.[1] A company called Metabolic Pharmaceuticals developed it in the late 1990s as a fat loss drug.[1]

After its obesity trials failed, the developer announced in 2014 that it had GRAS status in the US (generally recognized as safe) for use as a food or supplement ingredient. The report did not say FDA had reviewed it.[2]

FDA notes that sources do not agree on its CAS number, and some nominated products did not match their paperwork.[1]

Name
AOD-9604 (AOD-9604)
Other names
AOD9604, hGH fragment 177-191 with added tyrosine
Type
Peptide
Sequence
YLRIVQCRSVEGSCGF
CAS number
221231-10-3
Formula
C78H123N23O23S2
Molecular weight
About 1815.1 g/mol

What it does in the body

AOD-9604 is a copy of the tail end of human growth hormone (the last 15 building blocks) with a tyrosine added at the front. It does not occur on its own in the body. In lab tests it does not bind the growth hormone receptor, and FDA says its real target is unknown.[1][4]

This is the biology, area by area. A change measured in the body, like a higher blood level, does not always mean a person feels a benefit. The claims check below covers that.

Fat tissue

Seen in animals

In obese mice treated for 14 days, it slowed weight gain, raised fat burning and raised glycerol in the blood, a sign that fat was being broken down.[4] Obese rats given it by mouth for about three weeks gained less than half as much weight as untreated rats.[5]

Fat and weight in people

Measured in people

Human trials of pills and vein infusions found little or no weight loss beyond placebo, including the largest trial of 502 people over 24 weeks.[1] One small 4 week pill study saw a blood marker of fat breakdown rise, even though weight did not change.[1] So a fat cell signal may show up in blood tests without real weight loss.

Hormones

Measured in people

A company funded review of six small placebo controlled trials reported no change in IGF-1, the main growth hormone marker in blood, and no antibodies against the drug.[6] In mice and cells, it did not act like growth hormone on its receptor or on cell growth.[4]

Blood sugar

Measured in people

In obese rats, a clamp test found no harm to insulin sensitivity, unlike intact growth hormone.[5] In obese mice it did not cause high blood sugar.[4] In people, only a company funded review of small trials reported no harm to blood sugar handling.[6]

Joints and cartilage

Seen in animals

In 32 rabbits with damaged knees, shots into the joint lowered cartilage damage scores compared with salt water. Combining it with hyaluronic acid, a joint lubricant, worked better than either alone and sped recovery from limping.[7] No human joint study has been done.[1]

Bones

Seen in animals

Six month safety studies in rats found changes in bone markers, and FDA judged the animal safety data too limited to draw conclusions.[1]

How it works

The idea was to keep growth hormone's fat burning effect without its effects on growth or blood sugar.[1]

  • In obese mice, it raised markers of fat breakdown and fat burning without causing high blood sugar or lowering insulin release.[3][4]
  • In mice missing the beta 3 receptor, a switch on fat cells, long term treatment did not cause weight loss, yet a short test still raised fat burning. The authors concluded the receptor is not its direct target.[3]
  • In cell tests, it did not bind the growth hormone receptor or trigger cell growth the way growth hormone does.[1][4]
  • FDA says its actual target in the body is still unknown.[1]

Mechanism ideas come from small animal and cell studies and remain uncertain.

What the research shows

We keep animal and human evidence apart. A result in animals is a reason to study something in people, not proof that it works in people.

Animal and lab studies

Modest effects in obese mice and rats

  • Obese mice treated for 14 days gained about 5% to 10% less weight and had smaller fat pads, with no change in blood sugar or insulin.[3][1]
  • In a second 14 day mouse study, it raised fat burning and fat breakdown without causing high blood sugar, and it did not bind the growth hormone receptor.[4]
  • Obese rats given it by mouth for about three weeks gained less than half as much weight as untreated rats, without the insulin resistance growth hormone causes.[5][1]
  • In 32 rabbits with knee arthritis, shots into the joint reduced cartilage damage, and the effect was larger when combined with hyaluronic acid.[7]
  • Safety studies found bone marker changes in rats over six months and liver cell changes in monkeys over nine months.[1] The company's own report of these studies described no toxic effects.[8]
  • FDA judged tests for DNA damage unclear and found no cancer or reproduction studies, while a company paper reported that its DNA tests were negative.[1][8]

Limit: FDA found the animal safety data too limited to judge the risk, and most animal work came from the developer.

Human studies

Tested in several hundred people, and the big trial failed

  • A placebo controlled study gave the drug by vein once a week to 23 adults with severe obesity. Weight loss over 3 weeks averaged about half a kilogram and was not different from placebo.[1]
  • A small pill study in 16 men with obesity over 4 weeks found no weight loss beyond placebo, though a blood marker of fat breakdown rose.[1]
  • A one week pill study in 36 men with obesity found about 1 kilogram of loss at one dose versus 0.6 on placebo, with other doses doing worse.[1]
  • A 12 week trial of 300 people taking daily pills reported smaller waists, but weekly weight differences of only about a tenth of a kilogram versus placebo. It was reported only as a meeting abstract.[1]
  • The largest trial randomized 502 people to daily pills or placebo for 24 weeks. It missed its main goal, and the company ended obesity development in 2007. Results were never published in a journal.[1]
  • A company funded review of six trials reported side effects similar to placebo, no change in IGF-1 and no antibodies against the drug.[6]
  • In one small vein infusion safety study of 15 men, headache, tiredness and dizziness were the most common complaints, spread evenly across drug and placebo. In another, one case of severe chest tightness was judged possibly related.[1]
  • FDA staff concluded in 2024 that AOD-9604 showed no evidence of effectiveness for obesity, and found no human data at all for shots under the skin or creams.[1]

Limit: Most human data come from the maker and were never fully published, so FDA had to rely on summaries and company announcements.

Claims check

The most common claims about this compound, and what studies actually found. Verdicts rate the evidence, not whether you should use it.

Burns body fat and causes weight loss

No benefit in trials so far

The largest trial gave 502 adults with obesity a daily pill or placebo for 24 weeks, along with diet and exercise, and found no meaningful difference in weight loss. An earlier 12 week trial in 300 people found only tiny differences, and a vein infusion study in 23 adults found no difference from placebo.[1] FDA staff concluded in 2024 that there is no evidence it works for obesity by any route.[1]

Gives growth hormone's fat loss without its side effects

Mixed results

A company funded review of six small placebo controlled trials reported no change in IGF-1 (a growth hormone marker) and no harm to blood sugar handling.[6] But FDA notes the authors worked for or advised the maker and key details were missing, and the drug also showed no real fat loss benefit in people.[1]

Safe, with side effects like placebo

Mixed results

The company review of six trials reported no serious side effects tied to the drug and found no antibodies against it.[6] Company animal studies in rats and monkeys reported no toxic or DNA damaging effects.[8] But FDA says it lacks enough information to know whether AOD-9604 harms people, and has identified serious adverse events that may be linked to it.[9]

Repairs cartilage and joints

Only in animals

A study in 32 rabbits with knee arthritis found less cartilage damage after shots into the joint, especially when combined with hyaluronic acid.[7] FDA found no registered human studies of AOD-9604 for any use, including joints.[1]

Works as a shot under the skin or a cream

Not tested

FDA found no human or animal studies at all of AOD-9604 given as a shot under the skin or applied to the skin, which are the forms most often sold online. Human trials used pills or vein infusions.[1]

Builds muscle or slows aging

Not tested

FDA's full review of the evidence lists studies on fat, cartilage, bone and safety only, with no study of muscle growth or aging in people or animals.[1]

Known risks and side effects

  • Immune reactions. FDA says injected AOD-9604 may trigger the immune system, partly because impurities in peptide products are hard to control.[9]
  • Possible serious side effects. FDA has identified serious adverse events that may be linked to AOD-9604, though it is unclear whether the drug caused them.[9]
  • Side effects seen in trials. Small trials reported headache, tiredness, dizziness and low blood sugar episodes, at similar rates on drug and placebo, plus one case of severe chest tightness possibly tied to the drug.[1]
  • Unregulated products. FDA found nominated products were poorly characterized, with no limits set for clumping and a bacterial toxin test shown on only one supplier certificate. The forms sold online have never been tested in people.[1] Belgian authorities have seized unlabeled medicine preparations that a lab later identified as AOD-9604.[10]
  • Banned in sport. WADA names AOD-9604 directly as a banned growth hormone fragment on its 2026 and 2027 lists.[11][12] It does not interfere with WADA's standard growth hormone test, and researchers have published separate methods to detect it.[13][14]

Regulatory status

Today: AOD-9604 is not approved by FDA. FDA staff advised in 2024 against adding it to the list of substances pharmacies may use for compounding.[15] By April 2026, FDA listed it among substances whose compounding nominations were withdrawn, while still listing its safety risks.[9] It remains banned in sport for 2027.[12]

  1. Developer says its phase 2b results did not support further obesity development.[1]
  2. The developer announced a US GRAS designation for use in foods and supplements. The report did not say FDA had reviewed it.[2]
  3. FDA briefing document recommends against adding AOD-9604 to the compounding list.[1][15]
  4. AOD-9604 is on the agenda of FDA's Pharmacy Compounding Advisory Committee meeting.[16]
  5. WADA 2026 Prohibited List takes effect, naming AOD-9604 as banned.[11]
  6. FDA's safety risk page lists AOD-9604 as nominated but withdrawn.[9]
  7. WADA published its 2027 list, which again names AOD-9604 as a banned growth hormone fragment.[12]

Sources

  1. U.S. Food and Drug Administration. FDA Briefing Document: AOD-9604 related bulk drug substances. Pharmacy Compounding Advisory Committee meeting, December 4, 2024. FDA briefing document
  2. Lab+Life Scientist. AOD9604 awarded safe status in US. August 2014. News report
  3. Heffernan M, Summers RJ, Thorburn A, et al. The Effects of Human GH and Its Lipolytic Fragment (AOD9604) on Lipid Metabolism Following Chronic Treatment in Obese Mice and β3-AR Knock-Out Mice. Endocrinology. 2001;142(12):5182-5189. doi 10.1210/endo.142.12.8522
  4. Heffernan M, Thorburn A, Fam B, 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;25:1442-1449. PMID 11673763
  5. Ng FM, Sun J, Sharma L, et al. Metabolic Studies of a Synthetic Lipolytic Domain (AOD9604) of Human Growth Hormone. Horm Res. 2000;53(6):274-278. doi 10.1159/000053183
  6. Stier H, Vos E, Kenley D. Safety and Tolerability of the Hexadecapeptide AOD9604 in Humans. J Endocrinol Metab. 2013;3(1-2):7-15. doi 10.4021/jem157w
  7. Kwon DR, Park GY. Effect of Intra-articular Injection of AOD9604 with or without Hyaluronic Acid in Rabbit Osteoarthritis Model. Ann Clin Lab Sci. 2015;45(4):426-432. PMID 26275694
  8. Moré MI, Kenley D. Safety and Metabolism of AOD9604, a Novel Nutraceutical Ingredient for Improved Metabolic Health. J Endocrinol Metab. 2014;4(3):64-77. doi 10.14740/jem213w
  9. U.S. Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks. Content current as of April 22, 2026. FDA Category 2 list
  10. Vanhee C, Moens G, Deconinck E, De Beer JO. 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):964-968. PMID 24976118
  11. World Anti-Doping Agency. World Anti-Doping Code International Standard: Prohibited List 2026. Effective January 1, 2026. WADA 2026 Prohibited List
  12. World Anti-Doping Agency. World Anti-Doping Code International Standard: Prohibited List 2027. Effective January 1, 2027. WADA 2027 List
  13. Orlovius AK, Thomas A, Schänzer W, et al. AOD-9604 does not influence the WADA hGH isoform immunoassay. Drug Test Anal. 2013;5(11-12):850-852. PMID 24124033
  14. Cox HD, Smeal SJ, Hughes CM, Cox JE, Eichner D. Detection and in vitro metabolism of AOD9604. Drug Test Anal. 2015;7(1):31-38. PMID 25208511
  15. U.S. Food and Drug Administration. Draft questions for the Pharmacy Compounding Advisory Committee, December 4, 2024. FDA draft questions
  16. U.S. Food and Drug Administration. December 4, 2024 Meeting of the Pharmacy Compounding Advisory Committee. FDA meeting page
Medical disclaimer

This page is educational information only. It is not medical advice and does not replace care from a licensed medical provider. Do not use this page to decide whether to take any substance. Talk to a licensed medical provider first.

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