Study teardown · AOD-9604 (AOD9604, hGH fragment 176-191, sold online and by clinics for fat loss) · 25 years of records from the 1990s obesity program to 2026: rodent studies, six developer-funded human trials, the 2007 phase 2b result, the GRAS food-ingredient route, FDA’s 2024 review, recalls, WADA status, registry, FAERS and PubMed counts · Sources checked October 25, 2026

Published October 25, 2026 · Updated October 25, 2026

AOD-9604: does the “fat-loss fragment” of growth hormone work, and is it safe? Its developer tested it as an obesity pill in six trials of about 890 people, the largest missed its weight-loss goal and the program was ended in 2007, nobody has published a human trial of the injection sold today, and FDA’s advisers voted 12-0 against allowing it in compounding.

AOD-9604 is a short, modified piece of human growth hormone: the hormone’s last 15 amino acids with one extra amino acid added at the front.[16] An Australian company, Metabolic Pharmaceuticals, developed it in the late 1990s as an obesity drug, on the idea that this end of growth hormone carries its fat-burning effect without its effects on blood sugar and growth.[1][14][12] It cut weight gain in obese rats and mice.[11][12] In people, the company ran six placebo-controlled trials in about 890 adults, mostly with oral doses, and in February 2007 it announced that its phase 2b trial did not support the drug’s commercial viability and that the obesity program was terminated.[9][5] Today AOD-9604 is mainly sold as an injection, yet FDA found no human data at all for injection under the skin, and in December 2024 FDA’s compounding advisers voted 12-0 against allowing it.[1][2] The honest answer: there is no good evidence that it helps people lose fat, and its safety as sold today is largely untested.[1][3]

Why this matters now

AOD-9604 is promoted online and by some wellness clinics and medical spas as a “fat-loss peptide,” and FDA’s 2024 review found it marketed for uses from weight loss and metabolism to cartilage, osteoarthritis and anti-aging.[1] Three of the five bulk-powder listings for AOD-9604 in FDA’s drug directory have 2026 marketing start dates, which shows raw material is being registered, not that any product is approved.[26] Two 2026 medical reviews group it with other unapproved peptides, and one warns that rigorous human safety data for such peptides are scarce.[19][20] And FDA’s interim peptide compounding policy has been under White House review since October 14, 2026, with its peptide list not public.[22] For where every peptide stands, see our FDA peptide compounding status tracker.

Timeline

What AOD-9604 is

The name stands for “anti-obesity drug” 9604.[19] It is 16 amino acids long: growth hormone’s amino acids 177 to 191 plus an added tyrosine, which is why it is also sold as “hGH fragment 176-191.”[16][20] In obese mice it did not compete for the growth hormone receptor, did not make cells multiply and did not raise blood sugar, unlike growth hormone itself.[12] In the developer’s human trials, it did not raise IGF-1, the main growth hormone signal in blood.[9] How it works is unclear: one mouse study linked its weight effect to the beta-3 adrenergic receptor, though the authors concluded its action is not mediated directly through that receptor, and FDA’s 2024 review says the molecular target and mechanism “remain unknown.”[13][1] It also breaks down fast: in pigs its half-life was about 3 minutes, and FDA noted that the developer’s oral absorption estimate of 170% “unrealistically exceeds the theoretical maximal 100%.”[1][10] FDA found no human studies of how the body handles it by any route.[1]

The evidence, rung by rung

• Animals. In obese Zucker rats, oral AOD-9604 for 19 days cut body-weight gain by more than half versus controls, and in obese mice 14 days of treatment reduced weight gain and raised fat burning.[11][12] FDA cautioned that these studies did not test dose-response for weight loss and that their statistics were not corrected for multiple comparisons.[1]
• Small human trials. Four early trials in groups of 15 to 36 men used single IV or oral doses or courses of up to a few weeks. They were mainly safety and dosing studies, and where weight was reported it did not differ significantly from placebo, according to FDA’s summary of the published record.[1][14]
• The 12-week trial. A 300-person oral trial was reported only in a 2005 meeting abstract, which said weight loss was greater than placebo at all doses and “significant” for women at one dose. FDA noted that the details were not provided.[1]
• The phase 2b trial. The largest study (called OPTIONS) enrolled 536 adults with obesity and randomized 502 to one of three daily oral doses or placebo for 24 weeks, alongside a supervised diet and exercise program. It was powered to detect 1.8 kg of extra weight loss. Weight loss versus placebo was “less than 1 kg in all dose groups” and not statistically significant, and the company ended the program.[1][5]
• Other uses. The cartilage and osteoarthritis claims rest on a study of knee injections in 32 rabbits.[15] We found no human trial of AOD-9604 for joints, skin, cholesterol or aging, and ClinicalTrials.gov has no AOD-9604 records.[23][27]

The human trials, in one chart

All six trials were funded by the developer, and the paper pooling their safety data was written by its employees or consultants, as FDA notes.[9][1] FDA matched the 2005 abstract and the 2007 phase 2b announcement to two of these six trials, so they are not extra studies.[1] The company itself pointed to a prespecified subgroup that did lose weight and suggested that the strong diet-and-exercise effect in the placebo group may have masked the drug; the overall result was still negative.[5]

From obesity drug to “food ingredient”

After the obesity program ended, the developer took a different route. In 2012 its parent company announced a “self-affirmed conditional GRAS status,” a determination by an expert panel it contracted, saying it would allow AOD-9604 to be added to foods, drinks and dietary supplements in the US once its safety data were published.[6] The two safety papers appeared in 2013 and 2014, and in July 2014 the company announced “full” GRAS status; the same announcement said it had licensed AOD-9604 to two Australian compounding pharmacies.[9][10][7] Our analysis: telling FDA about a GRAS determination is voluntary, and FDA’s public GRAS notice inventory lists no notice for AOD-9604, so this was the company’s own conclusion rather than an FDA finding.[8] GRAS also concerns use in food; it says nothing about injecting a substance, and FDA’s 2024 review evaluated AOD-9604 as a drug ingredient for compounding.[8][1]

Safety

• What the trials reported. The developer described safety and tolerability as indistinguishable from placebo, with no antibodies against the peptide detected in the samples tested.[9][5] FDA’s review of the same record lists serious adverse events in oral trials, including diarrhea, chest tightness and several cancers (basal cell and squamous cell skin cancers, breast cancer and melanoma in the 12-week trial), which the investigator judged unrelated; FDA said there was not enough information to assess whether they were related.[1] In an IV study, severe chest tightness and euphoria were judged possibly related.[1]
• Long-term use. FDA concluded there is “insufficient information to support patient safety for the long-term use” of AOD-9604 in obesity, a condition that may need long-term treatment.[1]
• Animal signals. FDA flagged changes in a bone hormone (osteocalcin) in rats as “a clinically relevant nonclinical safety signal,” and a liver finding seen in all high-dose female monkeys after 9 months as a possible signal of liver injury.[1] The developer’s paper reported no genotoxicity, while FDA described the bacterial mutation test results as “equivocal” and noted the paper gives no data tables.[10][1]
• Injection under the skin. FDA found no human data and no repeat-dose animal toxicity studies for this route.[1]
• Quality. FDA says the substance is “not well characterized,” that endotoxin testing for injectable forms is lacking, and that there is no USP monograph; its safety-risk page flags immune-reaction and impurity risks and serious adverse events “though causality is not clear.”[1][3] Two compounded injectables were recalled in 2020 and 2021 for lack of assurance of sterility.[25]
• Reports. FAERS holds no AOD-9604 reports, which FDA itself says “does not imply that the substance is safe.”[24]

Legal status

No AOD-9604 drug is approved by FDA.[24] In 2024, FDA proposed not adding it to the 503A bulks list, the list that would let pharmacies compound it, and the advisory committee agreed 12-0 without discussion.[1][2] The nomination is now listed by FDA as withdrawn, AOD-9604 does not appear on FDA’s May 2026 list of nominated substances, and FDA’s page of compounding substances that may present significant safety risks includes it.[3][4] FDA’s pending interim peptide policy could change how some peptides are handled, but its list is not public.[22] Five bulk-powder listings exist in FDA’s NDC directory, and a listing is not approval.[26] FDA’s briefing also notes that Australia’s medicines scheduling committee added AOD-9604 to its poisons standard among performance and image enhancing drugs.[1] In sport, WADA bans “growth hormone fragments, e.g. AOD-9604 and hGH 176-191” at all times.[21]

What a careful reader should notice

These points are our analysis of the sources cited.

1. The fat-loss claim comes from rodents. In the human trials, the largest and longest one missed its weight-loss goal, and the developer itself called the program commercially unviable.[11][12][5]
2. Almost all human data are for oral doses. The injection sold today has no published human trial, so even the reassuring safety summary does not describe how it is used now.[1][9]
3. The main human safety paper and the GRAS determination came from the developer and a panel it hired, and FDA has not reviewed a GRAS notice for it. That does not make them wrong, but it is not independent confirmation.[9][6][8]
4. “Not growth hormone” is supported for the growth hormone receptor, IGF-1 and blood sugar in the studies cited, but what it does act on is still unknown.[12][9][1]
5. “Banned in sport” and “safe” are separate questions; the ban reflects its classification as a growth hormone fragment, not proof that it works.[21][16]

Frequently asked questions

Does AOD-9604 work for fat loss?

Not in the human trials that have been reported. It reduced weight gain in obese rats and mice, but in people the developer’s largest trial, with 502 adults over 24 weeks, found weight loss versus placebo of less than 1 kg and not statistically significant, and the obesity program was ended in 2007.[11][12][5][1]

Is AOD-9604 safe?

Its long-term safety is unknown. Short oral trials funded by the developer reported placebo-like tolerability, but FDA found no human data for injection under the skin, flagged animal safety signals and quality concerns, and concluded there is not enough information to support long-term safety.[9][1][3]

Is AOD-9604 FDA approved?

No. There is no approved AOD-9604 product, FDA recommended against allowing it in pharmacy compounding, and its advisers voted 12-0 against.[24][1][2]

Does AOD-9604 have GRAS status?

Its developer announced a self-affirmed GRAS determination for food and supplement use in 2012 and 2014, made by an expert panel it contracted. FDA’s GRAS notice inventory lists no notice for AOD-9604, and GRAS concerns food use, not injections.[6][7][8]

Is AOD-9604 the same as HGH fragment 176-191?

They are used as names for the same peptide: growth hormone’s amino acids 177-191 with an added tyrosine. WADA’s list names both.[16][21]

Does AOD-9604 raise IGF-1 or blood sugar like growth hormone?

In the studies reported, no: it did not bind the growth hormone receptor or raise blood sugar in mice, and the developer reported no effect on IGF-1 in its human trials.[12][9]

Is AOD-9604 banned in sport?

Yes. WADA’s 2026 Prohibited List names AOD-9604 as a growth hormone fragment, prohibited at all times.[21]

Bottom line

AOD-9604 began as a serious drug program, and its developer tested it in about 890 people before concluding in 2007 that the results did not support it as an obesity treatment.[9][5] The food-ingredient GRAS status that followed was the company’s own determination, not an FDA review.[6][8] The injection sold today has no published human trial, FDA flags it as a compounding safety risk, its advisers voted 12-0 against it, and it is banned in sport.[1][2][3][21] People who want medical help with weight have FDA-approved options with large trials behind them to discuss with a doctor; see our teardowns of semaglutide’s STEP 1 trial and tirzepatide’s SURMOUNT-1 trial.

This page analyzes published studies, regulator documents, company announcements and registry data. It is not medical or legal advice and does not recommend any product or dose. AOD-9604 is not approved by FDA. Charts were rebuilt by Jabbit from the sources cited in each caption.