AOD-9604 for Women: Why the "Fat-Loss Peptide" Failed Its Obesity Trials
AOD-9604 had what most "fat-loss peptides" never get: real human trials. That's exactly why we know it didn't work for weight loss. Here is the history, what the safety data show, and where it stands in 2026.
AOD-9604 was developed as an obesity drug, tested in randomized human trials, and dropped when a phase 2b trial in 536 people over 24 weeks failed to produce significant weight loss compared with placebo. Its development for obesity ended in 2007. The safety data from those trials looked clean, which is the part marketers tend to quote, but "safe in trials" and "works" are different questions, and on the second one the answer from its own developer's trials was no. It is not FDA-approved, and in 2026 it doesn't appear in any of FDA's categories for 503A compounding.
What AOD-9604 is
AOD-9604 is a modified fragment from the tail end (C-terminus) of human growth hormone. Growth hormone promotes fat breakdown, but it also raises blood sugar and stimulates growth through IGF-1. The idea behind AOD-9604 was to keep the fat-burning signal and drop the rest. Our AOD-9604 profile covers the proposed mechanism.
The animal data that started it
The early promise came from mice. A 2001 study in Endocrinology (Heffernan et al.) reported that AOD9604 reduced body weight and body fat in obese mice after 14 days of daily injections into the abdominal cavity. In mice lacking the beta-3 adrenergic receptor, the chronic weight effect disappeared, which pointed to how it might work.
Mouse obesity results often fail to carry over to people. Mice have different fat biology, the doses and routes don't match human use, and 14 days is very short.
The human trials
Safety: clean
A 2013 paper, Stier, Vos and Kenley in the Journal of Endocrinology and Metabolism, pooled six randomized, double-blind, placebo-controlled trials. They reported that AOD9604 "displayed a very good safety and tolerability profile indistinguishable from placebo," with no withdrawals or serious adverse events attributed to it, unchanged IGF-1 levels, no worsening of glucose tolerance and no antibodies detected. The abstract does not report weight-loss results.
Efficacy: the trial that ended the program
The decisive study was a phase 2b obesity trial run by Metabolic Pharmaceuticals. According to the Superpower evidence guide, which cites a 2013 review in Current Cardiology Reviews (Misra, PubMed 23092275), the trial enrolled 536 people for 24 weeks and did not produce significant weight loss versus placebo, and development for obesity was terminated in 2007.
That's the core of the story. AOD-9604 got a fair test in people, at the scale drug developers use to decide whether to continue, and its own developer stopped. We weren't able to retrieve the original trial report, so we're relying on these summaries for the specific figures.
Why "safe" became the selling point
After the obesity program ended, AOD-9604 found a second life in clinics and research-chemical shops. The safety paper became the most-cited reference in marketing, often alongside the mouse data. What usually goes unmentioned is the efficacy trial in between. When a product's promotion relies on animal results and safety data, but skips the human efficacy trial, that gap is the most important thing on the page.
Why women are the target audience
AOD-9604 is often marketed for "stubborn" fat, menopause weight gain and belly fat, all concerns that skew female. Midlife changes in fat distribution are real; see menopause belly fat. But nothing in AOD-9604's trial record shows it addresses them. We found no trials of AOD-9604 designed around perimenopausal or postmenopausal women.
Myths vs evidence
| Claim | What the evidence shows |
|---|---|
| "Clinically proven fat loss." | The phase 2b obesity trial didn't show significant weight loss vs placebo; obesity development ended in 2007. |
| "Burns fat without the side effects of growth hormone." | The safety trials found no IGF-1 or glucose effects. That supports the "no side effects" half, not the "burns fat" half in humans. |
| "FDA-approved" or "FDA-recognized." | Not FDA-approved for any use. |
| "Back on the compounding list in 2026." | Its nomination was withdrawn and it was removed from Category 2 in 2024; FDA's May 2026 categories document doesn't list it at all. That isn't approval or inclusion on the 503A ingredients list. |
| "Great for menopause belly fat." | No trials in menopausal women; the general obesity trial was negative. |
Regulatory status in 2026
- FDA approval: none.
- Compounding: AOD-9604 had been in FDA's Category 2. Its nomination was withdrawn and it was removed from Category 2 effective September 27, 2024 (Reed Smith), and it appeared on the December 4, 2024 advisory committee agenda (A4PC). FDA's 503A categories document updated May 14, 2026 does not list it in any category (FDA), and it isn't among the peptides scheduled for 2026–2027 advisory committee review (FDA Law Blog).
- Sport: evidence summaries note it is prohibited by the World Anti-Doping Agency.
For the wider 2026 regulatory picture, see our FDA peptide reclassification explainer. There is no approved human dose, and research-use-only peptides are not sold for human use.
What has evidence for weight loss in women
If your goal is meaningful weight loss and you meet the medical criteria, FDA-approved medications have the trial evidence AOD-9604 lacks. In SURMOUNT-1, tirzepatide produced roughly 15% to 21% average weight loss over 72 weeks versus 3.1% on placebo, and a Lilly pooled analysis suggests women lost more than men (see our SURMOUNT breakdown by sex). Semaglutide has its own large trial program. These drugs have real side effects and costs, but they have shown they work.
For abdominal fat specifically, tesamorelin is FDA-approved for a narrow indication (excess abdominal fat in people with HIV-associated lipodystrophy), which makes for a useful contrast with AOD-9604; see our tesamorelin vs AOD-9604 comparison.
Questions to ask anyone selling AOD-9604
- Which human trial shows it causes weight loss? (Ask for the citation, not a mouse study or a safety paper.)
- Why did the developer stop the obesity program?
- Under what legal pathway is this product compounded or sold for human use?
- Who manufactured it, and can you show third-party testing for identity, purity and sterility?
- What approved options did you consider for me first, and why not those?
Prescription Option (Telehealth)
If you're considering weight-loss medication, start with the options that have human trial evidence behind them.
Sesame Care offers telehealth weight-care visits with licensed clinicians. The clinician reviews your history and decides whether a medication is appropriate.
The lesson for judging any "fat-loss peptide"
AOD-9604's history is a handy template for reading claims about other compounds:
- Where's the human efficacy trial? Animal fat-loss results are common; human ones are rare. If none exists, the claim is a hypothesis.
- Was it randomized and placebo-controlled? Weight changes for many reasons, including simply joining a program. Only a placebo group shows what the compound added.
- What happened next? A developer that stops a program after a large trial is telling you something.
- Is safety being used in place of efficacy? "Well tolerated" answers a different question than "works."
Our peptide evidence ladder walks through these levels in more detail.
The bottom line
AOD-9604 is a rare case where a marketed "fat-loss peptide" actually went through serious human testing, and the testing didn't support it. It appeared safe in trials, which is worth knowing, but the reason anyone would take it, weight loss, wasn't demonstrated in people. Our weight management hub sorts the options that do have evidence.
Sources
- 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):5182-5189.
- Stier H, Vos E, Kenley D. Safety and Tolerability of the Hexadecapeptide AOD9604 in Humans. J Endocrinol Metab. 2013;3(1-2):7-15.
- Superpower. AOD-9604 evidence guide (summarizing the phase 2b trial; cites Misra, Curr Cardiol Rev 2013).
- Reed Smith. FDA removes certain peptide bulk drug substances from Category 2.
- U.S. Food and Drug Administration. Bulk Drug Substances Nominated for Use in Compounding Under Section 503A. Updated May 14, 2026.
- FDA Law Blog. FDA's Pep(tide) Rally! April 21, 2026.
- Jastreboff AM, et al. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med. 2022.