AOD-9604 already had its large trial. It missed, and the program was shut down.

The vote nobody covered

When FDA’s Pharmacy Compounding Advisory Committee narrowly backed BPC-157 in July 2026, the coverage treated the peptide-compounding question as newly open. It was not new. On December 4, 2024, the same committee worked through three peptides that circulate in the same market: AOD-9604, CJC-1295 , and Thymosin Alpha-1 .[3]

On AOD-9604 the committee first agreed, 12 to 0, to take a single vote covering both the free base and the acetate. Then it voted on whether the two substances should be placed on the 503A Bulks List. The result was 0 yes, 12 no, no abstentions. The minutes record no committee discussion on that question.[2]

AOD-9604 was not among the six peptides reconsidered at the July 2026 meeting, so the 2024 vote stands as the committee’s most recent word on it.[10] AOD-9604 is not an FDA-approved drug for any use.[13]

Evidence ledger

The entire human record FDA found

FDA searched PubMed, Embase, ClinicalTrials.gov, DailyMed, Drugs@FDA and other sources. It found five human studies, and noted that a search of ClinicalTrials.gov returned no registered studies of AOD-9604 at all.[1] The counts below describe separate studies over more than a decade, not one program.

Study sizes as reported in FDA’s 2024 evaluation. The three small studies come from a single 2004 review of the developer’s program.[1]

Reviewing the first three, the author of that 2004 summary wrote that the clinical studies did not show any statistically significant weight loss when AOD-9604 was given to patients with obesity compared with placebo. FDA added that the publication gave insufficient detail on methodology and results to appraise them properly.[1]

The trial that was built to settle it

The OPTIONS study was the real test. It was randomized, double-blind and placebo-controlled, with 536 adults with obesity enrolled and 502 randomized, aged 18 to 65 with a BMI of 30 to 45. Participants took oral AOD-9604 at 0.25, 0.5 or 1 mg once daily, or placebo, alongside a dietician-supervised diet and exercise program, for 24 weeks. The primary endpoint was statistically significant weight loss at 12 weeks for any of the three doses. By the sponsor’s account the trial was powered for an 80% chance of hitting that endpoint if the difference from placebo reached 1.8 kg.[1]

It missed. FDA’s summary of the trial data is that there was not a significant difference in the primary endpoint of weight loss between placebo and AOD-9604. The sponsor stated that weight loss compared with placebo at 12 and 24 weeks was too low to reach statistical significance, that the trial had been run under what it called Phase 3 conditions, and that development of the drug for obesity was terminated.[1]

FDA could not find the study published in the medical literature. That is a real limitation and it cuts both ways: the negative result, like the positive abstract before it, has never been through peer review. What can be said is that the largest and longest human trial of AOD-9604 did not show a weight-loss benefit, and the company that ran it stopped.

The study usually cited as the positive one

Vendor and clinic pages that cite any trial at all usually reach for a 12-week study in 300 adults with obesity. It deserves a fair hearing. Participants were randomized after a two-week run-in to oral AOD-9604 at 1, 5, 10, 20 or 30 mg per day or placebo. The authors reported that weight loss over 12 weeks was greater at all doses than placebo, with a non-linear dose response, that the largest effect was at 1 mg, and that it was “significant” for females.[1]

The reported numbers are the reason for caution. Mean weekly weight loss was 0.22 kg per week at 1 mg, 0.13 kg at 20 mg and 0.15 kg at 30 mg, against 0.07 kg per week on placebo. No figures were given for the 5 mg and 10 mg groups. FDA’s assessment was that the claim of weight reduction rests on small differences between treatment and placebo groups whose meaningful therapeutic effect is unclear, and that interpretation is limited by the minimal data in the abstract. FDA did not locate a publication of the study’s methods and results.[1]

So the strongest positive human signal for AOD-9604 is a conference abstract, at a dose of about 1 mg a day, reported without full methods — and the larger, longer trial that followed it, testing that same 1 mg dose, did not reproduce the effect.

The route gap

Nobody studied the way it is actually sold

This is the finding most relevant to anyone looking at a vial. The nominations asked FDA to consider oral, subcutaneous and transdermal use. FDA’s response was direct: the nominations did not include, and the agency did not identify, human exposure data for the subcutaneous or topical routes.[1] Every human study above used oral or intravenous administration.

The research market sells something else. Across pepmg’s index, generated August 5, 2026, AOD-9604 appears in 116 listings from 80 vendors, overwhelmingly as lyophilized vials for reconstitution — 5 mg is by far the most common size, followed by 10 mg.[14] The oral trials that failed used 0.25 to 1 mg per day.

A 5 mg injectable vial is not a smaller or larger version of the thing that was tested; it is a different route with no human exposure data behind it. FDA separately noted that endotoxin testing for the injectable route was lacking in what it reviewed, and that it found no pharmacokinetic or bioavailability information for AOD-9604 in humans by any route.[1]

The animal data is real, and it is animal data

The mechanism story behind AOD-9604 comes almost entirely from rodents, and it is worth stating plainly that none of the work in this section was done in people. In obese Zucker rats given AOD-9604 by oral gavage for 21 days, treated animals gained roughly 50% less body weight than vehicle controls and showed higher lipolytic activity in adipose tissue, without the insulin resistance seen with growth hormone.[6] In obese mice treated for 14 days, body-weight gain was about 5 to 10% lower than in controls, with increased fat oxidation.[7] An earlier study reported effects after oral administration in rodents.[8]

The same mouse work also found that the effect depended on intact β3-adrenergic receptor signalling: in mice lacking that receptor, AOD-9604 had no effect on body-weight gain, fat-pad size or plasma glycerol.[7] That is a genuinely interesting mechanistic result. It is also a result in knockout mice.

FDA’s own reading of this literature was cautious. It noted that none of the studies assessed dose-response relationships for body-weight loss, that the statistics were not corrected for multiple comparisons, and that the molecular targets of AOD-9604 have not been identified and its mechanism of action remains unknown, which makes the biological plausibility of the reported effects hard to assess.[1]

What FDA said about safety

The safety picture is thin rather than alarming, and the distinction matters. In nonclinical work, FDA described signals suggestive of negative effects on bone health in rats given the peptide orally for 13 weeks, signals potentially indicative of liver toxicity in cynomolgus monkeys dosed orally for nine months, and equivocal mutagenic signals in in-vitro and in-vivo genotoxicity assays. It concluded that nonclinical studies were too limited in scope to inform safety for the nominated oral, subcutaneous and transdermal routes.[1]

On the human side, FDA listed serious adverse events reported in oral studies including diarrhea, chest tightness and various types of cancers, and in intravenous studies chest tightness and euphoria. FDA stated that causality is not clear, and a handful of events across small studies cannot establish incidence.[4][1] A 2013 paper summarizing the sponsor’s six randomized placebo-controlled trials reported a tolerability profile the authors described as indistinguishable from placebo, with no anti-AOD-9604 antibodies detected in the patients assayed.[5]

FDA’s concern was less about a specific harm than about the size of the record. It flagged that a 16-amino-acid peptide has the potential to be immunogenic, that there is no information to assess immunogenic risk for the subcutaneous and transdermal routes, and that obesity is a chronic condition needing long-term treatment for which no adequate long-term safety information exists.[1] FDA’s page listing bulk substances that may present significant safety risks, current as of April 22, 2026, includes AOD-9604 in its table of substances nominated but withdrawn, citing immunogenicity risk and limited safety information.[4]

Two things this note is not saying

First, a failed trial is not proof that a molecule does nothing. OPTIONS tested three oral doses against placebo on top of a supervised diet and exercise program, and found no detectable separation. That is strong evidence against a clinically useful oral effect at those doses. It is not a demonstration that no effect exists at any dose by any route — that study has not been done.

Second, the December 2024 vote was about compounding eligibility, not about criminality or acute danger. What makes it worth knowing is the reason behind it: FDA’s stated basis was the lack of data on physicochemical characterization, the lack of evidence of effectiveness in obesity, and insufficient safety information.[1] Those three gaps sit underneath every vial sold under this name, whatever the storefront says.

One more practical point for anyone in tested sport: the 2026 Prohibited List names AOD-9604 explicitly under S2.2.3, growth hormone fragments, alongside hGH 176-191.[11][12] Detection methods for it have been published since 2015.[9]

Questions people are asking