AOD-9604: What the Evidence Shows

AOD-9604 does not have evidence that it causes meaningful weight loss in people. Its developer, Metabolic Pharmaceuticals, tested it in six trials. In the largest, 536 adults with obesity took it for 24 weeks, and the weight they lost beyond placebo was under 1 kg at every dose. The company ended the obesity program in February 2007.^[1][5] AOD-9604 has never been approved anywhere.^[5] In December 2024, FDA’s compounding advisers voted 12 to 0 against letting pharmacies compound it.^[3]

What AOD-9604 is

AOD-9604 is a 16-amino-acid piece of human growth hormone: amino acids 177 to 191, the tail end of the hormone, with one extra tyrosine added to make it more stable.^[4] The idea came out of Monash University in Australia. Growth hormone breaks down fat, but long-term use raises blood sugar and has other risks. The hope was that this fragment would keep the fat-burning effect and leave the rest behind.^[4]

In animals it looked promising. In obese Zucker rats, a daily oral dose for 19 days cut weight gain by more than half compared with untreated rats.^[7] In obese mice, it reduced weight gain and raised fat burning. Unlike full growth hormone, it did not raise blood sugar, and it did not bind the growth hormone receptor.^[6] That last finding matters: whatever AOD-9604 does, it does not do it the way growth hormone does. Results in rodents are where many obesity drugs start and stop, though, and this one was then tested in people.

The six human trials, and what each found

Metabolic Pharmaceuticals ran six randomized, placebo-controlled trials between 2001 and 2007, with about 900 adults in total.^[4] (The company’s own later count was 925.^[5]) The first four were small, short safety studies. The last two were built to measure weight loss.

The 2004 trial is the one AOD-9604 marketing still leans on. Every dose group lost more than placebo on average, and in 2006 the company described it as a “very competitive 2kg weight loss more than placebo over a 12 week period.”^[15] The company’s own trial summary is more careful: the best dose, 1 mg, fell short of statistical significance on the main analysis and reached it only in women.^[1] The only public write-up was a conference abstract, which reported weight loss of 0.22 kg a week at 1 mg against 0.07 kg a week on placebo. FDA could find no full publication of the methods or results.^[2]

The OPTIONS trial: the test that settled it

The 2004 results suggested the best dose might be below 1 mg, so the follow-up trial, called OPTIONS, tested 0.25, 0.5 and 1 mg tablets against placebo. It enrolled 536 adults at 16 Australian sites, with a body-mass index of 30 to 45. Everyone went through a supervised diet and exercise program, which is the standard design for obesity drug trials.^[1]

The main goal was a statistically significant weight loss over placebo after 12 weeks at any of the three doses. The trial was designed with enough people to detect a 1.8 kg difference.^[1] The goal was missed. After subtracting the effect of the diet and exercise program, weight loss at both 12 and 24 weeks was less than 1 kg in every dose group.^[1] Safety looked no different from placebo.^[1]

“Metabolic Pharmaceuticals Limited (ASX: MBP) announced today that the Phase 2B trial results for its drug, AOD9604, do not support the commercial viability of the drug as a treatment for obesity. Development of the drug for this condition is terminated.”

— Metabolic Pharmaceuticals, ASX announcement, 21 February 2007

The company offered two explanations. First, people on placebo lost a lot of weight with diet and exercise alone, and the drug’s effect may have been swamped. Second, one subgroup it had planned in advance, women who lost under 2 kg during the diet run-in, showed effects similar to the earlier trial.^[1] Its own conclusion was blunt: AOD-9604 “does not combine or synergise with successful use of an ongoing diet and exercise programme.”^[1] A drug for obesity has to work alongside diet and exercise, because that is how it would be prescribed. When a result shows up only in one subgroup after the main test fails, it is a reason to run another trial, not evidence the drug works. That trial was never run.

OPTIONS was never published in a medical journal, and no AOD-9604 trial is listed on ClinicalTrials.gov.^[2] The developer’s parent company later put it plainly: the trials “did not show a clinically meaningful weight loss outcome across the total trial population.”^[5]

The safety record does not cover how it is sold now

AOD-9604 is often sold as having been “proven safe in humans,” and that claim does have a source. A 2013 paper, two of whose three authors worked for Metabolic Pharmaceuticals, pooled the safety data from the six trials. It found no drug-related serious adverse events or withdrawals, no change in IGF-1 (the hormone growth hormone raises), no harm to blood sugar control, and no antibodies against the peptide in the people tested.^[4]

Those trials gave AOD-9604 as tablets or capsules, or by IV drip in two single-dose studies.^[4] What clinics and online sellers offer now is mostly an injection under the skin. FDA looked for human data on that route and found none.^[2] FDA also noted that serious adverse events in the oral studies included diarrhea, chest tightness and “various types of cancers,” with too little detail to judge whether AOD-9604 caused them.^[2] Its adverse-event database had no reports at all, and FDA warned that this “does not imply that the substance is safe.”^[2]

Two more problems apply to anything bought today. The developer said in 2013 that it “does not manufacture, distribute or sell AOD9604,” so no vial on the market comes from the company that ran the trials.^[5] And FDA has flagged that injected peptides like this one can trigger immune reactions, especially when impurities or clumped peptide are present, and that there is no good public data on AOD-9604’s impurities.^[2][8] Drug-testing labs have found it sold on websites and in vials seized in the US.^[14]

Where AOD-9604 stands with FDA

AOD-9604 is not an FDA-approved drug, and no health authority in the world has approved it.^[5] A pharmacy can compound with an unapproved substance only if it appears on FDA’s 503A bulks list, and that list holds six substances, none of them a peptide.^[10]

• The 2024 review. FDA evaluated AOD-9604 for obesity. It concluded there is “a lack of evidence to support the effectiveness” of the peptide for obesity by any route, and that the balance of evidence “weighs against” adding it to the list.^[2] The people who nominated it had withdrawn their nominations, but FDA brought it to its advisers anyway.^[2]
• The vote. On December 4, 2024, FDA’s Pharmacy Compounding Advisory Committee voted 12 to 0, with no abstentions, against putting AOD-9604 on the list.^[3]
• The safety-risk page. FDA lists AOD-9604 among substances nominated and then withdrawn, with the note that it “has also identified serious adverse events that may be associated with AOD-9604, though causality is not clear.”^[8]
• The interim categories. AOD-9604 is in none of FDA’s three interim categories in the list updated May 14, 2026. That means it does not have the conditional tolerance category 1 substances get.^[9]
• Sport. The World Anti-Doping Agency’s 2026 Prohibited List names AOD-9604 as a banned growth hormone fragment.^[13]

What that means legally, including the “research use only” label, is covered in are peptides legal. FDA’s wording on BPC-157, which sits in the same withdrawn table, is analyzed in what FDA actually said about BPC-157. The wider list is in what cannot legally be compounded.

AOD-9604 next to the GLP-1 trials

The company suggested that diet and exercise drowned out its drug. The trial that led to Wegovy’s approval for weight management had the same setup: semaglutide or placebo, “plus lifestyle intervention.”^[11] The difference is how much the drug added on top.

In STEP 1, people on semaglutide lost 12.7 kg more than people on placebo.^[11] In SURMOUNT-1, the top tirzepatide dose produced about seven times the placebo group’s weight loss.^[12] AOD-9604’s best showing in its decisive trial was less than 1 kg. How GLP-1 weight loss builds month by month is laid out in semaglutide results by week and tirzepatide week by week.

AOD-9604 is not the only growth hormone peptide marketed for fat loss. Sermorelin has never been tested for weight loss in a published trial. Tesamorelin is approved, but only for excess belly fat in adults with HIV who have lipodystrophy. The rest of the menu is sorted by human evidence in the peptide menu. AOD-9604 is the rare peptide that did get a proper obesity trial. The trial answered the question, and the answer was no.

If a clinic or seller offers you AOD-9604

• Ask which trial supports it. If the answer is the 2004 study, its main analysis missed significance, and the larger follow-up trial failed.^[1]
• Notice the route. The human safety data is for tablets and IV doses. There is none for the injection most sellers offer.^[2]
• Check where it comes from. The developer does not make or sell it, and pharmacies cannot lawfully compound it under 503A.^[5][10]
• If you compete in tested sport, it is prohibited.^[13]
• If weight loss is the goal, approved drugs with large published trials exist, and FDA’s own review pointed to them.^[2]