AOD-9604 vs semaglutide

Side by side

AOD-9604 Medium and semaglutide High are both peptides marketed for weight loss ¹. The table is read from our encyclopedia entries.

Two different ideas

AOD-9604 is a 16-amino-acid piece of the end of human growth hormone, the region thought to carry growth hormone's fat-burning effect without its effects on growth or blood sugar. The idea was a targeted fat-loss drug. Semaglutide is a long-acting copy of GLP-1, a gut hormone that reduces appetite and slows stomach emptying, engineered to last a week. One works, in theory, on fat cells; the other on how much people eat.

AOD-9604: strong in rodents, not in people

The animal results were encouraging. Obese Zucker rats given AOD-9604 by mouth for 19 days gained 15.8 g against 35.6 g in controls, less than half the weight (animal study) ². In obese mice, 14 days of injections reduced body weight and fat and restored a fat-cell receptor to lean levels (animal study) ³.

The human programme did not follow through. Its developer ran six placebo-controlled trials in Australia between 2001 and 2006 and ended obesity development in 2007 after a 24-week trial found no significant weight loss (dataset) ¹. A 2013 report written with the developer pooled the six trials, in 893 adults taking it mostly by mouth: it was well tolerated, did not change IGF-1 or glucose tolerance, and headache, the commonest adverse event, occurred at similar rates on AOD-9604 and placebo; the 24-week trial in 536 adults found no significant weight loss (safety analysis) ⁴. Good tolerability is not the same as an effect, and the effect was what failed. The trials also tested oral and intravenous doses, not the injections under the skin in which it is sold today.

AOD-9604 is not approved anywhere as a medicine. A panel convened for the developer later judged it 'generally recognised as safe' for use in foods, a self-determination rather than an FDA decision (dataset) ¹. Anti-doping chemists have validated a urine test for it (laboratory study) ⁵.

Semaglutide: the pivotal trial

In STEP 1, published in 2021, adults with overweight or obesity took semaglutide 2.4 mg weekly or placebo for 68 weeks alongside lifestyle advice. Body weight fell 14.9% with semaglutide against 2.4% with placebo, an average of 15.3 kg against 2.6 kg; 86% lost at least 5% of their weight and half lost 15% or more (randomised trial) ⁶. That trial and others supported approval as Wegovy.

The current US label, effective June 2026, gives 2.4 mg weekly as the usual maintenance dose for weight reduction, allows 1.7 mg, and permits an increase to a maximum of 7.2 mg weekly for some patients who have tolerated 2.4 mg for at least four weeks. It carries a boxed warning about thyroid C-cell tumours seen in rodents (drug label) ⁷. Our semaglutide entry covers the rest of its trials and side effects.

Why the comparison is lopsided

These are not two competing options with different strengths. One is a drug candidate whose key human trial was negative; the other passed large trials and regulatory review. The rodent data that made AOD-9604 interesting is a common pattern in obesity research: many compounds reduce fat in rodents and fail in people. Semaglutide's effect has been reproduced across several large trials.

The safety comparison is different in kind too. AOD-9604's reassuring safety record comes from short company trials of a drug that did little. Semaglutide's side effects, chiefly nausea and other gut symptoms, and its warnings are well characterised because it has been studied in many thousands of people and is monitored after approval (drug label) ⁷.

How they are sold

AOD-9604 is sold online as a research peptide and sometimes as a supplement or 'fat-loss peptide', often with claims drawn from the rodent studies. It is prohibited in sport under the World Anti-Doping Agency's rules, and our AOD-9604 entry records its status. Gray-market 'semaglutide' is also widely sold, and testing has found vials far below their claimed purity, as our marketplace article describes; the lawful route is a prescription and a licensed pharmacy.

If you are considering either

For weight loss, semaglutide is an option to discuss with a clinician, who can check whether it suits you and plan the dose increases the label requires (drug label) ⁷. AOD-9604 has no human evidence of weight loss to weigh against its unknowns. Our guide to legitimate prescriptions explains how to tell a proper weight-loss service from one that only looks the part.

How they compare (as of October 4, 2026)

AOD-9604 reduced fat in obese rodents, but its developer stopped obesity development in 2007 after its largest human trial found no significant weight loss; it was well tolerated, is not approved anywhere, and is banned in sport. Semaglutide reduced weight by about 15% against 2% with placebo over 68 weeks in its pivotal trial and is an approved prescription drug with known side effects. They are presented as alternatives online, but the evidence puts them in different categories.

Frequently asked questions

Does AOD-9604 work for weight loss?

It reduced fat in obese rodents, but its largest human trial found no significant weight loss and development stopped in 2007.

Is AOD-9604 approved?

No. It is not approved anywhere as a medicine; a developer-convened panel called it 'generally recognised as safe' for foods, which is not an FDA approval.

How much weight does semaglutide cause people to lose?

In STEP 1, 14.9% of body weight over 68 weeks on 2.4 mg weekly, against 2.4% with placebo.

Is AOD-9604 safer than semaglutide?

Its short company trials found it well tolerated, but it did not produce weight loss; semaglutide's side effects are well documented and managed under an approved label.

Related on Grey Peptides

• AOD-9604
• Semaglutide
• Semaglutide vs liraglutide
• Legitimate prescriptions

Sources

1. Grey Peptides dataset records for AOD-9604 (approval details: six placebo-controlled trials in Australia 2001-2006; obesity development ended in 2007 after a 24-week trial found no significant weight loss; self-affirmed GRAS) and semaglutide (FDA-approved); read October 4, 2026.
2. Ng, F. M., et al. (2000). Metabolic studies of a synthetic lipolytic domain (AOD9604) of human growth hormone. Horm Res, 53(6), 274-8. PMID: 11146367
3. Heffernan, M., et al. (2001). 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, 142(12), 5182-9. PMID: 11713213
4. Stier H, et al. Safety and tolerability of the hexadecapeptide AOD9604 in humans. J Endocrinol Metab, 2013;3(1-2):7-15 (not PubMed-indexed; read in full September 27, 2026).
5. Cox, H. D., et al. (2015). Detection and in vitro metabolism of AOD9604. Drug Test Anal, 7(1), 31-8. PMID: 25208511
6. Wilding, J. P. H., et al. (2021). Once-Weekly Semaglutide in Adults with Overweight or Obesity. N Engl J Med, 384(11), 989-1002. PMID: 33567185
7. Novo Nordisk. WEGOVY (semaglutide) US prescribing information, sections 1, 2 and boxed warning (DailyMed, effective June 18, 2026); read October 4, 2026.

Educational information, not medical advice. Each dose in this guide names its source, an approved label or a published study. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose.