AOD-9604

What AOD-9604 is and how it works

AOD-9604 is a synthetic peptide of sixteen amino acids: the carboxy-terminal sequence 177-191 of human growth hormone, plus an additional tyrosine at the amino terminus, with a disulfide bond closing two of the residues into a ring. FDA's substance registry files it under one unique ingredient identifier that also carries the names AOD9604, LAT-8881 and LAT8881 — four names for a single substance. That is not a trivia point. The modern research on this molecule is published under the other name, and a reader who searches only for AOD-9604 will not find it.

The peptide came out of Frank Ng's laboratory at Monash University, where the C-terminal region of growth hormone was mapped as a functional domain distinct from the part of the hormone that signals through its receptor. A solution structure of the cyclic fifteen-residue version — the same ring without the extra tyrosine — was determined by two-dimensional NMR and reported to retain some structural similarity to the corresponding region of the intact protein.^[6] Construct names in this literature are not used consistently and it matters which one an experiment used: hGH 177-191, the tyrosine-free cyclic peptide and AOD9604 are different molecules on paper, and AOD-9401 is a different peptide again, which FDA's own evaluation excluded by name as out of scope.

The proposed mechanism is that growth hormone behaves as a pro-hormone whose C-terminal domain carries lipid-metabolism actions without the receptor-mediated ones. In obese ob/ob mice treated for 14 days, both intact human growth hormone and the fragment reduced body-weight gain, raised in vivo fat oxidation and raised plasma glycerol; in the same paper's cell assays the fragment neither competed for the growth hormone receptor nor induced proliferation through it, while the intact hormone did both.^[7] That receptor-independence result is the load-bearing one for everything the compound is marketed on, and it has been restated since: a 2023 paper working under the molecule's other name states plainly that it acts independently of the growth hormone receptor.^[14]

Whether the fragment is lipolytic at all is contested inside the originating group's own published record. The 1993 paper that first characterized hGH 177-191 concluded the action was antilipogenic — a suppression of fat synthesis — and said in its own words that no significant lipolytic effect was found, measured as glycerol release from fat pads of treated rats.^[2] Later papers from the same laboratory report increased lipolytic activity in adipose tissue from treated rats and raised plasma glycerol.^[5] Knockout work concluded that the lipolytic actions of both the hormone and the fragment are not mediated directly through the beta-3 adrenoceptor, although both raised beta-3 adrenoceptor RNA in obese mice toward lean levels.^[8] "Lipolytic fragment" is the name the compound travels under; it is not a settled description of what it does.

What the research actually shows

In obese rodents, the weight findings are real and consistent. Genetically obese Zucker rats given 500 micrograms per kilogram by mouth once daily for 19 days gained 15.8 grams against 35.6 grams in controls — a reduction of more than half in weight gain, not a loss of existing weight — with increased lipolytic activity in adipose tissue and, by euglycemic clamp, no adverse effect on insulin sensitivity, which the authors contrasted explicitly with chronic intact human growth hormone.^[5] Obese ob/ob mice given the fragment by mini-osmotic pump for 14 days showed the same direction of effect on weight gain, fat oxidation and glycerol.^[7] Separate 14-day intraperitoneal dosing reduced body weight and body fat in obese mice.^[8] Chronic treatment of ob/ob mice with the tyrosine-free hGH 177-191 construct reduced cumulative body-weight gain and adipose tissue mass, with adipose lipogenesis significantly inhibited.^[4] Four experiments, one laboratory, one era, and animals bred or fed to be obese.

In people, there is a development programme and no published results. A 2004 development review records that the sponsor was developing AOD-9604 for obesity and that phase IIa trials were underway by February 2002.^[9] Nothing followed it. The company studies that were run — including the pivotal one — are described below under Legal and regulatory status, because the only places they survive in the public record are a published regulatory evaluation and a company market filing, and attaching those numbers to a journal citation that does not contain them would be a false statement about the source.

The molecule's strongest recent work is filed under its other name and is about pain, not fat. A 2026 study used a photoaffinity conjugate of the active metabolite to pull down lanthionine synthetase C-like protein 1 as the binding target in rodent spinal cord, confirmed it with siRNA knockdown that blocked the peptide's activity, and reported reversal of mechanical allodynia across several rodent neuropathic models including chronic constriction injury.^[17] An independent systematic review of investigational postherpetic-neuralgia drugs lists the same molecule under LANCL activation among agents in advanced clinical development.^[15] The authors of that 2026 mechanism paper include employees, shareholders and patent holders of the sponsoring company, which is disclosed in the paper; the postherpetic-neuralgia review declares no conflict of interest.

One animal joint study exists, and its headline is a two-agent result. Thirty-two rabbits with collagenase-induced knee osteoarthritis received weekly intra-articular saline, 6 mg hyaluronic acid, 0.25 mg AOD9604, or both agents together. Hyaluronic acid alone and AOD9604 alone each scored better than saline on gross and histopathological measures; the group given both scored better than either single-agent group and had the shortest lameness period.^[13] Hyaluronic acid is doing work in that result, and it is a rabbit result.

The analytical literature is the most independent part of the record and it is not about efficacy. A United States anti-doping laboratory validated a urine method with a detection limit of 50 pg/mL and identified six metabolites, one of which is substantially more stable than the parent compound.^[12] A German sports-medicine institute established that the fragment does not influence the standard growth hormone isoform immunoassay — meaning it does not register as growth hormone in the test built to catch growth hormone.^[10] A national public-health institute published a case report on identifying AOD9604 in an unknown pharmaceutical preparation seized by that country's authorities.^[11]

Where the evidence is weak

The human obesity trials were run, were largely negative, and were never published. Everything else on this page is downstream of that. Searching PubMed on 1 September 2026 for AOD-9604 OR AOD9604 OR LAT8881 OR LAT-8881 returned 27 records; adding randomized OR randomised OR placebo with obesity OR weight loss returned one, a 2026 narrative review. No results paper for any of the sponsor's obesity trials appears in the indexed literature. An unpublished trial is not evidence a reader can check, which is why this page's compound-level grade is animal_only rather than human_rct: randomized human trials of this compound exist, none of them has been published, and the route the compound is most often presented by has no human data at all.

The premise that the fragment separates fat effects from glucose effects is partly contradicted by the older literature on the same sequence. Normal rats given nanomolar quantities of the reduced, carbamidomethylated 177-191 peptide developed significant hyperglycaemia and insulin resistance, and the authors mapped an insulin-antagonistic core of growth hormone to residues 178 to 190 — inside the sequence AOD-9604 is built from.^[1] In adipocytes isolated from obese Zucker rats the fragment reduced basal and insulin-stimulated glucose uptake, and at equimolar concentrations it was more potent than intact human growth hormone.^[3] The favourable metabolic findings come from later, chronic-dosing experiments in obese animals; the unfavourable ones come from earlier, acute experiments in normal ones. Neither set cancels the other, and "no diabetogenic effect" is a claim about the first kind of experiment only.

Read-across from full-length growth hormone runs both ways and neither direction is licensed here. In the study that treated obese and lean mice for 14 days by osmotic pump, the same authors ran binding and proliferation assays in cells transfected with the human growth hormone receptor and reported that the fragment does not compete for that receptor and does not induce cell proliferation through it, unlike the intact hormone.^[7] Growth hormone's own efficacy evidence therefore does not flow to the fragment, and the fragment's rodent results say nothing about the hormone. The two were tested side by side in several of the cited papers, and in those experiments the intact hormone is the arm that produced hyperglycaemia and cell proliferation.

One laboratory, one country, one decade. Every rodent efficacy paper above comes from the same Monash group, published between 1993 and 2001, and no independent laboratory has replicated the weight findings. The independent work that does exist — the anti-doping and forensic analytical papers, and the two 2026 reviews — characterizes the molecule and its regulatory position rather than testing whether it works.^[16]

The most-quoted marketing line is about a different peptide. The claim that the compound increased lipolytic activity in adipose tissue from obese rodents and humans traces to work on AOD-9401, which FDA's evaluation excluded by name as a different peptide outside the scope of its assessment. Nothing about AOD-9401 is evidence about AOD-9604.

No published study of the marketed three-peptide combination exists. The compound is commonly presented alongside CJC-1295 and ipamorelin, both of which have their own pages here. A PubMed search on 1 September 2026 for AOD9604 with CJC-1295 or ipamorelin returned five records — three narrative reviews and two analytical-methods papers — none of which reports a study of those peptides administered together.^[18]

Long-term safety in people is unstudied, and a food-ingredient status says nothing about whether something works. The GRAS question is dealt with below; it is a safety-for-food judgement, made privately, and it was never a finding about weight loss.

Legal and regulatory status

AOD-9604 is not approved by the FDA for any indication, and human evidence for the use it is marketed for is absent from the published literature. Queried on 1 September 2026 against a positive control that returned real records, Drugs@FDA held no application under any spelling of the name or under either registry synonym, and the approved-labeling database held no label. The National Drug Code directory does return records — three to four depending on spelling — but every one is registered as a bulk ingredient by an active-pharmaceutical-ingredient manufacturer, with no brand name and no finished product; one is self-declared for prescription compounding, which is the registrant's own statement and not an FDA position. A non-empty NDC response is not an approval. Two FDA drug-enforcement records exist, both Class II recalls of compounded injectable AOD-9604 preparations, both for lack of assurance of sterility.

FDA has formally evaluated this compound, and the outcome is the strongest regulatory fact on this page. In a briefing document dated November 2024 for a Pharmacy Compounding Advisory Committee meeting held on 4 December 2024, FDA assessed AOD-9604 free base and AOD-9604 acetate for inclusion on the section 503A bulk drug substances list. Both nominations had been withdrawn by their nominators; FDA states in the document that it evaluated the substances at its own discretion anyway. Its conclusion on effectiveness, in its own words, is that "there is a lack of evidence to support the effectiveness of AOD-9604 for the treatment of obesity for any route of administration," and that "in most of the studies we identified, AOD-9604 failed to show benefit when compared to placebo." On safety it concluded that such use "may raise safety concerns," that "there is no information to assess the pharmacokinetic or pharmacodynamic effects" of either substance in humans, and that it "did not find information on the proposed subcutaneous and transdermal use" of either substance in humans — the routes most readers arrive here having been told about. The committee then voted, and the official minutes record the result: 0 yes, 12 no, 0 abstentions against placing either substance on the list. The compound is absent from the current published 503A category lists, revised 14 May 2026, because the nominations were withdrawn — not because FDA declined to look.

The human trial results, as that evaluation words them. An intravenous dose-escalation study in 23 adults with obesity produced on average 0.58 kg of weight loss over three weeks, "not statistically different from placebo." An oral study in 16 men with obesity found "no statistically significant weight loss compared with placebo." A 12-week study in 300 patients produced its largest effect at the lowest of five doses, and FDA's comment is that the authors' claim of weight reduction "is based on small differences between the treatment and placebo groups which has unclear meaningful therapeutic effects." The pivotal trial enrolled 536 people and randomized 502 to oral peptide or placebo for 24 weeks alongside a supervised diet and exercise programme; it did not find a significant difference on its primary endpoint of weight loss at 12 weeks, and the company announced in a market filing that the results "do not support the commercial viability of the drug as a treatment for obesity" and that development for the condition was terminated. In the 300-patient study, five subjects reported serious adverse events that were malignancies or neoplasms across several dose arms; the investigators considered none related and argued a dose effect could be excluded, and FDA's stated position is that the information is insufficient to conclude the cancers were unrelated. FDA also records nonclinical signals from an initial toxicology assessment: effects on bone in rats dosed orally for 13 weeks, signals suggestive of liver toxicity in monkeys dosed orally for nine months, and equivocal mutagenic signals. And across the human studies that evaluation identified, IGF-1 was not increased — the marker intact growth hormone does move, and the point on which the fragment and the hormone are said to differ. That is a finding from the agency's review of the unpublished human record, not from any paper a reader can retrieve.

The "FDA GRAS" claim is false, and what actually happened is on the record. In June 2012 the sponsor's listed parent announced that AOD9604 had received a conditional GRAS determination "by an expert scientific panel," with full application of the status conditional on publishing the existing safety studies in a peer-reviewed journal; the company's own chief executive described it in that announcement as "a self-affirmed conditional GRAS status." Self-affirmation means a private panel, retained by the sponsor, reached a conclusion. Queried on 1 September 2026 against a positive control that returned 48 notices, FDA's GRAS Notice Inventory held no record for AOD-9604 or AOD9604. FDA has never reviewed or affirmed that conclusion and there is no GRAS notice on file. Whether a new dietary ingredient notification was ever filed, and whether any warning letter has issued, could not be verified at a primary source and this page asserts neither.

In tested sport the position is settled and long-standing. The 2026 World Anti-Doping Code International Standard Prohibited List — in force from 1 January 2026, retrieved from the World Anti-Doping Agency on 1 September 2026 via the United States Anti-Doping Agency's prohibited-list page — names AOD-9604 explicitly at section S2.2.3, under growth hormone, its analogues and fragments, in the line reading "growth hormone fragments, e.g. AOD-9604 and hGH 176-191". Section S2 is prohibited at all times, in and out of competition. That listing is corroborated in the indexed literature: the anti-doping laboratory that validated the urine method states in its own abstract that the peptide is banned by the World Anti-Doping Agency.^[12] A 2026 sports-medicine review places the compound among unapproved peptides marketed direct to patients, operating largely outside regulatory oversight, for which rigorous human safety data are scarce.^[16]

PHL does not sell peptides, does not prescribe, and does not tell anyone where to obtain anything.

Questions to bring to a provider

The useful conversation about this compound starts by separating what was demonstrated in rodents from what was tested in people and never reported:

• What is the published human evidence, as opposed to the trials that were run and not published, and what would it change if the pivotal 502-patient trial had reported a positive result?^[9]
• The rodent weight results reduced weight gain in animals bred or fed to be obese. What does that predict, if anything, for an adult who is already at a stable weight?^[5]
• The marketing premise is that this fragment gives growth hormone's fat effects without its glucose effects. Given that the same C-terminal sequence produced hyperglycaemia and insulin resistance in normal rats, what baseline and follow-up glucose measurements would make sense here?^[1]
• What is actually in unapproved material, and how would anyone know, given that identifying this peptide in seized preparations required a laboratory?^[11]
• If the interest is joint or cartilage related, what should be made of a single rabbit study in which hyaluronic acid alone also beat saline?^[13]
• Given that a validated urine assay exists and that one of this peptide's metabolites is considerably more stable than the parent compound, how long would an anti-doping laboratory expect a single exposure to remain detectable?^[12]
• Is there a reason to think the recent work under the molecule's other name — a spinal-cord target and rodent neuropathic-pain models — has any bearing on a weight-loss question?^[17]

A clinician who says "the animal data are real, the human trials were run and came back negative, and the part you were told about the FDA is not true" is describing this record accurately.