What is it?
AOD-9604 is an unapproved synthetic fragment based on one end of human growth hormone. It is often discussed as a fat-loss compound.
Gathering the record
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Relay is organizing the evidence and source boundaries.
Gathering the record
Relay is organizing the evidence and source boundaries.
Synthetic C-terminal human growth hormone fragment
AOD-9604 is a synthetic fragment derived from the C-terminal region of human growth hormone. Although animal studies suggested effects on fat metabolism, the largest human obesity trial did not show statistically significant weight loss versus placebo and the sponsor ended development for obesity. It is not FDA approved, and human evidence does not cover the subcutaneous route commonly marketed today.
60-Second Overview
Start with what it is, why it matters, what research has shown, and what remains unknown. The science follows after the orientation.
Start here. These four answers explain why the compound matters before the page introduces the deeper science.
AOD-9604 is an unapproved synthetic fragment based on one end of human growth hormone. It is often discussed as a fat-loss compound.
Animal experiments suggested possible effects on fat metabolism, leading researchers to test whether the fragment could change weight without reproducing all of growth hormone's effects. Cartilage claims later emerged from a separate rabbit model.
The largest human obesity trial used oral AOD-9604 and did not find statistically significant weight loss versus placebo; the sponsor then ended obesity development. Smaller human records used oral or intravenous administration, not the subcutaneous route commonly marketed now.
Human subcutaneous exposure, long-term safety, product identity, immune reactions, preparation, and clinical benefit remain unresolved. Animal findings do not overturn the negative human obesity result or establish a human regimen.
The research depth, routes, studies, and primary sources below explain how Relay knows—and where the evidence stops.
Research context
Published research has investigated this compound using the following study designs.
These records explain what researchers did. They are not instructions, recommendations, or a transferable protocol.
FDA's evidence review describes a randomized oral study in adults with obesity; the larger development program did not establish a weight-loss benefit.
Reported study administration—not a recommendation.
Research at a glance
Evidence depth, confidence, and route context explain how Relay knows—not what anyone should do.
Historical studies include a large negative Phase 2B obesity trial, but reporting and route coverage are incomplete.
Research depth describes how large and mature the overall record is. It does not tell you whether the results were positive.
The 536-person trial strongly challenges oral weight-loss claims; confidence is far lower for other outcomes and unstudied injection routes.
Confidence describes how reliable and consistent the conclusions are. It can be high for one outcome and low for another.
The strongest evidence type shows what the best-supported conclusions are actually based on.
Human findings are more directly relevant than animal or laboratory results, but they still apply only to the populations and outcomes studied.
Route-specific record
These are exposures used in cited research for a specific route and population—not an instruction for an individual.
Half-life describes how long it takes the measured amount in the body to fall by half. It is not a dosing recommendation.
Evidence can change by administration method. Findings from one route should not automatically be applied to another.
Evidence boundary: The available account is an FDA review of an abstract and pooled sponsor material rather than a complete peer-reviewed efficacy paper. Oral and intravenous human records do not support subcutaneous administration, generic-vial preparation, or cartilage benefit in people. Amounts shown describe cited research exposure—not a dosage recommendation.
Detailed evidence
Start with the strongest supported conclusion and its main uncertainty. Claim-level records below show how the evidence changes by question, population, route, formulation, and study design.
The 536-person randomized OPTIONS Phase 2B obesity study is the most decision-relevant human evidence: oral AOD-9604 did not significantly improve weight loss over placebo at 12 or 24 weeks, and the sponsor terminated obesity development.
This is the strongest supported conclusion in the current human evidence—not a summary of every claim made about the compound.
Long-term and route-specific safety - especially for subcutaneous compounded products - because no human subcutaneous study, adequate pharmacokinetic program, approved product standard, or modern confirmatory efficacy trial was identified.
Keeping the main uncertainty visible prevents an early or promising finding from looking more settled than it is.
Questions people bring to the evidence
Research questions—not promises of benefit.
The researched molecule is Tyr-hGH177-191: amino acids 177-191 of human growth hormone with an additional N-terminal tyrosine and a disulfide bond.
The OPTIONS program enrolled 536 adults and tested daily oral AOD-9604 alongside a formal diet-and-exercise program. The primary 12-week and secondary 24-week comparisons were negative.
Several small studies reported metabolic markers or limited dose/subgroup signals, but most did not show significant weight loss and the adequately sized follow-up trial was negative.
FDA did not identify human exposure through subcutaneous or transdermal administration in the published record it reviewed.
Selected antibody tests were negative and pooled short-term tolerability was described as similar to placebo. FDA emphasized incomplete case details, heterogeneous studies, and missing route-specific data.
Preclinical work described fat oxidation, lipolytic sensitivity, and beta-adrenergic pathway changes in mice.
A small rabbit experiment reported improved cartilage and lameness measures after intra-articular treatment.
FDA found the free base and acetate insufficiently characterized for critical peptide impurities and noted that injectable peptide products may present route-specific immunogenicity risks.
AOD-9604 is not a component of an FDA-approved drug. Supplier documents and compounded-product practices do not create an approved product standard.
Mechanisms
AOD-9604 is Tyr-hGH177-191, a 16-amino-acid cyclic peptide based on residues 177-191 of human growth hormone with an added N-terminal tyrosine. Preclinical studies reported lipolysis, fat oxidation, body-weight effects, and beta-adrenergic pathway changes in animal models. Six company-sponsored randomized studies exposed people to oral or intravenous AOD-9604, but efficacy reporting was incomplete and the 536-person OPTIONS Phase 2B program failed its primary weight-loss endpoint. The available pooled safety summary did not show consistent activation of the GH/IGF-1 axis, yet FDA concluded that clinical safety information, pharmacokinetic data, subcutaneous-route evidence, product characterization, and long-term risk information remain insufficient.
A plausible mechanism can explain why a study was attempted. It does not prove that the compound improves a human outcome.
Studies
Study arms are reported for transparency. They describe what researchers did in a defined record and do not transfer across identities, routes, formulations, or populations.
A later trial phase can ask a more mature question, but it does not guarantee a positive result, regulatory approval, or relevance outside the studied population.
Randomized treatment groups in collagenase-induced knee osteoarthritis
32 New Zealand white rabbits
The rabbit study reported better cartilage and lameness measures with AOD-9604 than saline, with the combination arm performing best in that model.
Study administration: Intra-articular saline, hyaluronic acid, AOD-9604, or AOD-9604 plus hyaluronic acid
Limitations: This was an induced rabbit model using intra-articular administration. It does not demonstrate cartilage regeneration, pain relief, or osteoarthritis benefit in humans.
Chronic treatment in obese and beta-3 adrenergic receptor knockout mice
Obese and genetically modified mice
AOD-9604 reduced weight and fat in obese mice and altered beta-3 adrenergic pathway measures. Effects were attenuated in knockout mice, while acute energy-expenditure effects still occurred.
Study administration: AOD-9604, full-length human growth hormone, or control
Limitations: Mouse weight and receptor-pathway findings did not translate into a successful human obesity program. They support mechanism research, not human efficacy or dosing.
In-vitro and animal metabolic studies
Laboratory systems and animal models
Early experiments reported lipid-metabolism effects without the full growth-promoting profile of human growth hormone.
Study administration: Synthetic AOD-9604 exposure
Limitations: The experiments were preclinical and preceded the negative larger human trial. They cannot establish weight-loss efficacy or safety in people.
Randomized, double-blind, placebo-controlled oral dose-ranging study
300 men and women aged 30-60 years with obesity
A meeting abstract described small, non-linear differences in weekly weight loss and limited subgroup signals. FDA found the sparse methods and results insufficient to establish a clinically meaningful benefit, and no full publication was located.
Study administration: Once-daily oral AOD-9604 across five studied dose groups or placebo; research protocol only
Limitations: The available account is an abstract and pooled safety summary rather than a full peer-reviewed efficacy report. Missing numerical detail, multiple doses, and subgroup interpretation substantially limit confidence.
Double-blind intravenous crossover dose-escalation study
23 men aged 19-50 years with obesity
A rise in non-esterified fatty acids was reported, but average weight loss over three weeks was not statistically different from placebo.
Study administration: Single intravenous AOD-9604 administrations across three studied dose levels and placebo; research protocol only
Limitations: This was a very small, short intravenous study. A transient metabolic marker cannot establish durable fat loss, and the route does not support claims about subcutaneous use.
Randomized, double-blind, placebo-controlled multicenter obesity trial with a supervised diet and exercise program
Adults aged 18-65 years with obesity and BMI 30-45 kg/m2
The sponsor reported that weight loss versus placebo was too small to reach statistical significance at the primary 12-week endpoint or the 24-week secondary endpoint. Development for obesity was terminated.
Study administration: Once-daily oral AOD-9604 across three studied dose groups or placebo; research protocol only
Limitations: The complete clinical study report was not located in the medical literature. Public results come from a company filing and FDA's later regulatory review, but the negative primary result is clear and directly relevant.
Summary of six randomized, double-blind, placebo-controlled trials
Healthy or obese adults exposed to oral or intravenous AOD-9604
The publication reported no consistent IGF-1 or glucose-tolerance effect and no detected anti-AOD-9604 antibodies in tested subsets. FDA later judged the safety record too limited and heterogeneous for firm conclusions, particularly for long-term or subcutaneous use.
Study administration: Oral or intravenous AOD-9604 under six company-sponsored clinical protocols
Limitations: This was a sponsor-linked pooled summary with incomplete event-level detail, varying designs and formulations, and no human subcutaneous exposure. It cannot establish long-term or route-specific safety.
Safety snapshot
A sponsor-linked summary of six trials reported no consistent IGF-1 or glucose-tolerance effect, but the available safety record remains insufficient for long-term or subcutaneous use.
Other human evidenceThe publication included company employees or consultants and did not provide a modern integrated analysis with complete event-level data or long-term follow-up.
Open sourceThe current record does not support a reliable common-versus-uncommon frequency split.
Evidence boundaryUnder-detected or under-reported events must not be described as rare.
FDA's compounding review identified characterization, impurity, aggregation, immunogenicity, and limited-safety concerns for AOD-9604-related bulk substances.
Other human evidenceThe review addresses proposed compounded products and does not evaluate every possible manufactured formulation. It nevertheless directly challenges assumptions that any marketed AOD-9604 material is interchangeable with trial material.
Open sourceThe current record does not identify a reliable compound-specific pattern of events that caused study discontinuation.
Evidence boundaryThis is an evidence gap, not proof that discontinuations did not occur.
No compound-specific patient-facing urgent-action threshold is established in the current Relay record.
Evidence boundaryRelay does not infer emergency guidance from study discontinuations, mechanism, or incomplete adverse-event reporting.
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2015-07-01 · PMID 26275694
2013-04-01 · DOI 10.4021/jem157w
2007-02-21
2001-12-01 · PMID 11713213 · DOI 10.1210/endo.142.12.8522
2000-01-01 · PMID 11146367 · DOI 10.1159/000053183