Synthetic C-terminal human growth hormone fragment
AOD-9604
Not approved — human weight-loss efficacy not demonstrated
An unapproved peptide often discussed for fat loss. It is based on a small part of growth hormone.
6-minute readFull profile reviewed July 30, 2026
Evidence is explained by question. Dosing references show their own check dates.
60-second overview
AOD-9604 at a glance
Why people look into it, what studies found, and what is still unknown.
Why people look into it
Whether it can affect body fat without producing all of growth hormone's effects.
What studies found
The largest study in people did not find meaningful weight loss compared with placebo. That study used an oral product, not an injection under the skin.
What is still unclear
Benefits and safety from injections under the skin remain unproven. Animal findings do not overturn the negative weight-loss trial.
About the evidence and review date
Educational information only. Evidence reviewed through July 30, 2026. Published studies, sponsor announcements, and trials without results are labeled separately. Evidence gaps apply to the specific finding beside them.
Research questions
Why people research it
Each label shows how much evidence supports that question.
Weight lossNot demonstrated
Fat metabolism and lipolysisAnimal or lab research
Avoiding GH/IGF-1 effectsEarly human evidence
Cartilage repair and osteoarthritisAnimal or lab research
Bone-health researchAnimal or lab research
Subcutaneous useNot demonstrated
What studies show
What the evidence supports
The research behind the answer
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.
See each finding and its sources (9)
Mechanistic rationale
AOD-9604 is a synthetic 16-amino-acid C-terminal human-growth-hormone fragment and is not an FDA-approved medicine.
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.
Commercial shorthand such as HGH Fragment 176-191 may not identify the exact form, salt, sequence, purity, or finished product used in research.
The largest AOD-9604 obesity trial did not demonstrate statistically significant weight loss versus placebo and the sponsor terminated obesity development.
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.
The full study was not published in a medical journal, but the sponsor filing and FDA review independently describe the failed primary result.
Available human studies do not establish AOD-9604 as an effective treatment for obesity or fat loss.
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.
The clinical record is old and incompletely published. Absence of efficacy in the studied oral and intravenous programs does not validate other routes or formulations.
The human evidence reviewed by FDA involved oral or intravenous administration, not the commonly marketed subcutaneous route.
FDA did not identify human exposure through subcutaneous or transdermal administration in the published record it reviewed.
Safety, bioavailability, immunogenicity, and efficacy can differ by route and formulation. Oral or IV experience cannot be assumed to describe compounded injections.
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.
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.
The publication included company employees or consultants and did not provide a modern integrated analysis with complete event-level data or long-term follow-up.
AOD-9604 produced weight and lipid-metabolism effects in mouse models, but those results did not establish human weight-loss efficacy.
Preclinical work described fat oxidation, lipolytic sensitivity, and beta-adrenergic pathway changes in mice.
The subsequent human obesity program failed its primary endpoint. Animal effects should not be converted into human expectations or administration plans.
Peer reviewedMouse body-weight and beta-adrenergic findings
Cartilage-repair claims for AOD-9604 are supported by a rabbit osteoarthritis model, not by controlled human trials.
A small rabbit experiment reported improved cartilage and lameness measures after intra-articular treatment.
FDA did not identify clinical studies in people with osteoarthritis or osteoporosis. An induced animal model cannot establish human regeneration or pain benefit.
Regulatory sourceNo clinical studies identified for osteoarthritis or osteoporosis
Peer reviewedRabbit morphology, histology, and lameness outcomes
Other human evidence
FDA's compounding review identified characterization, impurity, aggregation, immunogenicity, and limited-safety concerns for AOD-9604-related bulk substances.
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.
The 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.
Regulatory sourceChemistry, human safety, and compounding conclusions
No direct evidence located
No regulator-approved AOD-9604 reconstitution, storage, stability, dose, or administration standard exists.
AOD-9604 is not a component of an FDA-approved drug. Supplier documents and compounded-product practices do not create an approved product standard.
Peptide form, impurities, concentration, excipients, manufacturing, route, and storage can materially change quality and risk.
Regulatory sourceProduct status, characterization, and stability review
Risks & unknowns
What needs caution
Reported side effects
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 evidence
The publication included company employees or consultants and did not provide a modern integrated analysis with complete event-level data or long-term follow-up.
FDA's compounding review identified characterization, impurity, aggregation, immunogenicity, and limited-safety concerns for AOD-9604-related bulk substances.
Other human evidence
The 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.
Missing reports do not establish safety. Findings apply to the product, route, amounts, population, comparison, and follow-up studied.
Side-effect frequency, study withdrawals, and gaps
How often side effects occurred
The available information does not reliably show how often particular side effects occur.
Evidence boundary
Under-detected or under-reported events must not be described as rare.
Why people stopped in studies
Relay has not verified which side effects led people to stop treatment in studies.
Evidence boundary
This is an evidence gap, not proof that discontinuations did not occur.
Emergency instructions
This profile does not contain verified, product-specific emergency instructions.
Evidence boundary
Relay does not infer emergency guidance from study discontinuations, mechanism, or incomplete adverse-event reporting.
Dosing references
Dosing & preparation
Each table labels its source and applies only to the named route, product, or study. An online example or community report is not an approved dose.
Route: Oral · Taken by mouth
FDA review · historical trial regimensWhat this means
A regulator’s assessment of the named use. The review and its limitations are not themselves an approved dosing schedule.
AOD-9604 · oral trials summarized by FDA
FDA's bulk-substance review summarizes historical obesity trials and their limitations; it is not a product approval.
Amount in this source
Trial-specific oral dose groups
Frequency
Daily
Treatment period
12 or 24 weeks by study
AOD-9604 · oral trials summarized by FDA
Historical study
Separate daily groups
Treatment period
METAOD005
1, 5, 10, 20, or 30 mg
12 weeks
METAOD006
0.25, 0.5, or 1 mg
24 weeks
The larger obesity program did not establish the intended weight-loss benefit. Oral amounts do not establish an injectable AOD schedule.
FDA · AOD-9604 bulk-substance review Clinical effectiveness and safety · METAOD005 / METAOD006This reference checked Oct 20, 2026. The full-profile review date is shown at the top.
Formulation & handling · Oral
This source does not establish a mixing volume or storage period for independently sourced powder. Use formulation-specific instructions; the study amount alone is not a reconstitution recipe.
Starting dose, maintenance, and trial targets explained
Starting dose: the amount used at the beginning of the named label schedule or trial.
Maintenance: the ongoing amount described by that product label.
Trial target: the amount assigned to a study group. Different groups may stop increasing at different targets.
Other source records, populations, and limits · all routes
Direct human study
AOD-9604 oral obesity study material
Amount in this source
See the named dosing references above; this additional source record does not add a verified amount.
Frequency
Once daily in separate study arms
Route
Oral administration
Duration
12 weeks after a two-week run-in
Population, study design, and limitations
FDA's evidence review describes a randomized oral study in adults with obesity; the larger development program did not establish a weight-loss benefit.
Population: 300 men and women aged 30-60 years with obesity
Design: Randomized, double-blind, placebo-controlled oral dose-ranging study
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.
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.
Why this matters
A plausible mechanism can explain why a study was attempted. It does not prove that the compound improves a human outcome.
Signals and targets
No validated human therapeutic receptor targetbeta-3 adrenergic pathway - indirect preclinical associationHuman growth hormone receptor - no demonstrated activation in summarized assays
Proposed biological steps
C-terminal human-growth-hormone fragment signaling
Lipolysis and fat-oxidation signals in animal models
Indirect beta-adrenergic pathway interaction in mice
Research reference
How mature is the evidence?
A reference for the studies, populations, and routes behind this profile.
Research depthMeaningful but incomplete human program
Historical studies include a large negative Phase 2B obesity trial, but reporting and route coverage are incomplete.
Why this matters
Research depth describes how large and mature the overall record is. It does not tell you whether the results were positive.
Evidence confidenceHigh for the tested obesity outcome
The 536-person trial strongly challenges oral weight-loss claims; confidence is far lower for other outcomes and unstudied injection routes.
Why this matters
Confidence describes how reliable and consistent the conclusions are. It can be high for one outcome and low for another.
Strongest evidenceA 536-person randomized Phase 2B obesity trialWhy this matters
The strongest evidence type shows what the best-supported conclusions are actually based on.
Human evidenceControlled oral evidence is negative for obesity; human SubQ evidence is absentWhy this matters
Human findings are more directly relevant than animal or laboratory results, but they still apply only to the populations and outcomes studied.
Schedules studiedOnce daily in separate study arms; 12 weeks after a two-week run-in
Amounts studiedWithheld: this record provides research context without a transferable amountWhy this matters
These are exposures used in cited research for a specific route and population—not an instruction for an individual.
Half-lifeNot established for this exact editorial recordWhy this matters
Half-life describes how long it takes the measured amount in the body to fall by half. It is not a dosing recommendation.
Route evidenceFDA's evidence review describes a randomized oral study in adults with obesity; the larger development program did not establish a weight-loss benefit.Why this matters
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.
Studies
Study-by-study record
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.
Why this matters
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.
Animal studyPeer reviewed
Effect of Intra-articular Injection of AOD9604 with or without Hyaluronic Acid in Rabbit Osteoarthritis Model
DurationWeekly injections during weeks 4-7; assessment at week 8
Design and population
Randomized treatment groups in collagenase-induced knee osteoarthritis
32 New Zealand white rabbits
Outcomes measured
Cartilage morphology
Histopathology
Lameness duration
What was reported
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 and important limits
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.
Animal studyPeer reviewed
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
Chronic treatment in obese and beta-3 adrenergic receptor knockout mice
Obese and genetically modified mice
Outcomes measured
Body weight and body fat
Lipolytic sensitivity
Beta-3 adrenergic receptor expression
Energy expenditure and fat oxidation
What was reported
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 and important limits
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.
Animal studyPeer reviewed
Metabolic studies of a synthetic lipolytic domain (AOD9604) of human growth hormone
Early experiments reported lipid-metabolism effects without the full growth-promoting profile of human growth hormone.
Study administration and important limits
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.
Controlled human studyRegulatory source
FDA AOD-9604 review - METAOD005 oral obesity study
Randomized, double-blind, placebo-controlled oral dose-ranging study
300 men and women aged 30-60 years with obesity
Outcomes measured
Weekly rate of weight loss
Waist circumference
Lipids
Safety and tolerability
What was reported
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 and important limits
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.
Controlled human studyRegulatory source
FDA AOD-9604 review - METAOD002 intravenous crossover study
DurationFour single-dose periods separated by seven-day washouts
Design and population
Double-blind intravenous crossover dose-escalation study
23 men aged 19-50 years with obesity
Outcomes measured
Non-esterified fatty acids
Short-term weight change
Safety
What was reported
A rise in non-esterified fatty acids was reported, but average weight loss over three weeks was not statistically different from placebo.
Study administration and important limits
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.
Controlled human studyPrimary source
Metabolic's obesity drug - Phase 2B clinical trial results
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
Outcomes measured
Weight loss at 12 weeks
Weight loss at 24 weeks
Waist circumference
Body-fat change
Metabolic risk factors
Safety and tolerability
What was reported
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 and important limits
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.
Other human evidencePrimary source
Safety and Tolerability of the Hexadecapeptide AOD9604 in Humans
Summary of six randomized, double-blind, placebo-controlled trials
Healthy or obese adults exposed to oral or intravenous AOD-9604
Outcomes measured
Adverse events
Vital signs and laboratory tests
IGF-1
Glucose tolerance
Anti-AOD-9604 antibodies in selected participants
What was reported
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 and important limits
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.
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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
2001-12-01 · PMID 11713213 · DOI 10.1210/endo.142.12.8522