AOD-9604
A modified fragment of human growth hormone studied specifically for fat metabolism without the growth-promoting effects of full GH.
What is AOD-9604?
AOD-9604 is a modified fragment of human growth hormone (specifically amino acids 177-191 with an added tyrosine). It was designed to isolate the fat-metabolizing properties of growth hormone without its growth-promoting effects. It received GRAS (Generally Recognized as Safe) status from the FDA as a food additive, though it is not approved as a drug.
What AOD-9604 Is Investigated For
AOD-9604 is a growth-hormone-fragment peptide investigated primarily for fat loss without the growth-promoting or insulin-desensitizing effects of full GH, with a smaller body of emerging work on cartilage repair and osteoarthritis. The central — and uncomfortable — fact is that its Phase IIb obesity trial did not meet its primary weight-loss endpoint versus placebo, meaning the headline 'fat-burning fragment' marketing is directly contradicted by the most rigorous human trial ever conducted on the molecule. The strongest supporting evidence is actually in an orphan area: a rabbit osteoarthritis study where intra-articular AOD-9604 enhanced cartilage regeneration and outperformed hyaluronic acid, though this is a single preclinical study with no human joint data. AOD-9604 holds GRAS status as a food additive — a regulatory category that evaluates food safety, not drug efficacy, and is frequently conflated with FDA drug approval in consumer marketing. The honest framing is a peptide whose mechanistic premise did not translate in a properly powered human obesity trial, with a clean safety signal and possible but unproven orthopedic applications.
History & Discovery
AOD-9604 was developed in the 1990s at Monash University by a team led by Frank Ng and Michael Heffernan, and subsequently carried into clinical development by the Australian biotech Metabolic Pharmaceuticals. The design premise was mechanistic: the C-terminal fragment of human growth hormone (amino acids 176–191) was reported to contain the 'lipolytic domain' responsible for GH's fat-mobilizing effects, while the growth-promoting and diabetogenic properties were believed to reside elsewhere in the molecule. AOD-9604 adds an N-terminal tyrosine residue to that fragment to improve stability. The company's bet was that isolating the lipolytic domain would produce a weight-loss drug without GH's acromegalic, insulin-desensitizing, or IGF-1-raising liabilities. Metabolic Pharmaceuticals advanced AOD-9604 into an extensive clinical program for obesity, culminating in a Phase IIb trial published in the late 2000s. The key result was negative: AOD-9604 did not produce statistically significant weight loss beyond placebo at the doses and duration studied, and the program was ultimately not carried forward to Phase III approval. The compound was subsequently licensed and repositioned — including toward osteoarthritis and cartilage-repair indications — and acquired GRAS (Generally Recognized as Safe) status as a food-additive ingredient, a regulatory category entirely separate from drug approval. The wellness and research-chemical markets adopted AOD-9604 in the 2010s largely on the original 'fat-burning fragment' marketing, a framing that the Phase IIb data did not support.
How It Works
AOD-9604 is a small piece of growth hormone that appears to stimulate fat breakdown (lipolysis) and inhibit fat formation (lipogenesis) without affecting blood sugar or growth. It targets fat cells specifically.
AOD-9604 mimics the lipolytic domain of human GH. It stimulates lipolysis through beta-3 adrenergic receptor-mediated pathways and inhibits lipogenesis. Unlike full GH, it does not bind to the GH receptor and does not stimulate IGF-1 production, insulin resistance, or cell proliferation. In a rabbit osteoarthritis model, intra-articular AOD-9604 enhanced cartilage regeneration and outperformed hyaluronic acid alone, suggesting effects on proteoglycan and collagen synthesis in cartilage.
Evidence Snapshot
Human Clinical Evidence
Moderate. Phase IIb clinical trial conducted but did not meet primary endpoint for obesity. Some positive secondary outcomes.
Animal / Preclinical
Moderate. Animal studies show fat reduction without growth effects. A rabbit OA study showed cartilage regeneration with intra-articular injection, outperforming hyaluronic acid.
Mechanistic Rationale
Moderate. The lipolytic fragment concept is sound but clinical translation has been challenging. Orthopaedic applications are emerging.
Research Gaps & Open Questions
What the current literature has not yet settled about AOD-9604:
- 01The Phase IIb obesity trial did not meet its primary endpoint — the central research gap is that there is no positive Phase III demonstration of meaningful weight loss in humans, and the mechanistic case for fat-specific lipolysis has not been reconciled with the negative clinical outcome.
- 02Why the preclinical-to-clinical translation failed — rodent and in vitro data supported the lipolytic-fragment mechanism; whether the failure in humans reflects dose, duration, species differences in beta-3 adrenergic signaling, or a fundamental mechanistic gap is unresolved.
- 03Osteoarthritis and cartilage-repair indications — the rabbit intra-articular study is interesting but is a single preclinical study; human OA data is absent, and the path from rabbit cartilage to clinical joint outcomes is long.
- 04Oral bioavailability — oral formulations exist and are marketed, but rigorous human pharmacokinetic comparison to subcutaneous administration is limited.
- 05Long-term safety beyond 12 weeks — the published clinical exposure duration is limited, and chronic-use safety surveillance in humans is not available.
- 06Combination with modern weight-loss therapeutics (GLP-1 agonists, tirzepatide-class dual agonists) — no head-to-head or combination data exists in the peptide's repositioned context.
Forms & Administration
AOD-9604 is administered via subcutaneous injection. Oral forms have also been explored. Protocols should be determined by a qualified clinician.
Dosing & Protocols
The ranges below reflect protocols commonly discussed in the literature and by clinicians — not a prescription. Actual dosing for any individual should be determined by a qualified healthcare provider who knows the patient.
Typical Range
Community protocols most commonly describe 300 mcg per subcutaneous injection, aligning with the doses used in the Metabolic Pharmaceuticals clinical program. Some protocols use 250–500 mcg. Oral formulations have been studied and are still marketed; oral bioavailability is low and the dose equivalence to subcutaneous is not rigorously established.
Frequency
Once-daily subcutaneous injection, typically in the morning or before the first meal, is the most commonly described cadence. The Phase IIb trial used 1 mg daily as one of its arms, and 0.25–1 mg daily as the general dose range. Injection is usually into abdominal subcutaneous fat.
Timing Considerations
No specific timing requirements: can be administered at any time of day, with or without food, and is not tied to exercise timing. Consistency matters more than the specific clock — dose at roughly the same time each day (or same day each week, for weekly protocols) to keep exposure steady.
Cycle Length
Community protocols commonly describe 8–12 week runs, which mirrors the Phase IIb trial's 12-week treatment window. Whether cycling versus continuous use matters for AOD-9604 is not established — the trial did not address this question.
Protocol Notes
AOD-9604 is supplied as a lyophilized powder reconstituted in bacteriostatic water. Subcutaneous injection via insulin syringe into abdominal fat is the most commonly used route, matching the clinical trial convention. Reconstituted peptide is generally stored refrigerated. The 'fat-burning' marketing and the Phase IIb data are in tension, and any clinician or user considering AOD-9604 should understand that the central weight-loss premise did not meet its primary endpoint in a properly powered randomized trial. Some users report subjective changes in body composition or appetite; these reports have to be weighed against the trial data, not used to override it. The safety signal in the Metabolic Pharmaceuticals program was relatively benign — that is arguably the most defensible basis for any continued interest in the molecule, not proven efficacy. Quality of research-chemical supply varies. Identity verification (correct 16-amino-acid sequence with tyrosine addition) is not pharmaceutical-grade in the peptide market.
These numbers describe what the published clinical program used and what is circulating in the community. AOD-9604 is not FDA-approved as a drug for any indication. Its GRAS status as a food additive does not constitute efficacy approval for weight loss. Any actual use should be under clinician guidance, with realistic expectations shaped by the Phase IIb data.
Timeline of Effects
Onset
In the published clinical program, measurable fat-mass changes (where observed in secondary outcomes) emerged over weeks, not days. Subjective reports of appetite change or perceived fat-loss effect within the first 1–2 weeks are common anecdotally but were not a primary trial finding.
Peak Effect
The Phase IIb trial ran 12 weeks. Where secondary-outcome changes appeared, they continued to accrue over the full treatment window. Published data does not characterize effects beyond 12 weeks.
After Discontinuation
AOD-9604 has a short plasma half-life. Any weight or body-composition effects attributable to the peptide would be expected to dissipate in the absence of sustained lifestyle changes. The trial did not publish extensive post-treatment follow-up characterizing rebound.
Common Questions
Who AOD-9604 Is NOT For
- •Pregnancy and breastfeeding — no human pregnancy or lactation safety data.
- •Pediatric use (under 18) — no data and no appropriate indication.
- •Known hypersensitivity to peptide therapeutics, growth hormone products, or excipients used in compounded or reconstituted preparations.
- •Active malignancy — the theoretical concern is weaker than for IGF-1 analogues (AOD-9604 does not measurably elevate IGF-1 in published studies), but the absence of long-term carcinogenicity data in humans and the GH-fragment origin warrant caution in active cancer.
- •Untreated thyroid disease — lipid metabolism interactions may confound interpretation of thyroid-driven metabolic changes.
- •Patients with unrealistic weight-loss expectations — this is a practical rather than medical contraindication, but given the Phase IIb result, framing AOD-9604 as a standalone fat-loss solution is not clinically honest.
Drug & Supplement Interactions
No significant human drug-drug interaction signals were published from the Metabolic Pharmaceuticals clinical program, but interaction data is limited and clinical pharmacology characterization is not at the depth of approved drugs. The mechanism claim — that AOD-9604 does not meaningfully elevate IGF-1, insulin resistance, or GH-axis hormones — was supported in the company's published data, which if accurate would limit the interaction profile compared with full GH or GH secretagogues. Combining AOD-9604 with GH, GH secretagogues (sermorelin, tesamorelin, CJC-1295, ipamorelin), MK-677, or IGF-1 analogues compounds the broader metabolic and growth-factor load; the specific interactions are not characterized. Concurrent use with GLP-1 receptor agonists, SGLT2 inhibitors, or other metabolic weight-loss agents has not been systematically studied. Patients on thyroid replacement, beta-blockers, or anti-diabetic medications should disclose AOD-9604 use to prescribing clinicians. Anabolic-androgenic steroids do not directly interact with the proposed AOD-9604 mechanism.
Safety Profile
Common Side Effects
Cautions
- • Not FDA-approved as a drug
- • Clinical trial results for obesity were not conclusive enough for drug approval
- • Quality varies between sources
What We Don't Know
The Phase IIb clinical trial for obesity did not meet its primary endpoint, which raises questions about efficacy at studied doses.
Legal Status
United States
AOD-9604 is not FDA-approved as a drug for any therapeutic indication. It received GRAS (Generally Recognized as Safe) status as a food-additive ingredient — a food-regulatory category that does not evaluate efficacy and does not authorize marketing of the substance as a treatment for obesity, joint disease, or any medical condition. In 2023, FDA guidance narrowed 503A compounding access for several peptides; AOD-9604's compounding status is subject to that evolving regulatory posture. Research-chemical sales labeled 'not for human use' remain common.
International
Australia's TGA has an extended regulatory history with AOD-9604 given Metabolic Pharmaceuticals' Australian origin; it is not registered as a medicine. The EMA has not authorized AOD-9604 as a medicine; the UK MHRA has not licensed it. Canada and most EU member states treat it as an unapproved investigational agent.
Sports & Competition
Prohibited at all times under WADA category S2 (peptide hormones, growth factors, and related substances and mimetics). The 'GH fragment' positioning is precisely what puts it in this category. Athletes subject to WADA, USADA, UKAD, or equivalent frameworks should treat AOD-9604 as prohibited in and out of competition.
Regulatory status changes over time. Verify current local rules with a qualified professional.
Myths & Misconceptions
Myth
AOD-9604 is a proven fat-loss peptide.
Reality
The Phase IIb obesity trial did not meet its primary weight-loss endpoint versus placebo. That is the most important single fact about AOD-9604, and most consumer-facing marketing does not mention it. Some secondary outcomes were positive, but the regulatory program did not advance and the drug was not approved for obesity.
Myth
AOD-9604 is FDA-approved because it has GRAS status.
Reality
GRAS status is a food-additive classification, not a drug approval. It does not evaluate efficacy and does not authorize marketing the substance as a treatment for any medical condition. Conflating GRAS with FDA drug approval is a common and misleading marketing shortcut.
Myth
AOD-9604 gives you the fat-loss benefits of growth hormone without any of the side effects.
Reality
The published data does suggest AOD-9604 does not meaningfully elevate IGF-1 or cause insulin resistance at studied doses — which is a real advantage over full GH in those specific dimensions. But the weight-loss 'benefit' of GH is itself modest and context-dependent, and the Phase IIb trial showed that isolating a 'lipolytic domain' did not translate into clinically meaningful weight loss. Side effects avoided do not equal benefits delivered.
Myth
AOD-9604 works well when stacked with GH secretagogues to enhance fat loss.
Reality
Stacking claims are not supported by controlled human studies. Combining AOD-9604 with agents that do elevate IGF-1 (GH, secretagogues, MK-677) erodes the mechanistic rationale that made AOD-9604 attractive in the first place — namely that it was supposed to be the fat-loss part without the IGF-1 elevation.
Published Research
9 studiesSafety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance
Therapeutic Peptides in Orthopaedics: Applications, Challenges, and Future Directions
Effect of Intra-articular Injection of AOD9604 with or without Hyaluronic Acid in Rabbit Osteoarthritis Model
AOD-9604 does not influence the WADA hGH isoform immunoassay
AOD-9604 Metabolic
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.
Increase of fat oxidation and weight loss in obese mice caused by chronic treatment with human growth hormone or a modified C-terminal fragment.
Metabolic studies of a synthetic lipolytic domain (AOD9604) of human growth hormone
Effects of oral administration of a synthetic fragment of human growth hormone on lipid metabolism.
Quick Facts
- Class
- GH Fragment
- Tier
- C
- Evidence
- Emerging
- Safety
- Moderate Data
- Updated
- May 2026
- Citations
- 9PubMed
Also known as
Tags
Related Goals
Evidence Score
Clinical Trials
View Clinical TrialsLinks to ClinicalTrials.gov for reference. Listing does not imply endorsement.