AOD9604 is a modified peptide fragment derived from the C-terminal region of human growth hormone (hGH), specifically amino acids 177–191. Developed in the late 1990s by Metabolic Pharmaceuticals, AOD9604 was engineered to retain the lipolytic (fat-mobilizing) properties of growth hormone while eliminating its proliferative and IGF-1–mediated effects. For Canadian research laboratories investigating metabolic and adipose tissue biology, AOD9604 represents a compelling tool for studying isolated lipolytic pathways.
All information in this guide is provided for research purposes only. AOD9604 is not approved for human consumption or therapeutic use.
What Is AOD9604?
AOD9604 (sometimes referred to as hGH fragment 177-191 or Advanced Obesity Drug) is a 15-amino acid peptide with the sequence H-Tyr-Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Glu-Gly-Ser-Cys-Gly-Phe-OH, incorporating a tyrosine residue added to the N-terminus of the native hGH 177–191 fragment to improve stability.
The rationale behind AOD9604’s design is grounded in decades of endocrinology research. The 177–191 region of growth hormone was identified as the minimal sequence required to stimulate lipolysis and inhibit lipogenesis in adipocytes — without triggering the downstream signaling cascades associated with full-length hGH, particularly IGF-1 production and cell proliferation.
Mechanism of Action
Lipolytic Signaling
AOD9604 activates lipolysis through mechanisms that overlap with, but are distinct from, full-length growth hormone. Key findings from preclinical research include:
- Beta-adrenergic receptor pathway activation: AOD9604 has been shown to increase cyclic AMP (cAMP) levels in adipocytes, upregulating hormone-sensitive lipase (HSL) and promoting triglyceride hydrolysis.
- Inhibition of lipogenesis: The peptide reduces the expression of lipogenic enzymes, effectively decreasing de novo fatty acid synthesis in hepatocytes and adipocytes.
- Stimulation of free fatty acid (FFA) release: In vitro studies demonstrate increased FFA efflux from isolated adipose tissue preparations treated with AOD9604.
IGF-1 Independence
A critical distinction between AOD9604 and full-length hGH is the absence of IGF-1 upregulation. Research by Heffernan et al. (2001) confirmed that AOD9604 does not increase serum IGF-1 levels in animal models, even at doses that produce measurable lipolytic effects. This property makes AOD9604 a valuable research tool for disentangling hGH’s metabolic effects from its mitogenic actions.
Key Research Studies
Preclinical Evidence
The foundational preclinical work on AOD9604 was conducted at Monash University in Australia. Key studies include:
- Adipocyte culture models: AOD9604 stimulated lipolysis in isolated rat adipocytes at concentrations comparable to hGH, with an EC50 in the nanomolar range.
- Obese rodent models: Chronic administration in diet-induced obese mice reduced body weight and visceral fat mass without altering lean tissue, glucose tolerance, or serum IGF-1.
- Acute lipolysis assays: Dose-dependent increases in glycerol and FFA release from isolated fat pads were observed within 2–4 hours of peptide exposure.
Human Clinical Trials
Metabolic Pharmaceuticals advanced AOD9604 through multiple Phase II clinical trials:
- Phase IIb trial (n=~300): Over 12 weeks, subjects receiving daily oral AOD9604 demonstrated statistically significant reductions in body weight compared to placebo. However, the magnitude of effect was modest (~1.5–2 kg), and the trial did not meet all primary endpoints to the satisfaction of regulatory authorities.
- Safety data: Across all clinical trials, AOD9604 was well tolerated. No clinically significant changes in IGF-1, glucose metabolism, or thyroid function were observed. Adverse events were comparable to placebo.
Despite the mixed clinical outcomes, AOD9604 remains scientifically relevant for researchers studying the mechanistic basis of hGH-mediated lipolysis.
Research Protocols
Reconstitution and Handling
For laboratory use, AOD9604 is typically supplied as a lyophilized powder in vials of 5 mg. Recommended reconstitution procedure:
1. Allow the vial to reach room temperature before reconstitution.
2. Reconstitute with sterile bacteriostatic water (typically 2 mL for a 5 mg vial, yielding a 2.5 mg/mL concentration).
3. Gently swirl — do not vortex — to minimize peptide degradation.
4. Store reconstituted solution at 2–8°C and use within 14 days.
Use our peptide calculator to determine precise concentration and volumetric dosing for your research applications.
In Vitro Research Concentrations
Published studies have utilized AOD9604 concentrations ranging from 10 nM to 10 μM in cell culture systems. A suggested starting point for adipocyte lipolysis assays:
- Adipocyte culture: 1–10 μM for acute lipolysis assays (2–4 hour incubation)
- Hepatocyte lipogenesis inhibition: 100 nM – 1 μM
- Signal transduction studies: 10–100 nM for receptor-level investigations
In Vivo Research Dosing (Animal Models)
Preclinical literature reports the following ranges in rodent models:
- Acute lipolysis studies: 0.1–1 mg/kg subcutaneous injection
- Chronic metabolic studies: 0.25–1 mg/kg/day subcutaneous injection over 4–12 weeks
These values are provided for reference based on published literature. All in vivo research must comply with institutional animal care and ethics guidelines.
Safety and Regulatory Considerations
Research-Only Status
AOD9604 is classified as a research peptide. It has not been approved by Health Canada, the FDA, or any regulatory authority for therapeutic or cosmetic use. All products sold by Webber Science are explicitly labeled for research purposes only and are not for human consumption.
Reported Adverse Events in Clinical Literature
In the Phase II human trials, the most commonly reported adverse events were mild and included:
- Injection site reactions (oral formulation studies reported minimal GI effects)
- Headache
- Fatigue
No serious adverse events were attributed to AOD9604 in any trial. Importantly, no changes in glucose homeostasis, IGF-1 levels, or thyroid panels were observed — consistent with the peptide’s mechanism of action.
Canadian Regulatory Notes
Canadian researchers should be aware that AOD9604 is not listed on Health Canada’s Controlled Substances schedule, but it falls under the general provisions of the Food and Drugs Act regarding investigational compounds. Laboratories must maintain appropriate documentation and ensure that research use declarations are on file.
AOD9604 vs. Related Peptides
AOD9604 vs. HGH Fragment 176-191
AOD9604 and HGH Fragment 176-191 share a common origin — both are derived from the C-terminal lipolytic region of growth hormone. The key difference is that AOD9604 incorporates a tyrosine residue at the N-terminus (fragment 177–191 + Tyr) and was specifically modified for oral bioavailability during pharmaceutical development. Both peptides demonstrate lipolytic activity without IGF-1 upregulation, but their pharmacokinetic profiles differ due to structural modifications.
AOD9604 vs. GLP-1 Agonists
For researchers exploring broader metabolic pathways, our retatrutide vs semaglutide vs tirzepatide comparison guide covers the GLP-1/GIP/glucagon receptor agonist class — a distinct mechanism from AOD9604’s hGH fragment–derived lipolysis. Whereas GLP-1 agonists primarily reduce appetite and improve glycemic control, AOD9604 acts directly on adipose tissue lipolytic pathways. These complementary mechanisms make both classes relevant for comparative metabolic research.
Frequently Asked Questions
What is the difference between AOD9604 and full-length growth hormone?
AOD9604 is a 15-amino acid fragment corresponding to the C-terminal lipolytic region of hGH (amino acids 177–191, with an added tyrosine). Unlike full-length hGH, AOD9604 does not increase IGF-1 production, does not stimulate cell proliferation, and does not affect glucose metabolism. It retains only the fat-mobilizing properties of hGH.
Is AOD9604 orally bioavailable?
One of the original development goals for AOD9604 was oral delivery. Phase II clinical trials used an oral formulation with demonstrated systemic absorption. However, oral bioavailability is lower than subcutaneous injection, and most current research uses injectable formulations for greater dose control and reproducibility.
Can AOD9604 be used for weight loss?
AOD9604 is available for research purposes only and is not approved for weight loss or any therapeutic application. Clinical trials showed modest reductions in body weight that did not meet regulatory thresholds for efficacy. Researchers should approach AOD9604 as a mechanistic tool for studying lipolytic signaling, not as a weight-loss intervention.
How should AOD9604 be stored?
Lyophilized AOD9604 should be stored at –20°C for long-term storage. Once reconstituted with bacteriostatic water, the solution should be stored at 2–8°C and used within 14 days. Avoid repeated freeze-thaw cycles.
Where can Canadian researchers source AOD9604?
Webber Science supplies AOD9604 as a research-grade peptide for laboratory use. View AOD9604 5mg product page for specifications, COA availability, and ordering information.
Summary
AOD9604 occupies a unique niche in peptide research: it is one of the few well-characterized compounds that isolates the lipolytic action of growth hormone from its broader endocrine effects. For Canadian laboratories studying adipose tissue biology, metabolic signaling, or comparative lipolytic mechanisms, AOD9604 provides a precise pharmacological tool with an established preclinical and clinical evidence base.
Key takeaways:
- AOD9604 is the hGH 177–191 fragment with an added tyrosine residue, designed for lipolytic specificity
- It activates lipolysis without increasing IGF-1, distinguishing it from full-length hGH
- Clinical trials demonstrated safety but modest efficacy, underscoring its value as a research tool rather than a therapeutic
- Available in 5 mg vials from Webber Science for qualified research laboratories
All products are sold for research purposes only. Not for human consumption or therapeutic use.
For broader context on metabolic and anti-obesity peptide research, explore our comprehensive weight loss peptides guide and peptide calculator for dosing and reconstitution calculations.