AOD-9604 Research:
HGH Fragment 176-191 & Fat Metabolism
AOD-9604 is a synthetic analogue of the C-terminal fragment (residues 176–191) of human growth hormone. It mimics the lipolytic activity of hGH without activating IGF-1 or the GH receptor — making it a selective tool for fat metabolism and metabolic research.
What Is AOD-9604?
AOD-9604 (Anti-Obesity Drug 9604) is a stabilized synthetic analogue of the hGH C-terminal fragment spanning residues 176–191 (Tyr-Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Glu-Gly-Ser-Cys-Gly-Phe), with a disulfide bridge between Cys₁₈₂ and Cys₁₈₉ for structural stabilization. Developed initially by Monash University researchers, AOD-9604 was designed to isolate the lipolytic (fat-burning) activity of full-length hGH from its IGF-1-stimulating and anabolic growth-promoting activities.
Unlike full hGH, AOD-9604 does not bind to the GH receptor (GHR) or activate IGF-1 signaling pathways. It instead activates a distinct receptor (proposed to involve β3-adrenergic receptor interactions and hypothalamic melanocortin pathways) to stimulate lipolysis in adipocytes while inhibiting lipogenesis. Lumen Peppers provides research-grade AOD-9604 for in vitro and preclinical laboratory investigation only.
Key Research Findings
AOD-9604 research spans lipolysis mechanisms, adipocyte biology, metabolic homeostasis, and selective fat metabolism modulation.
Lipolysis in Adipocyte Models
AOD-9604 stimulates lipolysis in 3T3-L1 adipocytes and isolated primary rat adipocytes, increasing glycerol and free fatty acid release comparable to full-length hGH at equivalent molar concentrations. Lipolytic activity is concentration-dependent and inhibitable by β-blocker pretreatment in some models.
GHR-Independent Mechanism
AOD-9604 does not compete with hGH for GHR binding and does not activate the JAK2-STAT5 pathway — the primary hGH anabolic signaling cascade. This receptor-independent selectivity makes it a pharmacological tool for isolating fat metabolism effects from hGH's anabolic, anti-aging, and IGF-1-driven activities.
Obesity Model Studies
In obese mouse and rat models (HFD and ob/ob), chronic AOD-9604 administration reduces body fat mass without significantly altering lean muscle mass, food intake, or IGF-1 levels. These studies establish AOD-9604 as a research tool for selective adiposity reduction without anabolic confounds.
Cartilage & Tissue Research
Beyond fat metabolism, AOD-9604 has been studied for chondroprotective and cartilage regeneration properties. In vitro chondrocyte studies and in vivo OA models suggest AOD-9604 may have activity at cartilage matrix synthesis and degradation balance — an area of active investigation.
Safety Profile Research
Multiple Phase I and Phase II clinical trials established that AOD-9604 does not affect glucose metabolism, insulin sensitivity, or IGF-1 levels at studied doses — confirming the GHR-independent selectivity seen in preclinical models. This pharmacological dissociation is a key research tool property.
Receptor Characterization
The exact receptor target of AOD-9604 remains under investigation. Research suggests involvement of β-adrenergic receptors, hypothalamic melanocortin circuits, and possibly a novel hGH fragment receptor distinct from canonical GHR — making AOD-9604 a valuable probe for receptor pharmacology studies.
Proposed Mechanisms of Action
Proposed model: AOD-9604 activates β3-adrenergic receptors (β3-AR) on adipocyte cell surfaces, increasing intracellular cAMP via Gs-adenylyl cyclase coupling. Elevated cAMP activates PKA, which phosphorylates hormone-sensitive lipase (HSL) and perilipin-1, enabling triglyceride hydrolysis and free fatty acid release.
AOD-9604 inhibits de novo lipogenesis in adipocytes, reducing acetyl-CoA carboxylase (ACC) activity and suppressing fatty acid synthase (FAS) gene expression. This dual lipolysis stimulation + lipogenesis inhibition profile produces net fat mobilization in adipose tissue models.
AOD-9604 does not activate JAK2/STAT5, MAPK/ERK, or PI3K/Akt — the classic GHR signaling cascades. This selectivity suggests a distinct receptor engagement mechanism. Studies using β-blocker pretreatment partially attenuate AOD-9604's lipolytic effects, implicating adrenergic pathways as part of the mechanism.
Emerging research suggests AOD-9604 interacts with hypothalamic melanocortin circuits (MC3R/MC4R on arcuate nucleus neurons), potentially modulating central fat storage signaling downstream of leptin and POMC pathways. This central mechanism may complement direct adipocyte lipolysis effects.
In chondrocyte models, AOD-9604 upregulates collagen II and aggrecan synthesis while reducing MMP-13 (collagenase-3) expression — suggesting an anabolic/anti-catabolic effect on cartilage ECM distinct from its fat metabolism activity and not mediated through classical GHR-IGF-1 signaling.
Active Research Applications
Adipocyte Lipolysis
3T3-L1 and primary adipocyte lipolysis assays measuring glycerol/FFA release, HSL phosphorylation, and lipid droplet dynamics.
Obesity & Metabolic Models
HFD and ob/ob mouse body composition studies — fat mass, lean mass, and metabolic parameter tracking without IGF-1 confounds.
Cartilage & OA Research
Chondrocyte ECM synthesis/degradation studies and in vivo OA models studying AOD-9604 chondroprotective activity.
Receptor Pharmacology
β3-AR binding studies, cAMP reporter assays, and GHR competition assays characterizing AOD-9604's novel receptor pharmacology.
GH Fragment Biology
Comparative studies of full hGH vs. AOD-9604 vs. other GH fragments to map structure-activity relationships in fat metabolism.
Anti-Obesity Drug Research
Reference compound for developing selective lipolytic agents that dissociate fat metabolism from anabolic/IGF-1 growth hormone effects.
Protocol Notes for Researchers
Related Research Compounds
AOD-9604 — Research Grade ≥99%
Research-grade purity ≥99% · Third-party HPLC verified · Ships from the U.S.
All products sold by Lumen Peppers are intended exclusively for in vitro laboratory research and investigative purposes. These compounds are not approved by the FDA for human or veterinary use. They are not drugs, supplements, or medications. Lumen Peppers makes no therapeutic claims. Researchers are solely responsible for ensuring compliance with all applicable laws and regulations in their jurisdiction.