AOD-9604: Growth Hormone C-Terminal Fragment Research Overview

AOD-9604 was developed by researchers at Monash University and Metabolic Pharmaceuticals in the 1990s. The compound is based on residues 177-191 of human growth hormone (hGH) — the C-terminal region that early research had identified as carrying lipolytic activity distinct from the growth-stimulating activity of the full peptide.^[1]

The peptide includes a tyrosine residue added to the N-terminus of the hGH(177-191) fragment, both for synthetic accessibility and for enhanced stability in research preparations. The full sequence is sometimes designated Tyr-hGH(177-191).^[2]

AOD-9604 is studied as a research reference compound in preclinical lipid metabolism and growth hormone fragment biology. It has not been approved by the FDA for any human therapeutic or medical purpose.

AOD-9604 structural features:

• Sequence: Tyr-Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Glu-Gly-Ser-Cys-Gly-Phe (16 amino acids: Tyr added to native hGH 177-191)

• Native parent region: hGH 177-191

• N-terminal modification: tyrosine residue

• Disulfide bond: one (between the two cysteine residues at positions 7 and 14 of AOD-9604)

• Molecular formula: C₇₈H₁₂₃N₂₃O₂₃S₂

• Molecular weight: approximately 1,815 Da

Early research with hGH fragments established that the C-terminal region carries lipolytic signaling without the IGF-1-mediated growth effects of full GH. The 177-191 fragment was identified as the minimal active sequence for this lipolytic activity, and Tyr-hGH(177-191) became the canonical research peptide for studying GH C-terminal fragment biology.^[1]

The disulfide bond between the two cysteines is essential for the peptide's three-dimensional structure and its biological activity. Maintaining the correct disulfide pairing is therefore important during synthesis and storage.

AOD-9604's research-characterized mechanisms focus on lipid metabolism pathways.

Cell-based studies in adipocyte preparations have characterized AOD-9604 effects on triglyceride hydrolysis. The compound has been associated with increased lipolysis through pathways downstream of the GH C-terminal signaling region, distinct from the growth hormone receptor-mediated effects of full GH.^[3]

Unlike full GH, AOD-9604 does not engage the GH receptor productively. The exact receptor(s) mediating its effects in cell-based preparations have remained an active area of research, with some studies suggesting beta-3 adrenergic receptor cross-talk or distinct uncharacterized receptors.^[4]

AOD-9604 research is concentrated in metabolic and adipose tissue preclinical studies.

Cultured adipocytes (3T3-L1 cell line and primary adipocytes) are standard substrates for AOD-9604 research. Endpoints include glycerol release, triglyceride content measurement, and lipase enzyme activity.^[3]

Rodent models of diet-induced obesity have included AOD-9604 in experimental arms examining body composition endpoints, adipose tissue mass, and metabolic markers.^[4]

A secondary research line has examined AOD-9604 effects in cartilage and joint tissue preclinical models, possibly mediated by separate pathways than the lipolytic activity.^[5]

AOD-9604's disulfide bond requires careful handling to maintain integrity.

Lyophilized AOD-9604 is stored at minus 20 degrees Celsius. The disulfide-containing structure is sensitive to repeated freeze-thaw and to reducing conditions.

Bacteriostatic water is the standard reconstitution solvent. Care should be taken to avoid reducing agents in the reconstitution buffer.

HPLC for purity, mass spectrometry for identity confirmation, and verification of correct disulfide pairing by reduced/oxidized peptide mapping. Each batch of Instant Peptides AOD-9604 ships with a full Certificate of Analysis.

Instant Peptides supplies AOD-9604 as a synthetic lyophilized reference compound. Material is supplied to qualified research professionals. Not for human or animal consumption.

View the product page for current pricing and the Certificate of Analysis for the active batch.