HGH Fragment 176-191
The unmodified C-terminal fragment of human growth hormone, comprising exactly the last 16 amino acids (176-191) of the full 191-amino-acid GH molecule. The predecessor to AOD-9604, retaining the lipolytic (fat-metabolizing) properties of growth hormone without its anabolic, growth-promoting, or insulin-antagonistic effects. Less stable than AOD-9604 due to lacking the additional tyrosine residue.
Typical Dosage
Research: 250-500 mcg subcutaneous once or twice daily, on an empty stomach. Often cycled 8-12 weeks on, 4 weeks off. The short half-life typically requires twice-daily dosing for sustained effect.
Administration
Subcutaneous injection
Mechanism of Action
HGH Fragment 176-191 is the unmodified C-terminal segment of human growth hormone, representing exactly the last 16 amino acids of the 191-amino-acid GH molecule. Research identified this region as containing the molecular determinants responsible for GH's lipolytic activity, independent of the N-terminal domain that binds the growth hormone receptor and drives IGF-1 production and tissue growth.
The fragment activates lipolysis in white adipose tissue through interaction with beta-adrenergic signaling pathways. This triggers the cAMP/protein kinase A cascade that phosphorylates and activates hormone-sensitive lipase and perilipin proteins on the surface of lipid droplets within fat cells. The result is the breakdown of stored triglycerides into free fatty acids and glycerol, which are released into circulation for oxidation by energy-demanding tissues such as skeletal muscle and the liver.
Because the fragment lacks the binding regions for the GH receptor (located in amino acids 1-175), it does not activate the JAK2-STAT5 signaling pathway responsible for hepatic IGF-1 synthesis, somatic growth, or the insulin-antagonistic effects of full-length growth hormone. However, the shorter half-life compared to AOD-9604 (which has an additional stabilizing tyrosine residue) means more frequent dosing is required, and clinical evidence supporting its efficacy in humans remains very limited.
Regulatory Status
Not FDA approved. Research compound only. Available through peptide suppliers.
Risks & Safety
Common: injection site irritation, headache, transient lightheadedness. Serious: unknown long-term effects due to extremely limited clinical data. Rare: hypersensitivity reactions. Shorter half-life than AOD-9604 makes dosing less practical. Not FDA approved.
Research Papers
No research papers indexed yet. Papers are fetched from PubMed weekly.
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