Body Composition · Metabolic
HGH Fragment 176-191
Also known as: hGH 176-191, Frag 176-191, Tyr-hGH(177-191)
A C-terminal fragment of human growth hormone investigated as a lipolytic agent and closely related to AOD-9604, with similarly disappointing clinical trial results in obesity.
Sign in to add to watchlistEvidence strength
Strength of human clinical evidence — A (strongest) to D (mostly preclinical). This reflects research maturity, not safety or suitability.
Vial Theory provides educational research summaries only. Content is not medical advice, diagnosis, treatment, dosing guidance, or individualized suitability screening. Regulatory status can change over time and varies by jurisdiction.
Key Takeaways
- ›HGH Fragment 176-191 is a fat-loss fragment of growth hormone, essentially the same active molecule as AOD-9604.
- ›Human weight-loss evidence (via AOD-9604) was negative; benefits rest mostly on cell and animal studies.
- ›It is not approved for any use and is sold mainly through compounding and gray-market channels.
- ›Long-term safety in humans is not established, and product identity/quality can vary.
- ›Marketing outpaces the evidence. Speak with a licensed healthcare professional before health decisions.
What It Is
HGH Fragment 176-191 is a synthetic peptide corresponding to amino acids 176 to 191 of the C-terminal region of human growth hormone. The fragment was studied as part of the same research program that produced AOD-9604, which adds a single N-terminal tyrosine residue to the same core sequence for stability and analytical reasons. The two compounds are often discussed interchangeably in informal contexts, though the published clinical trial program in obesity used AOD-9604 rather than the 176-191 fragment specifically.
Mechanistically, the fragment was proposed to retain the lipolytic activity of full-length growth hormone — through stimulation of fat-cell lipolysis and possible inhibition of lipogenesis — without the growth-promoting, glucose-altering, or IGF-1-elevating effects of the parent molecule. This dissociation hypothesis has been the central pharmacological rationale for both compounds.
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Disclaimer: This content is for educational and research purposes only and is not medical advice. Always consult a licensed healthcare professional before making health-related decisions.