HGH Fragment 176-191

HGH Fragment 176-191 is a synthetic peptide corresponding to amino acids 176 through 191 at the C-terminus of the human growth hormone molecule — the specific region responsible for growth hormone's fat-metabolising activity. Also studied under the designation AOD-9604, it was developed on the premise that this single functional domain could be isolated from the rest of the hormone.

Mechanism

Research indicates the fragment stimulates lipolysis in adipose tissue and inhibits lipogenesis, reproducing the metabolic effect of intact growth hormone on fat stores. Because the sequence excludes the domains that bind the growth hormone receptor's growth-promoting and glucoregulatory pathways, it does not raise IGF-1, does not stimulate skeletal or soft tissue growth, and has not been shown to affect insulin sensitivity or blood glucose in study conditions. This separation of effects is the entire reason the fragment is of interest.

What the research shows

• Increased lipolytic activity and fat oxidation in adipose tissue models
• Reduced adipogenesis and lipid accumulation in fat cell studies
• No measurable elevation of IGF-1 or growth-promoting activity, unlike full-length growth hormone
• No adverse effect on glucose tolerance or insulin sensitivity in study conditions
• Favourable safety and tolerability profile across obesity research programmes
• Additional interest in cartilage regeneration and joint tissue repair research

The fragment is studied as a targeted metabolic tool: the fat-mobilising action of growth hormone, isolated from its systemic effects.