HGH Fragment 176-191

What it is

HGH Fragment 176-191 is a synthetic 16-amino-acid peptide corresponding to the C-terminal fragment of human growth hormone (residues 176–191). The peptide is essentially identical to AOD-9604 in core sequence, with minor differences in N-terminal modification.

The molecule was developed on the same hypothesis as AOD-9604: that the fat-metabolism effects of growth hormone could be isolated in the C-terminal fragment without the growth-promoting and metabolic effects of the full-length hormone. HGH Fragment 176-191 has accumulated less formal clinical research than AOD-9604. HGH Fragment 176-191 is not FDA-approved for any use in the United States.

Mechanism of action

Proposed mechanisms come from laboratory and animal research. The hypothesized mechanism is the same as for AOD-9604: stimulation of lipolysis through β3-adrenergic receptor pathways, without binding the GH receptor and without elevating IGF-1. Published research has not reported the typical GH-related effects on glucose metabolism, IGF-1, or insulin sensitivity, but human data are very limited.

Clinical evidence

The clinical evidence base for HGH Fragment 176-191 specifically is limited. Much of what is written about it is extrapolated from research on AOD-9604, on the assumption that the closely related peptides behave similarly; this assumption has not been tested directly. Well-controlled human trials establishing the effectiveness and safety of HGH Fragment 176-191 are lacking.

Why we don’t prescribe it at The Tide

The Tide does not prescribe HGH Fragment 176-191. Independent clinical trial data on this specific peptide are sparse, and its effectiveness and safety in people have not been established.

Side effects and contraindications

Human safety has not been established in well-controlled trials, and long-term effects are unknown. Products sold outside regulated channels (e.g., “research peptides”) may vary in purity, dose, and sterility. Avoided in pregnancy and breastfeeding.