HGH Fragment 176–191

A short synthetic piece cut from the tail end (residues 176–191) of human growth hormone. Researchers isolated this region as a candidate fat-breakdown domain without growth hormone's other effects.

Full-length growth hormone breaks down fat but also raises IGF-1 and blood sugar. In mouse studies, the modified fragment AOD-9604 increased fat oxidation without binding the growth hormone receptor, stimulating growth or raising blood sugar. Whether the unmodified 176–191 fragment behaves the same way has not been shown.

No published human studies of this exact fragment were found. The fat-breakdown research usually credited to it was done mostly on AOD-9604, which differs only in its first amino acid. In obese rats and mice, AOD-9604 reduced weight gain and increased fat oxidation, an effect lost in mice lacking the beta-3 adrenergic receptor. In humans, AOD-9604 missed its weight-loss endpoint in a 502-person phase 2b trial and development stopped in 2007. Human pharmacokinetics, efficacy and safety of the unmodified fragment are unknown.

No human safety data exists for this fragment. FDA's review of the closely related AOD-9604 noted equivocal genotoxicity results, a liver signal in monkeys, bone-marker changes in rats and immunogenicity concerns for injectable peptides. The unclear identity data and IU units raise the risk of measurement errors.

Not FDA-approved for any use. It is not in any FDA 503A category and has no USP monograph, so it has no lawful compounding route. WADA names 'hGH 176–191' explicitly under S2.2.3, prohibited at all times. Status as of October 2026.