Trinity compound research profile
HGH Fragment 176-191
HGH Fragment 176-191 (drug code AOD9604) is a small lab-made piece — just 16 amino acids — cut from the tail end of the full growth hormone molecule, with...
Research overview
HGH Fragment 176-191 (drug code AOD9604) is a small lab-made piece — just 16 amino acids — cut from the tail end of the full growth hormone molecule, with one small chemical swap. The idea behind it: growth hormone's tail end seems responsible for burning fat, while the rest of the molecule causes the growth-related and blood-sugar effects. So scientists made just the tail piece, hoping to get the fat-burning benefit without the other effects (PubChem).
Mechanism under study
Unlike full growth hormone, this fragment does NOT attach to the regular growth hormone receptor and does NOT raise IGF-1 levels. Instead, animal research suggests it works through a different "switch" on fat cells called the beta-3 adrenergic receptor, encouraging fat cells to break down stored fat and burn it for energy, without needing to boost growth-related hormones (Heffernan et al. 2001).
Human evidence summary
This peptide actually went through a large, serious drug-development program — about 925 patients across six randomized, placebo-controlled trials between 2001 and 2007, including two big studies (300 and 500 obese adults) testing an oral pill version. The good news: it was very safe — no effect on blood sugar, no allergic reactions, and side effects similar to a placebo (fake pill) (Stier et al. 2013). The bad news: it simply did not work — the studies failed to show it actually caused meaningful weight loss, and the company stopped developing it as a drug in 2007 (FDA docket; Wikipedia background). This is an important, well-documented negative result, not just a lack of evidence.
Preclinical evidence summary
In mouse studies (including obese mice), giving this peptide or full growth hormone increased fat burning and reduced body weight (Heffernan et al., Int J Obes 2001). Safety testing in rats and monkeys found no concerning effects even at high doses, and no signs of the peptide causing genetic damage (nonclinical review). So the fat-burning effect and safety were both supported in animals — the disappointment came only when it was tested carefully in humans.
Source material
Use the linked publications and records to evaluate study design, population, limitations, and relevance.