Fragment 176-191

In simple words

Fragment 176-191 is a small piece of the growth hormone molecule that is responsible for breaking down fat but does not affect growth or blood sugar. It was studied as a weight-loss agent, but a large human study showed no effect.

What this molecule is

16 amino acids: Tyr-Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Gly-Ser-Cys-Gly-Phe-Thr. C-terminal fragment of hGH (positions 176-191). ~1817 Da.

Why it is studied

A lipolytic fragment of growth hormone without growth-promoting or diabetogenic effects. Stimulates β-adrenergic lipolysis. A Phase 2b trial (536 people) did not show significant superiority over placebo — development as a weight-loss drug was halted in 2007. Used off-label as an add-on to GLP-1.

How it works

↑β3-adrenergic receptors in adipose tissue → ↑hormone-sensitive lipase → ↑lipolysis. Inhibits acetyl-CoA carboxylase → ↓de novo lipogenesis. Does not affect GH receptors, does not stimulate IGF-1, does not disrupt glycemia.

Doses used in studies

In research practice, 250–300 mcg SC in the morning on an empty stomach was used, in courses of 8–12 weeks. Not clinically validated.

Combined with in studies

• CJC-1295/Mod-GRF — different mechanisms: GHRH + β3-AR
• L-Carnitine — lipolysis + β-oxidation
• 5-Amino-1MQ — NNMT + β3-AR

Level of evidence

Level B-C Human observational data. There are studies in humans, but they are small, uncontrolled, or cohort studies. The data are encouraging but need confirmation. one human study (oral). Mostly animal data.

Important to know

Honest caveat: Phase 2b failed (536 people, 2007). WADA ban S0 (2022). Almost no clinical data. Research only.

Studies in PubMed

1. AOD-9604 Metabolic. (Curr Opin Investig Drugs, 2004)
2. The effects of human GH and its lipolytic fragment (AOD9604) on lipid metabolism following chronic treatment in obese mice and beta(3)-AR knock-out mice. (Endocrinology, 2001)
3. Increase of fat oxidation and weight loss in obese mice caused by chronic treatment with human growth hormone or a modified C-terminal fragment. (Int J Obes Relat Metab Disord, 2001)
4. Effects of oral administration of a synthetic fragment of human growth hormone on lipid metabolism. (Am J Physiol Endocrinol Metab, 2000)
5. Effect of Intra-articular Injection of AOD9604 with or without Hyaluronic Acid in Rabbit Osteoarthritis Model. (Ann Clin Lab Sci, 2015)
6. Detection and in vitro metabolism of AOD9604. (Drug Test Anal, 2015)