Hexarelin

Hexarelin (examorelin) is a synthetic six-amino-acid peptide (His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2) in the growth hormone-releasing peptide (GHRP) family. It was made in Milan in the early 1990s as a more chemically stable analogue of GHRP-6, and in rats it released growth hormone (GH) at least as strongly as GHRP-6 (Deghenghi et al., Life Sci 1994). It acts on the ghrelin receptor, and it also binds CD36, a receptor on heart muscle and blood vessel cells (Bodart et al., Circ Res 2002). In people, small placebo-controlled studies in healthy men found a dose-related rise in GH, together with rises in prolactin and cortisol. In 12 healthy older adults given hexarelin for 16 weeks, the GH response partly weakened and recovered after stopping, and IGF-1, body composition and bone density did not change (Rahim et al., JCEM 1998). Small single-dose studies from one Italian group found a short-lived rise in the share of blood the heart pumps out per beat, including in men having bypass surgery, but not in patients with dilated cardiomyopathy. Rat studies of heart injury reported findings that did not appear to depend on GH. The human studies are small and short, and there are no large controlled trials or long-term safety data. Supplied for laboratory research use only.