Hexarelin

Hexarelin is a six-residue growth hormone secretagogue derived from the GHRP family. It is more potent than ipamorelin at GHS-R1a but markedly less selective, producing measurable cortisol and prolactin responses in published work. What makes it interesting rather than simply dirty is a second, independent binding site: hexarelin binds CD36, a scavenger receptor expressed on cardiac tissue and macrophages, and a substantial share of the cardiovascular literature on this compound concerns CD36 rather than the growth hormone axis at all.

That dual pharmacology means hexarelin is the wrong tool if you want clean growth hormone signalling and the right tool if you are specifically interested in CD36. Choosing between it and ipamorelin on potency alone is the common mistake.