Ipamorelin vs Hexarelin

Ipamorelin

A selective ghrelin-receptor agonist that triggers a GH pulse without raising cortisol or prolactin — the property that made it the default GHRP and pushed the older, dirtier GHRPs to the margins.

Best for

Best for long cycles (12+ weeks). No cortisol or prolactin lift; the receptor stays sensitive longer.

Hexarelin

The most potent GHRP per microgram — and the one that desensitises fastest. A short-cycle tool, not a long-term protocol, with a cortisol lift that Ipamorelin avoids.

Best for

Best for short, intense recovery sprints (max 6 weeks). Bigger GH pulse, but receptor desensitises faster and cortisol creeps up.

Ipamorelin

Original pharmacology work by Raun and colleagues (1998) established the GH-selectivity profile — the absence of cortisol and prolactin lift is what differentiates this peptide from the older GHRPs and the data on that point is reproducible. Long-term outcome trials in healthy adults are not the literature's strong suit. The pulse pharmacology is tight; the chronic body-recomp evidence is anecdotal-plus-mechanism rather than RCT-based.

Hexarelin

Multiple short clinical pharmacology studies from the 1990s — including the canonical Imbimbo and colleagues work — characterise the GH pulse, the cortisol/prolactin lift, and the desensitisation kinetics. The cardioprotective signal through CD36 is mostly animal data. No long-term outcome trials in healthy adults. Use it for the short-cycle pharmacology it was studied for; the chronic-use evidence base does not exist.