Ipamorelin vs Sermorelin

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 when you want a selective GH pulse with no cortisol, prolactin, or hunger.

Sermorelin

The oldest GHRH analogue still in widespread use — the first 29 amino acids of natural GHRH, unmodified. Pulses the pituitary in line with the body's natural sleep-onset GH window.

Best for

Best when you want to restore the natural GHRH signal in a sleep-aligned, physiologic way with an FDA history.

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.

Sermorelin

Sermorelin held FDA approval for paediatric GH deficiency from 1997 to 2008, when it was withdrawn from the US market for commercial — not safety or efficacy — reasons. The paediatric trial base is real and was good enough to clear regulatory review. Adult body-recomposition and anti-aging use is off-label and supported by smaller open-label work and the on-label pharmacology rather than a dedicated RCT base in healthy adults. The chronic safety record is reassuring across 25+ years of clinical and grey-market use.