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Sermorelin held FDA approval for paediatric GH deficiency from 1997 to 2008, when it was withdrawn from the US market for commercial, not safety or efficacy, reasons.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.