Ipamorelin vs MK-677 (Ibutamoren)

A selective growth hormone secretagogue that stimulates pulsatile GH release from the pituitary without significantly affecting cortisol, prolactin, or appetite.

An orally active ghrelin receptor agonist that mimics growth hormone secretagogues without injections. Technically a small molecule, but included because it dominates GH-secretagogue conversations alongside CJC-1295/ipamorelin.

Ipamorelin binds the ghrelin receptor (GHSR-1a) in the pituitary, triggering growth hormone release. Unlike earlier secretagogues such as GHRP-6, ipamorelin is highly selective and does not induce hunger or stimulate cortisol.

MK-677 binds the ghrelin receptor (GHSR-1a), triggering GH and IGF-1 elevation. Unlike peptide secretagogues, it's orally bioavailable.

200–300 mcg, 1–3 times daily (research protocols)

10–25 mg oral, once daily (usually bedtime)

~2 hours

~24 hours

Subcutaneous

Oral

research-only

research-only

£21 · £4.2/mg via Peptides UK

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