COMPOUND

Compounds / GH secretagogues

MK-677

Ibutamoren Mesylate

GH secretagogues Oral Not FDA approved

Oral GH secretagogue. Not a peptide: a small molecule ghrelin mimetic. Convenient daily pill but causes strong appetite increase and water retention.

At a glance

Half-life
~24 h ~24 hours. Allows once-daily oral dosing.
Routes
Oral
Evidence base
1 study 1 human

Mechanism

Oral GHS-R1a agonist. Mimics ghrelin, stimulates pituitary GH release, suppresses somatostatin. Increases IGF-1 chronically. 24-hour half-life allows once-daily dosing. 2-year RCT: increased GH/IGF-1 and fat-free mass (+1.1 kg vs -0.5 kg placebo) but elevated fasting glucose.

Dosing

Any amounts shown here are reported from published studies only. 1 of 1 catalogued study involved human subjects. COMPOUND does not publish its own dosing guidance.

Published evidence

  1. Human RCT 2008

    Effects of an oral ghrelin mimetic on body composition in healthy older adults: a randomized trial

    Nass R, Pezzoli SS, Oliveri MC, et al. Ann Intern Med

    2-year RCT: MK-677 increased GH/IGF-1, fat-free mass +1.1kg vs -0.5kg placebo, but increased fasting glucose.

    PMID 18981485

Reported side effects

Increased appetite
Very common Moderate · Strong; mimics ghrelin (the hunger hormone). #1 complaint.
Water retention/edema
Very common Moderate · GH-mediated. Especially lower extremity.
Elevated fasting glucose
Common Moderate · ~5 mg/dL average increase. Reduced insulin sensitivity with chronic use.
Lethargy
Occasional Mild
Numbness/tingling
Occasional Mild

Interactions

  • Ipamorelin Redundant

    MK-677 and injectable ghrelin mimetics (ipamorelin, GHRP-2) hit the same receptor. Combining is redundant.

Storage

Store capsules at room temperature. Liquid form: refrigerate after opening.