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Home>>Peptides>>MK-677 (Ibutamoren)
Clinical-stage WADA prohibitedGH / growth factors

MK-677 (Ibutamoren)

An orally active, non-peptide ghrelin-receptor agonist that raises GH and IGF-1 levels. Human trials were conducted, but development was discontinued and it was never approved.

CompoundMK-677 (Ibutamoren)
CategoryOral GH secretagogue
ClassGrowth Hormone and Growth Factors
Evidence tierClinical-stage
WADA statusProhibited in sport (or falls under a prohibited class) — see the WADA reference table
Sold on this siteNo — this is a reference database

Overview

MK-677 (Ibutamoren) — a oral gh secretagogue — sits in the "Clinical-stage" tier of this catalog. This compound has completed or is undergoing formal human trials. Human safety and efficacy are being characterized, but no universal approval exists and results may still fail or be withdrawn.

An orally active, non-peptide ghrelin-receptor agonist that raises GH and IGF-1 levels. Human trials were conducted, but development was discontinued and it was never approved.

Mechanism of Action

Ibutamoren is a small-molecule agonist of the ghrelin receptor, producing sustained GH stimulation and appetite increase; oral bioavailability was its distinguishing feature.

Research and Evidence

Multiple human trials demonstrated increased GH and IGF-1, including studies in elderly and obesity populations; some raised glucose concerns, and development stopped before any approval.

Evidence in context: the Growth Hormone and Growth Factors class page collects the shared evidence themes and study-reading guidance for this category.

Safety and Side Effects

Reported effects include increased appetite, transient water retention, joint pain, and — importantly — worsening of insulin sensitivity and glucose tolerance. It is prohibited in sport.

Educational notice: this entry describes published research and, where they exist, regulator labels. It is not medical advice and not a recommendation for use. Research-grade compounds have no verified human-safety data.

Frequently Asked Questions

What is the evidence tier of MK-677 (Ibutamoren)?

MK-677 (Ibutamoren) is graded "Clinical-stage" on this site. This compound has completed or is undergoing formal human trials. Human safety and efficacy are being characterized, but no universal approval exists and results may still fail or be withdrawn.

Is MK-677 (Ibutamoren) an approved medicine?

No. Clinical-stage means the compound has not reached universal regulatory approval; the tier description above explains exactly what level of evidence exists.

Where can I read the primary studies for MK-677 (Ibutamoren)?

The references section at the end of this entry links the key primary sources — regulator labels, trial registrations, and peer-reviewed papers. Our "How to Read a Peptide Study" guide explains how to evaluate them.

References

  1. ClinicalTrials.gov — registered ibutamoren / MK-677 studies. [source]
  2. WADA Prohibited List. [source]
EM
Dr. Elena Marsh, PhDMolecular Pharmacology · Lead Editor

Written and maintained by the editorial team. Medically reviewed by Dr. James Okafor, MD (Internal Medicine).

Evidence tier: Clinical-stage · Last reviewed: 2026-09-05 · Sources cited below.

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