Evidence-based·Last reviewed May 30, 2026·How we grade evidence

MK-677 (Ibutamoren)

Peptide

Useful mainly for not established — investigational.

Research compound — not an approved drug or dietary supplement

This compound is sold for research and is not FDA-approved for human use or as a dietary supplement. Human evidence is limited; purity and dosing of consumer products are unverified. The data below is an evidence review for education only — talk to a clinician before considering it.

Quick decision guide

May help most

Not established — investigational

Watch out for

Unapproved GH secretagogue; raises IGF-1 with risks to glucose tolerance and unknown long-term safety, often sold illegally as a 'supplement'

What is it

MK-677 (ibutamoren) is an orally active, non-peptide growth-hormone secretagogue that mimics ghrelin to stimulate the pituitary to release growth hormone and raise IGF-1. It was investigated pharmaceutically (including for conditions such as frailty and growth hormone deficiency) but was never FDA-approved, and development for marketed indications was discontinued. It is widely sold as a 'research chemical' and misrepresented as a dietary supplement (which it is not — the FDA has warned that ibutamoren is not a lawful dietary ingredient). Human data exist from clinical trials, but long-term safety is not established and it is prohibited in sport.

Is it worth it for you?

Use this as a quick fit check, not a diagnosis.

Probably skip if…

You expect an approved drug or a legal dietary supplement — it is neither (FDA has flagged it as not a lawful dietary ingredient)
You would source it from 'research chemical' vendors with no purity, dosing, or quality oversight
You are not prepared for known effects like raised blood glucose/insulin resistance and water retention
You are not prepared for unknown long-term safety of chronically elevated GH/IGF-1
You compete in sport — ibutamoren is prohibited under WADA rules

Safety

Know the common side effects, key cautions, and who should avoid it.

Common side effects

Reported in trials: increased appetite, water retention/edema, transient fatigue or lethargy, joint/muscle aching, and increases in fasting blood glucose

Serious risks

  • Impaired glucose tolerance / insulin resistance and raised blood sugar

  • Unregulated purity and dosing of research-grade product (and mislabeled 'supplements')

  • Unknown long-term effects of sustained GH/IGF-1 elevation, including theoretical risk of promoting existing tumors; one heart-failure trial in elderly patients was halted over a safety signal

  • No clinical monitoring of glucose, IGF-1, or cardiac status when self-administered

Who should avoid it

  • Anyone using it without direct medical supervision
  • Pregnancy and breastfeeding
  • People with diabetes, prediabetes, or impaired glucose tolerance
  • People with heart failure or significant cardiovascular disease
  • People with cancer or a history of cancer
  • Competitive athletes subject to anti-doping rules

Pregnancy & breastfeeding

Avoid — no safety data.

Choosing a product

What to look for on the label — and what to be skeptical of.

Be skeptical of…

'Proven' muscle-building, fat-loss, or anti-aging claims
Marketing it as a legal dietary supplement or 'natural' GH booster
Vendors selling 'for research use only' product for human consumption

Track MK-677 (Ibutamoren) with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

Coming to App Store
Evidence-based·Last reviewed May 30, 2026·Evidence current as of May 30, 2026·How we grade evidence

Disclaimer: This compound is not approved by the FDA for human use and is not a dietary supplement. This page is an educational review of available research — much of it preclinical or early-stage — not a recommendation to use it. Consumer product quality is unregulated. Consult a qualified clinician.