MK-677 (Ibutamoren): Patient Information & Safety Notes
Also known as MK677, Ibutamoren mesylate, L-163,191
Other names: ibutamoren-mesylate, l-163191
MK-677 (ibutamoren) is an orally active, non-peptide ghrelin receptor agonist that stimulates the pituitary to release growth hormone. It has been studied in clinical trials for muscle wasting and growth hormone deficiency but has NOT received FDA approval for any indication.
In plain language
What Ibutamoren is used for
- Studied in clinical research involving growth-hormone pathways and several medical conditions; no use is FDA-approved
Taking this medicine
How it is administered
- Oral capsule
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Risks and precautions
Risks and warnings
- Water retention, weight gain
- Increased appetite
- Potential insulin resistance / elevated fasting glucose
- Joint pain
Who should not take it
- Active or past malignancy
- Diabetes or insulin resistance
- Pregnancy or breastfeeding
Common questions
Patient questions
Is MK-677 a legal supplement?
MK-677 is not FDA-approved as a drug or recognized as a safe dietary supplement. It is a research compound. Selling it as a supplement is not permitted under FDA rules. Use requires a licensed provider's oversight.
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This information is educational — not medical advice.
This page is provided for general educational purposes and summarizes publicly available data from sources such as the U.S. Food & Drug Administration. It is not a substitute for the judgment of a licensed clinician and should not be used to start, stop, or change any medication. It may be incomplete or out of date, and individual circumstances vary. Always talk with your prescriber or pharmacist about your specific medications and health conditions. If you think you may have a medical emergency, call 911.
Sources & References
Learn more about where our data comes from and how we write and review medical content.