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Growth hormone

MK-677 (ibutamoren): Effects, Evidence and Risks

Research use only: MK-677 (Ibutamoren) is not approved as a medicine. It is offered as a research substance labelled “for research purposes only – not for use in humans or animals”. This page summarises the state of research and is not a recommendation to use it.

Also known as Ibutamoren, MK-677, MK-0677, “Nutrobal”.

StatusNot approved
EvidenceLarge studies
Drug classNon-peptide ghrelin receptor agonist (oral GH secretagogue) · tablets/capsules/solution
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What is MK-677 (ibutamoren)?

Ibutamoren is not a peptide but an orally active small molecule that activates the ghrelin receptor. It thereby raises growth hormone and IGF-1 and markedly increases appetite.

How well studied is MK-677 (ibutamoren)?

There are several randomised trials, including in older adults, after hip fracture and in Alzheimer's disease (no clinical benefit there). GH/IGF-1 and lean mass rose in some trials, but a clear benefit for strength or function was not shown; one trial was stopped early because of a heart failure signal.

What side effects and risks does MK-677 (ibutamoren) have?

Strong hunger, fluid retention and joint/muscle pain are common. Ibutamoren raises fasting blood glucose and worsens insulin sensitivity – critical with prediabetes or during diabetes/GLP-1 therapy. The FDA warns of a possible risk of heart failure; grey-market products (often sold as “SARMs”) are frequently mislabelled.

Is MK-677 (ibutamoren) approved in Germany?

In short: no. Not approved as a medicine anywhere; not legally marketable as a supplement in the EU. Prohibited in sport (WADA S2, GH secretagogues); may fall under the German AntiDopG. The FDA has issued warning letters to sellers – high quality and counterfeit risk.

Sources

Note: We deliberately do not list any doses here. For approved medicines, your doctor sets the dose; for unapproved substances there is no reliable information.