MK-677

What people use it for

• Raising growth hormone and IGF-1 (popular use)
• Muscle, sleep and recovery (popular claims)
• Age-related muscle loss (past clinical research)

What MK-677 does in the body

A small molecule that mimics ghrelin, the hunger hormone, at its receptor in the brain and pituitary gland. This triggers growth hormone release and raises IGF-1 levels for as long as it is taken.

Strength of evidence

Limited: small clinical trials showed raised GH and IGF-1 and some changes in body composition, but no clear functional benefit; development as a medicine did not go ahead.

Look up the evidence

• Reviews on PubMed: Summaries of the published research
• Clinical trials on PubMed: Published studies in people
• ClinicalTrials.gov: Registered trials, past and ongoing

Live searches of official databases. New to the terms? See the glossary.

Reported side effects & risks

• Increased hunger
• Water retention, swelling and joint pain
• Higher blood sugar and reduced insulin sensitivity
• A heart failure signal was reported in one trial in older adults

Who should avoid it or take extra care

• Diabetes or prediabetes
• Heart failure
• Pregnant or breastfeeding
• Current or past cancer (it may promote cell growth; theoretical)
• Competitive athletes (prohibited by WADA)

Not a complete list. Check with a doctor or pharmacist about your own health and medicines.

Regulatory status

Not approved anywhere. Sold online as a 'research chemical'. Prohibited in sport by WADA.

How it's taken

Route: By mouth (capsule or liquid), once daily

How long it lasts (half-life): About 24 hours of effect