Research

Hormonal

Oral administration of the ghrelin mimetic MK-677 (25 mg daily) significantly increases fat-free mass and intracellular water in healthy older adults (60-81 years) by enhancing pulsatile growth hormone secretion, without improving muscle strength or physical function.

For healthy older adults, taking 25mg of MK-677 daily for a year will increase lean body mass by about 1.1 kg compared to placebo, largely due to increased intracellular water. However, this increase in mass does not translate to stronger muscles or better physical function. Users should be aware of potential side effects including increased appetite, mild edema, and a measurable decrease in insulin sensitivity (higher fasting glucose).

GoodQualifiesHIGH confidence
Daily administration of MK-677 significantly increased growth hormone and insulin-like growth factor I levels to those of healthy young adults... Mean fat-free mass decreased in the placebo group but increased in the MK-677 group (change, -0.5 kg... vs. 1.1 kg... P < 0.001), as did body cell mass, as reflected by intracellular water... Increased fat-free mass did not result in changes in strength or function.
Ralf Nass et al. · Annals of Internal Medicine · 2008

Why this rating

Randomized, double-blind, placebo-controlled trial with a relatively long duration (12 months pivotal, 24 months exploratory) and rigorous body composition measures (4-compartment model).

Source

Effects of an Oral Ghrelin Mimetic on Body Composition and Clinical Outcomes in Healthy Older Adults

Ralf Nass et al. · Annals of Internal Medicine · 2008

DOI 10.7326/0003-4819-149-9-200811040-00003

crossover · n=65Cited 252×
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DOI resolved against Crossref · corpus check 2026-06-10

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