Oral MK-677 reversed the protein loss caused by calorie restriction in healthy volunteers, with effects comparable to growth hormone injections.
40% IGF-1 increaseOral MK-677 at 25 mg daily increased IGF-1 by approximately 40% and reversed nitrogen wasting in calorie-restricted healthy volunteers
What the researchers found
MK-677 at 25 mg daily reversed diet-induced nitrogen wasting in healthy volunteers, increasing IGF-1 by 40% and producing sustained anabolic effects comparable to GH injections.
Why it matters
Muscle wasting from illness, aging, or calorie restriction is a major health problem. An oral medication that prevents protein loss could help hospitalized patients, the elderly, and anyone recovering from illness maintain muscle mass.
How the study worked
Double-blind, randomized, placebo-controlled, two-period crossover study in 8 healthy volunteers (ages 24-39). Calorie restriction was used to induce negative nitrogen balance, then MK-677 or placebo was administered. Nitrogen balance, GH, IGF-1, and cortisol were measured.
What this study cannot tell us
Small sample size (8 volunteers). Short-term study in healthy young adults. Effects in actual catabolic patients (elderly, critically ill) may differ. Long-term safety not assessed.
How to read the evidence
Strong evidence from a well-designed double-blind, placebo-controlled crossover RCT, though limited by small sample size and short duration.
When this study was published
Published in 1998. MK-677 (ibutamoren) has since been studied extensively for muscle wasting, aging, and growth hormone deficiency.
The bigger picture
Most GH-boosting treatments require injections, limiting their practical use. An effective oral GH secretagogue that preserves muscle during calorie restriction could transform treatment of muscle wasting conditions, from post-surgical recovery to age-related sarcopenia.
Questions still open
- Does MK-677 prevent muscle loss in elderly patients or those with chronic illness?
- What are the long-term effects of sustained IGF-1 elevation from MK-677?
- Could MK-677 reduce hospital length of stay by preventing catabolic muscle loss?
Common questions
What is MK-677?
Can MK-677 prevent muscle loss?
Read the original research
MK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism.
The Journal of clinical endocrinology and metabolism, 83(2), 320-5
Citation
Murphy, M G; Plunkett, L M; Gertz, B J; He, W; Wittreich, J; Polvino, W M; Clemmons, D R. (1998). MK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism.. The Journal of clinical endocrinology and metabolism, 83(2), 320-5.