Two months of daily oral MK-677 restored GH secretion to normal levels in obese men while increasing fat-free mass and energy expenditure without significant side effects.
1.8x GH increaseMK-677 nearly doubled 24-hour GH secretion in obese men, restoring levels to those seen in lean young adults
What the researchers found
MK-677 (25 mg/day for 8 weeks) increased 24-hour GH secretion rate by 1.8-fold, normalized pulsatile GH profiles, increased fat-free mass by ~3 kg, and raised basal metabolic rate in obese males.
Why it matters
Obesity creates a vicious cycle: excess fat suppresses GH, which promotes more fat storage and muscle loss. An oral medication that breaks this cycle by restoring GH secretion could fundamentally change how obesity-related metabolic dysfunction is treated.
How the study worked
Randomized, double-blind, placebo-controlled parallel study. 24 obese males (BMI >30, ages 19-49) received MK-677 25 mg/day or placebo for 8 weeks. GH profiles (24-h sampling), body composition (DEXA), and energy expenditure measured.
What this study cannot tell us
Small sample (24 men). Only 8 weeks duration. Body fat changes were not statistically significant despite favorable trends. All participants were male; effects in women unknown.
How to read the evidence
Strong evidence from a well-designed double-blind RCT with objective measurements (24-hour GH sampling, DEXA body composition), though limited by small sample and short duration.
When this study was published
Published in 1998. MK-677 body composition studies have continued, with longer-duration trials in various populations.
The bigger picture
The metabolic consequences of obesity go beyond calories — hormonal disruption including GH deficiency drives unfavorable body composition. Restoring GH with an oral secretagogue represents a novel approach to obesity-related metabolic dysfunction.
Questions still open
- Would longer treatment lead to significant fat loss as well?
- Does the increased energy expenditure persist with continued use?
- Would MK-677 benefit elderly obese individuals where GH deficiency is more severe?
Common questions
Can MK-677 help with weight loss?
Why is growth hormone low in obesity?
Read the original research
Two-month treatment of obese subjects with the oral growth hormone (GH) secretagogue MK-677 increases GH secretion, fat-free mass, and energy expenditure.
The Journal of clinical endocrinology and metabolism, 83(2), 362-9
Citation
Svensson, J; Lönn, L; Jansson, J O; Murphy, G; Wyss, D; Krupa, D; Cerchio, K; Polvino, W; Gertz, B; Boseaus, I; Sjöström, L; Bengtsson, B A. (1998). Two-month treatment of obese subjects with the oral growth hormone (GH) secretagogue MK-677 increases GH secretion, fat-free mass, and energy expenditure.. The Journal of clinical endocrinology and metabolism, 83(2), 362-9.