Oral MK-677 Increases Growth Hormone, Lean Mass, and Calorie Burning in Obese Men
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.
Quick Facts
What This Study 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.
Key Numbers
How They Did This
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.
Why This Research 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.
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.
What This Study Doesn't 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.
Questions This Raises
- ?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?
Trust & Context
- Key Stat:
- 1.8x GH increase MK-677 nearly doubled 24-hour GH secretion in obese men, restoring levels to those seen in lean young adults
- Evidence Grade:
- 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.
- Study Age:
- Published in 1998. MK-677 body composition studies have continued, with longer-duration trials in various populations.
- Original Title:
- Two-month treatment of obese subjects with the oral growth hormone (GH) secretagogue MK-677 increases GH secretion, fat-free mass, and energy expenditure.
- Published In:
- The Journal of clinical endocrinology and metabolism, 83(2), 362-9 (1998)
- Authors:
- Svensson, J(6), Lönn, L, Jansson, J O(4), Murphy, G, Wyss, D, Krupa, D, Cerchio, K, Polvino, W, Gertz, B, Boseaus, I, Sjöström, L, Bengtsson, B A
- Database ID:
- RPEP-00497
Evidence Hierarchy
Frequently Asked Questions
Can MK-677 help with weight loss?
This study showed MK-677 increased lean mass and metabolic rate in obese men, but fat loss wasn't statistically significant over 8 weeks. It may improve body composition by building muscle rather than directly burning fat.
Why is growth hormone low in obesity?
Excess body fat suppresses GH release. This creates a cycle where low GH leads to more fat storage and less muscle, which further suppresses GH. MK-677 breaks this cycle by stimulating GH release despite the obesity.
Read More on RethinkPeptides
Cite This Study
https://rethinkpeptides.com/research/RPEP-00497APA
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.
MLA
Svensson, J, et al. "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, 1998.
RethinkPeptides
RethinkPeptides Research Database. "Two-month treatment of obese subjects with the oral growth h..." RPEP-00497. Retrieved from https://rethinkpeptides.com/research/svensson-1998-twomonth-treatment-of-obese
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.