MK-677 raised IGF-1 levels in elderly hip fracture patients but failed to improve most functional outcomes, and the trial was stopped early due to congestive heart failure cases.
Trial stopped earlyTerminated due to congestive heart failure signal in MK-677-treated elderly hip fracture patients despite significant IGF-1 increases
What the researchers found
In 123 elderly hip fracture patients randomized to MK-677 (25 mg/day) or placebo for 24 weeks, MK-677 significantly increased IGF-1 levels by 51.4 ng/ml compared to placebo (p < 0.001). Gait speed showed a modest but significant improvement (0.7-score difference, p = 0.011). However, stair climbing power did not significantly improve (12.5 W increase, p = 0.292), and several other functional measures showed no benefit.
The MK-0677 group had fewer falls than placebo, though this did not reach statistical significance (p = 0.096). Critically, the trial was terminated early due to a safety signal of congestive heart failure in a limited number of treated patients, leading to the conclusion that MK-677 has an unfavorable risk-benefit profile in elderly hip fracture patients.
Why it matters
MK-677 (ibutamoren) is one of the most popular growth hormone secretagogues in the peptide community. This trial provides critical safety data showing that raising IGF-1 doesn't automatically translate to functional improvement, and that MK-677 can cause serious cardiac side effects in vulnerable elderly patients. It's a cautionary study for anyone considering MK-677, particularly older adults.
How the study worked
This was a multicenter, randomized, double-blind, placebo-controlled Phase IIb study. 123 elderly hip fracture patients were randomized to receive either 25 mg/day of oral MK-677 (n=62) or placebo (n=61). Primary outcomes were objective functional performance measures (stair climbing power, gait speed, and others) and blood IGF-1 levels, assessed over 24 weeks.
What this study cannot tell us
The trial was terminated early due to safety concerns, which means the study was underpowered to detect all potential functional benefits. The sample size of 123 is modest. The study focused on a specific elderly population recovering from hip fracture, and results may not apply to younger or healthier MK-677 users. The specific number of heart failure cases and their clinical details are not fully described in the abstract.
How to read the evidence
This is a multicenter, randomized, double-blind, placebo-controlled Phase IIb trial — one of the strongest study designs. However, early termination reduced statistical power, and the safety signal adds important cautionary context to the findings.
When this study was published
Published in 2011, this remains one of the most important safety studies for MK-677 in elderly populations. The findings have not been superseded and continue to inform risk-benefit discussions about growth hormone secretagogues in vulnerable patients.
The bigger picture
This trial is part of a larger story about whether raising growth hormone and IGF-1 levels can improve recovery and function in aging populations. While the biological rationale seemed sound — hip fracture patients lose muscle and function rapidly — the results highlight that pharmacologically boosting the GH/IGF-1 axis doesn't guarantee clinical benefit and can introduce serious risks. This has implications for the broader use of GH secretagogues in elderly populations.
Questions still open
- Why did MK-677 raise IGF-1 significantly but fail to improve most functional outcomes — is there a disconnect between IGF-1 levels and muscle recovery in elderly patients?
- What was the mechanism behind the congestive heart failure cases — was it fluid retention, direct cardiac effects, or pre-existing vulnerability?
- Would lower doses of MK-677 retain any benefit while avoiding the cardiac safety signal?
Common questions
What is MK-677 and why was it tested for hip fracture recovery?
Does this mean MK-677 is dangerous for everyone?
Read the original research
MK-0677 (ibutamoren mesylate) for the treatment of patients recovering from hip fracture: a multicenter, randomized, placebo-controlled phase IIb study.
Archives of gerontology and geriatrics, 53(2), 183-9
Citation
Adunsky, Abraham; Chandler, Julie; Heyden, Norman; Lutkiewicz, Jeannine; Scott, Boyd B; Berd, Yuliya; Liu, Nancy; Papanicolaou, Dimitris A. (2011). MK-0677 (ibutamoren mesylate) for the treatment of patients recovering from hip fracture: a multicenter, randomized, placebo-controlled phase IIb study.. Archives of gerontology and geriatrics, 53(2), 183-9. https://doi.org/10.1016/j.archger.2010.10.004