Seven days of bedtime oral MK-677 at 25 mg significantly increased 24-hour GH profiles and IGF-1 levels in healthy young men without disrupting cortisol rhythms.
25 mg effective, 5 mg notThe 25 mg bedtime dose significantly increased GH and IGF-1, while 5 mg showed lesser effects
What the researchers found
Bedtime MK-677 at 25 mg for 7 days significantly increased 24-hour GH profiles and IGF-1 in young men without altering adrenocortical function.
Why it matters
This study established a practical dosing protocol (25 mg at bedtime) for MK-677 and confirmed it works in young men without disrupting the cortisol axis — a key safety consideration.
How the study worked
Randomized, double-blind, three-period crossover study. 9 healthy young men received placebo, 5 mg, or 25 mg MK-677 orally at bedtime for 7 consecutive days per period. 24-hour GH profiles, IGF-1, and cortisol were measured.
What this study cannot tell us
Very small sample (9 men). Only 7-day treatment period. No women included. Limited to hormonal endpoints without functional outcome measures.
How to read the evidence
Strong study design (randomized, double-blind, crossover) but very small sample size (9). Provides robust individual-level data but limited generalizability.
When this study was published
Published in 1996, this is a key early dosing study for MK-677. The 25 mg bedtime protocol it established remains the standard reference dose.
The bigger picture
This study helped establish the standard MK-677 dosing protocol (25 mg at bedtime) that is widely referenced in subsequent research and clinical practice.
Questions still open
- Does the GH-boosting effect of MK-677 persist with longer-term use, or does tolerance develop?
- Would women show similar responses to MK-677 at these doses?
Common questions
Why is MK-677 taken at bedtime?
Did MK-677 affect cortisol levels?
Read the original research
Effects of a 7-day treatment with a novel, orally active, growth hormone (GH) secretagogue, MK-677, on 24-hour GH profiles, insulin-like growth factor I, and adrenocortical function in normal young men.
The Journal of clinical endocrinology and metabolism, 81(8), 2776-82
Citation
Copinschi, G; Van Onderbergen, A; L'Hermite-Balériaux, M; Mendel, C M; Caufriez, A; Leproult, R; Bolognese, J A; De Smet, M; Thorner, M O; Van Cauter, E. (1996). Effects of a 7-day treatment with a novel, orally active, growth hormone (GH) secretagogue, MK-677, on 24-hour GH profiles, insulin-like growth factor I, and adrenocortical function in normal young men.. The Journal of clinical endocrinology and metabolism, 81(8), 2776-82.