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Study breakdown

Oral MK-677 Significantly Improves Sleep Quality in Both Young and Older Adults

RPEP-004021997Copinschi, G; Leproult, R; Van Onderbergen, A; Caufriez, A; Cole, K Y; Schilling, L M; Mendel, C M; De Lepeleire, I; Bolognese, J A; Van Cauter, E
RCTModerate evidence
The takeaway

Prolonged oral MK-677 treatment significantly improved sleep quality in healthy young and older adults, increasing stage 4 (deep) sleep and REM sleep duration.

More deep sleep + more REM

MK-677 increased both stage 4 (restorative) and REM sleep in young and older adults

What the researchers found

Prolonged oral MK-677 significantly improved sleep quality by increasing stage 4 (deep sleep) and REM sleep in both young (18-30) and older (65+) adults.

Why it matters

Sleep quality declines with age alongside GH secretion. A compound that improves both simultaneously could address two major age-related health concerns.

How the study worked

Double-blind study with 8 young (18-30) and 6 older (65+) subjects receiving oral MK-677 during treatment periods. Sleep was objectively measured by polysomnography.

What this study cannot tell us

Small sample sizes (8 young, 6 older). Double-blind but specific study duration and dosing not fully detailed in abstract. Long-term effects unknown.

How to read the evidence

Moderate clinical evidence with objective polysomnography measurements. Small sample sizes but consistent effects across age groups.

When this study was published

Published in 1997, this remains one of the most cited studies for MK-677's sleep benefits.

The bigger picture

This study revealed that MK-677's benefits extend beyond GH — improving sleep architecture is independently valuable for health, recovery, and cognitive function.

Questions still open

  • Does improved sleep account for some of MK-677's body composition benefits?
  • Is MK-677's sleep improvement maintained with long-term chronic use?

Common questions

How does MK-677 improve sleep?
MK-677 increases deep (stage 4) sleep and REM sleep, likely through its effect on the GH-ghrelin axis. Growth hormone is naturally released during deep sleep, and MK-677 enhances this relationship, creating a positive feedback loop.
Is this why people take MK-677 at bedtime?
Yes. Taking MK-677 before bed amplifies the natural sleep-associated GH pulse while simultaneously improving sleep quality. This dual benefit makes bedtime dosing the standard protocol.

Read the original research

Prolonged oral treatment with MK-677, a novel growth hormone secretagogue, improves sleep quality in man.

Neuroendocrinology, 66(4), 278-86

View on PubMed ↗

Citation

Copinschi, G; Leproult, R; Van Onderbergen, A; Caufriez, A; Cole, K Y; Schilling, L M; Mendel, C M; De Lepeleire, I; Bolognese, J A; Van Cauter, E. (1997). Prolonged oral treatment with MK-677, a novel growth hormone secretagogue, improves sleep quality in man.. Neuroendocrinology, 66(4), 278-86.