Glycine vs MK-677 (Ibutamoren)
Both are used for sleep better. Here's how they compare on human evidence, mechanism, safety and availability — in plain English.
| Glycine | MK-677 (Ibutamoren) | |
|---|---|---|
| Human evidence | ★★★☆☆ | ★★★☆☆ |
| Legal status | OTC Supplement | Not Approved |
| How it works | Smallest amino acid; inhibitory neurotransmitter at spinal/brainstem glycine receptors (GLRA1), lowers core body temperature (a sleep-onset trigger) via peripheral vasodilation, and supplies one-third of collagen's amino acids. Mimics some… | Orally-active non-peptide GHSR agonist; sustained GH/IGF-1 elevation and marked slow-wave-sleep enhancement (GH pulses in deep sleep). Reversed nitrogen wasting in trials. |
| In plain English | An amino acid that gently cools you down and quiets the nervous system for sleep, and is the main brick in collagen. Dirt cheap, very safe. | A pill (not an injection) that keeps growth hormone elevated via the ghrelin switch — famous for deep sleep and appetite, plus fuller muscles. Downsides are water retention and higher blood sugar. |
| Bottom line | One of the most undervalued supplements — sleep + connective tissue + longevity. | The most practical GH-optimiser without a needle. |
| Availability | Available over the counter | Not widely approved |
Which is better for sleep better?
Both carry a comparable human-evidence rating (★★★☆☆). Choose on mechanism fit, side-effects, availability and cost rather than evidence strength alone — they work through different mechanisms.
Full breakdowns: Glycine · MK-677 (Ibutamoren).
Common questions
Is Glycine or MK-677 (Ibutamoren) better for sleep better?
Both carry a comparable human-evidence rating (★★★☆☆). Choose on mechanism fit, side-effects, availability and cost rather than evidence strength alone — they work through different mechanisms.
What's the difference between Glycine and MK-677 (Ibutamoren)?
Glycine: One of the most undervalued supplements — sleep + connective tissue + longevity. — MK-677 (Ibutamoren): The most practical GH-optimiser without a needle.