Back to Study: Glycine ingestion improves subjective sleep qualit...
causal
positive effect
Taking 3 grams of glycine before bed helps people fall asleep faster, as measured by sleep monitoring equipment.
Scientific Claim
A single 3g dose of glycine before bedtime significantly reduces sleep onset latency in adults with chronic poor sleep, as measured by polysomnography (PSG) (P=0.01).
Source Excerpt
“glycine ingestion significantly shortened the latency to sleep onset (latency to the first appearance of stage 2 sleep, P=0.01)”
Evidence from Studies
Supporting Studies
Glycine ingestion improves subjective sleep quality in human volunteers, correlating with polysomnographic changes
Crossover Trial
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Evidence Assessment
Supported
The study used PSG to objectively measure sleep onset latency and found a statistically significant reduction (P=0.01) after glycine ingestion compared to placebo in a randomized crossover design. This provides causal evidence for glycine's effect on sleep onset.