Taking 3 grams of glycine before bed makes people who have trouble sleeping feel more satisfied with their sleep.
Scientific Claim
A single 3g dose of glycine taken before bedtime significantly improves subjective sleep satisfaction in adults with chronic poor sleep, as measured by the St. Mary's Hospital Sleep Questionnaire (P=0.046).
Source Excerpt
“Significant beneficial effects of glycine were revealed in Question 11 'How satisfied were you with last night's sleep?' (P=0.046, Fig. 1)”
Evidence from Studies
Supporting Studies
Glycine ingestion improves subjective sleep quality in human volunteers, correlating with polysomnographic changes
This was a randomized single-blinded crossover trial with 11 participants showing statistically significant improvement in sleep satisfaction (P=0.046) after glycine ingestion compared to placebo. The study design allows for causal inference despite small sample size.