The Effects of Glycine on Subjective Daytime Performance in Partially Sleep-Restricted Healthy Volunteers

Bannai M, et al.

Published in Frontiers in Neurology

Methodology

Randomised double-blind placebo-controlled crossover study giving 3 g glycine or placebo before sleep during three nights of partial sleep restriction, with subjective fatigue/sleepiness scales and psychomotor vigilance testing.

Key Findings

In 10 healthy volunteers restricted to 25% less sleep for three nights, 3 g of glycine before bed reduced subjective daytime fatigue and sleepiness and improved performance on a psychomotor vigilance task compared with placebo.

Conclusions

Glycine before bed lessened the daytime consequences of mild sleep restriction in a very small crossover study, an encouraging but preliminary signal.

Limitations

Only 10 healthy young participants, one-week crossover with mild sleep restriction rather than clinical insomnia, largely self-reported outcomes, and industry funding by a glycine manufacturer.