Traditional sleeping drugs such as benzodiazepines alter the regular pattern of sleep stages, increase daytime sleepiness and reduce daytime cognitive function.
Therefore, researchers from Japan where interested in an alternative sleeping aid.
The study was a randomized, single-blinded, crossover trail.
The subjects were healthy volunteers who had been continuously experiencing unsatisfactory sleep. The subjects slept in a hospital during the study.
The subjects were randomly devided in two groups:
- one group recieved 3 grams of glycine
- the other group recieved a placebo
The supplements were taken one hour before bedtime.
The results showed that glycine ingestion shortened the latency to sleep onset and no changes in sleep stages. The subjects also reported improved sleep qualities such as satisfaction with sleep and sleep efficacy.
The researchers do not exactly know how glycine works to improve sleep quality. The mode of action of glycine is different from traditional sleeping drugs and does not result in the side effects associated with these drugs.
Thus, glycine might be a smart choice for a sleeping aid.