New therapeutic strategy for amino acid medicine: glycine improves the quality of sleep
Bannai M, Kawai N
Published in Journal of Pharmacological Sciences
Methodology
Narrative review of the authors' human trials and rat studies on pre-bedtime oral glycine, sleep quality and thermoregulation
Key Findings
Glycine ingestion before bedtime improved subjective sleep quality in people with insomniac tendencies; oral glycine raised plasma and CSF glycine and lowered core body temperature via increased cutaneous blood flow, a plausible mechanism for faster sleep onset and deeper sleep.
Conclusions
Glycine appears to improve sleep quality partly by lowering core body temperature at sleep onset.
Limitations
Narrative review by industry-affiliated authors summarising their own small human trials; no pooled analysis and limited polysomnographic data.
Supplements Studied
Oral administration of glycine to rats was found to induce a significant increase in the plasma and cerebrospinal fluid glycine concentrations and a significant decrease in the core body temperature.
Outcomes Measured
Glycine ingestion before bedtime significantly ameliorated subjective sleep quality in individuals with insomniac tendencies.
Study Details
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Disclosures
Funding
Ajinomoto Co., Inc. (author affiliation)
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