New therapeutic strategy for amino acid medicine: glycine improves the quality of sleep.
Level 5 - mechanism / opinion, no new human data
Narrative review summarizing animal and human mechanistic studies.
PubMed 22293292 · doi:10.1254/jphs.11r04fm
What was done
This narrative review summarizes the authors' human and animal findings regarding bedtime oral glycine supplementation. It examines subjective sleep quality in humans alongside pharmacokinetic, thermoregulatory, and receptor-mediated neurological pathways evaluated in rat models.
What was found
The abstract reports no numerical values or statistics. It states qualitatively that bedtime glycine ingestion significantly improved subjective sleep quality in individuals with insomniac tendencies. In rats, oral glycine significantly increased plasma and cerebrospinal fluid glycine concentrations, increased cutaneous blood flow, and reduced core body temperature.
Why it matters
It outlines a biological mechanism—peripheral heat dissipation leading to reduced core body temperature—through which an amino acid supplement may facilitate sleep onset and maintenance.
Limits
The abstract provides no sample sizes, demographic characteristics, effect sizes, or trial design details for either the clinical or preclinical studies. As a non-systematic review, it is prone to narrative selection bias.
Cited by
- partial Therapeutic doses of glycine contribute significantly to promoting deep sleep.