Tier 2 — strong

The cognitive effects of modulating the glycine site of the NMDA receptor with high-dose glycine in healthy controls

Palmer C, Ellis KA, O'Neill BV, Croft RJ, Leung S, Oliver C, Wesnes KA, Nathan PJ
Human psychopharmacology 2008 23(2):151-159

Bibliography

PubMed
PMID 17972276
DOI
10.1002/hup.904
Funding
Funding was not specified in the indexed abstract; the full funding disclosure has not been verified.
Competing interests
The accessible abstract does not establish the authors' competing interests; absence of a statement is not evidence of no conflicts.

Study snapshot

DesignRandomized controlled human intervention
ModelAdult humans
Sample13 healthy young participants in the reported crossover study
InterventionAcute oral glycine 0.8 g/kg versus placebo; 5-day washout
DurationSingle-dose testing per condition
EndpointsWorking memory; Declarative memory; Attention; Perceptual processing

What the study showed, in plain terms

A controlled high-dose experiment found no cognitive advantage from acute glycine in healthy young adults. It is an important counterpoint to positive findings from selected clinical populations or other formulations.

Key findings

  • No significant effect was found on the tested memory, attention or perceptual-processing measures.
  • The dose was far higher than the 3 g used in the small bedtime studies.

What this study can and cannot tell us

Small, acute study; it cannot rule out effects in every population or regimen.

Different dose and participants mean this result should not be used to negate or validate the bedtime sleep findings.

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Editorial review

Reviewed by the Biohack Blueprint research team

Last verified

Dr. Khaled Mahmoud, MBBChCritical Care Medicine, Longevity Science & Editorial Direction