Tier 2 — strong

High-dose glycine inhibits the loudness dependence of the auditory evoked potential (LDAEP) in healthy humans

O'Neill BV, Croft RJ, Leung S, Oliver C, Phan KL, Nathan PJ
Psychopharmacology 2007 195(1):85-93

Bibliography

PubMed
PMID 17646968
DOI
10.1007/s00213-007-0870-4
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
Sample14 healthy participants
InterventionSingle oral glycine 0.8 g/kg versus placebo
DurationAcute repeated-measures testing
EndpointsLoudness dependence of auditory evoked potentials

What the study showed, in plain terms

Glycine changed the relationship between sound intensity and an auditory evoked potential. The study shows that this marker is influenced by more than serotonin signaling; it does not demonstrate better attention or mood.

Key findings

  • The N1/P2 response showed a weaker loudness-dependent slope with glycine.
  • The authors discussed NMDA and inhibitory signaling as possible explanations.

What this study can and cannot tell us

The exact neural mechanism was not directly established.

Small high-dose surrogate-endpoint experiment; do not count related publications automatically as independent replications.

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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