Tier 4 — mechanistic

Deficient synthesis of glutathione underlies oxidative stress in aging and can be corrected by dietary cysteine and glycine supplementation

Sekhar RV, Patel SG, Guthikonda AP, Reid M, Balasubramanyam A, Taffet GE, Jahoor F
The American journal of clinical nutrition 2011 94(3):847-853

Bibliography

PubMed
PMID 21795440
PubMed Central
PMC3155927
DOI
10.3945/ajcn.110.003483
Funding
Indexed support: NCRR NIH HHS; NIDDK NIH HHS. See the publication for grant and funder details.
Competing interests
The accessible abstract does not establish the authors' competing interests; absence of a statement is not evidence of no conflicts.

Study snapshot

DesignExploratory human intervention
ModelAdult humans
Sample8 older adults and 8 younger controls
InterventionCombined glycine and cysteine precursor supplementation, with cysteine supplied as NAC
Duration2 weeks
EndpointsGlutathione synthesis measured with tracers; Red-cell glutathione; Oxidative stress

What the study showed, in plain terms

This early precursor study linked low glutathione in older adults to reduced synthesis and reported improvement after combined amino-acid supplementation. It is mechanistic human evidence, not proof of slowed aging.

Key findings

  • Glutathione synthesis and concentrations increased after treatment.
  • Oxidative-stress and damage markers decreased.

What this study can and cannot tell us

Very small pre-post intervention without an older placebo group.

The study cannot identify glycine's independent contribution or establish long-term clinical benefit.

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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