Glycine and N-acetylcysteine supplementation, with or without exercise, in brain health and functional aging: implications for sarcopenia and frailty in older adults.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing preclinical and clinical literature with no systematic search methodology.
PubMed 42232577 · doi:10.3389/fnut.2026.1775264
What was done
Narrative review evaluating preclinical and clinical literature on glycine, N-acetylcysteine (NAC), and combined GlyNAC supplementation, with or without exercise, for targeting oxidative stress, mitochondrial dysfunction, sarcopenia, and cognitive decline in aging.
What was found
The abstract provides no quantitative data. It reports context-dependent benefits of NAC on glutathione availability, fatigue resistance, and exercise performance in individuals with low baseline glutathione, with inconsistent results in healthy groups. Glycine shows mixed effects on anaerobic performance and lactate clearance. Combined GlyNAC supplementation demonstrates proof-of-concept improvements in oxidative stress, mitochondrial function, insulin resistance, inflammation, muscle strength, cognition, and animal lifespan.
Why it matters
Synthesizes current evidence positioning GlyNAC, particularly alongside exercise, as a candidate nutritional intervention to address key hallmarks of aging and functional decline.
Limits
As a narrative review, it lacks systematic search criteria, risk-of-bias assessment, and meta-analytic pooling. The abstract provides no quantitative effect sizes, dosing specifics, or participant counts, and findings rely heavily on mixed, preliminary, and animal data.
Cited by
- supports Supplementation with N-acetylcysteine (NAC) enhances glutathione production.