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N-acetylcysteine

Overview

N-acetylcysteine is a supplemental form used as a cysteine precursor. It is not cysteine, and it is not the cystine measured in food tables. The cysteine page holds the amino acid and the food-composition relationship.

In older adults, two weeks of N-acetylcysteine together with glycine raised red-cell glutathione synthesis that had been lower than in younger adults [1]. The precursor was given with glycine, so the rise does not isolate N-acetylcysteine. The trial does not show an effect of N-acetylcysteine alone, of ordinary foods, or of supplementation outside that older-adult group, and it did not measure a neuronal or clinical outcome [1].

Dietary Origin

Exposure here is a direct supplement: N-acetylcysteine plus glycine, for two weeks, in older adults [1]. Ordinary foods are not that exposure. Cystine in protein is recorded on the cysteine page and is a different chemical measurement from this precursor.

Research Spotlights & Evidence Checks

🔎 Evidence Check · combination-formulation

Does the glutathione rise belong to N-acetylcysteine alone?

No. Older adults received N-acetylcysteine together with glycine. The increase in red-cell glutathione synthesis is that combination [1].

Read the evidence

Older adults had lower red-cell glutathione synthesis than younger adults. Two weeks of the cysteine precursor plus glycine raised synthesis [1]. Because both were given, the result cannot be assigned to N-acetylcysteine alone, to glycine alone, or to a food that contains cystine [1].

Recipes

no recipes found (no foods contain this substance)

Foods

no foods found

Biological Regulatory Systems

Biological Regulatory System	Evidence-qualified relationship	Evidence
Methylation & One-Carbon Metabolism (BRS2)	N-acetylcysteine is the supplemental cysteine precursor used with glycine in the older-adult glutathione-synthesis trial mapped to glutathione synthesis. The rise does not isolate N-acetylcysteine and is not an ordinary-food result.	[1]

References

[1] Sekhar et al. (2011). Deficient synthesis of glutathione underlies oxidative stress in aging and can be corrected by dietary cysteine and glycine supplementation. Older adults had lower red-cell glutathione synthesis than younger adults. Two weeks of N-acetylcysteine together with glycine raised that synthesis. The trial does not isolate N-acetylcysteine, does not measure the brain, and is not an ordinary-food result.