Approximate dose-response bands. Individual response varies — these are starting points, not prescriptions.
Well below target. Risk of deficiency symptoms tied to glutathione · liver.
Below the recommended daily target. Long-term adequacy not assured.
Daily target met. Standard nutritional support for glutathione · liver.
Common for specific health goals. Check the evidence for your situation before sustaining this level.
Past the point where extra intake typically helps. Evidence for further benefit is thin.
You're at 0% of your nac target. The biggest single-serving sources to top it off:
N-acetylcysteine — acetylated derivative of the conditionally essential amino acid cysteine. Used clinically as acetaminophen overdose antidote (>50 years), mucolytic, and increasingly studied for psychiatric, pulmonary, and longevity applications via its role as a glutathione precursor.
Hydrolysed to L-cysteine, which combines with glutamate and glycine via gamma-glutamylcysteine synthetase (the rate-limiting enzyme) and GSH synthase to produce reduced glutathione. GSH then donates electrons to oxidised substrates and to detoxify xenobiotics. The acetyl group makes NAC more stable and better-absorbed than free L-cysteine.
Not an essential nutrient — cysteine is the relevant precursor and is met by adequate dietary methionine/cysteine intake. Glutathione status may be marginal in chronic illness and aging.
Well-tolerated up to ~6 g/day orally; higher IV doses used in overdose. Sulfur metabolites can produce odour and mild GI upset.
N-acetyl-cysteine (NAC) at 600–1,200 mg/day in divided doses. Take on an empty stomach for absorption. Sulfur smell is normal. Don't combine with nitroglycerin without medical supervision. FDA contested NAC's dietary-supplement status briefly (2020-2022) but enforcement discretion has returned to allowing OTC sale.
Oral bioavailability of intact NAC is low (~10%) due to first-pass metabolism, but conversion to cysteine and incorporation into GSH is reliable. Empty stomach improves uptake. Plasma cysteine peaks at 1–2 h.
Glutathione status declines with age. GlyNAC (glycine + NAC, 1.3 g + 1 g of each per day in trials) restored GSH levels and improved mitochondrial function, insulin sensitivity, and inflammatory markers in older adults. Mechanism is well-grounded; outcome trials are early but promising.
N-acetyl-cysteine; glutathione precursor, antioxidant, mucolytic. Common dose 600–1200 mg.
The mechanisms and systems this nutrient feeds. Click any to drill into what runs on it.
★ = load-bearing / primary cofactor. Track these in My Journey.