In This Article
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NOW NAC N-Acetyl Cysteine 600mg
600mg per capsule — pharmaceutical-grade precursor to glutathione
8.9
NV SCORE
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NAC (N-Acetyl Cysteine) Review 2026: Glutathione, Lung Health & More
N-Acetyl Cysteine (NAC) is the precursor to glutathione — the most powerful antioxidant your body produces. Unlike taking glutathione directly (which degrades in the gut), NAC is stable, well-absorbed, and has decades of clinical use as an FDA-approved drug (mucomyst). Score: 8.9/10.
Key Benefits & Evidence
Liver protection: 8g IV NAC is the standard treatment for acetaminophen overdose in hospitals. Oral supplementation reduces ALT/AST markers in NAFLD by 20–35% in RCTs.
Lung health: Meta-analysis of 9 RCTs: 600mg/day NAC reduces COPD exacerbations by 25%. Breaks up mucus, reduces oxidative stress in lung tissue.
OCD & addiction: 3 RCTs found 2,400–3,000mg/day reduces compulsive behaviors. Glutamate regulation appears to be the mechanism.
Fertility: 1,800mg/day NAC improves sperm motility and reduces oxidative DNA fragmentation in infertile men.
Dose & Timing
600mg once or twice daily is the most studied dose. Take away from meals to reduce GI side effects (nausea at doses above 1,200mg is common). The half-life is ~6.25 hours — split dosing is more effective than a single large dose.
Important Caveat
In 2020, the FDA sent warning letters to companies selling NAC as a dietary supplement, arguing it was excluded from supplement status as an existing drug. Most sellers continue to sell it. The regulatory status remains unclear as of 2026. This does not affect the clinical evidence.
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NordVital Research Team
Evidence-Based Health Research
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