NAC is the supplement form of an amino acid your body uses to build glutathione, its main antioxidant. In hospitals, it saves lives after paracetamol overdose. On the shelf as a daily anti-ageing capsule, the story thins out fast.
The strongest human evidence lives in lung medicine. In a two-year randomised trial, 600 mg twice daily modestly cut flare-ups in COPD (chronic obstructive pulmonary disease, a condition that narrows and damages the airways). Meta-analyses agree the benefit exists, stays modest, and belongs to that patient group. For healthy adults there are no long-term trials testing whether NAC moves disease risk at all.
Doing it: Unless a specialist has suggested it for a lung condition, you can skip this one. Eggs, poultry, dairy and legumes feed your body the same raw material, which usually manages the rest itself.
Who it suits: People with COPD or bronchiectasis should discuss dosing with their respiratory team rather than self-treat. Everyone else gives up nothing meaningful by passing.
Sources
- Zheng JP et al., Lancet Respir Med, 2014 (PANTHEON randomised trial, COPD)
- Huang C et al., Ther Adv Respir Dis, 2023 (meta-analysis, NAC in COPD)
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