NAC (N-Acetyl Cysteine)
Antioxidants & respiratoryFunction & benefits
A derivative of the sulphur amino acid L-cysteine and the limiting factor for making the cellular antioxidant glutathione in the liver and lungs; its free sulphur groups help break down thick mucus, supporting comfortable airways.
Dosage & how to use
| Recommended dose | 600–1200 mg daily |
| Best time to take | On an empty stomach with a full glass of water, or with a light snack to avoid heartburn |
| Frequency | Split into two doses |
Best forms to choose
Pure free-form NAC capsules; a mild sulphur smell is normal and shows the active thiol groups are present.
Important warnings
May cause nausea and mild heartburn; take it with two glasses of water
Not for people with a cysteine allergy or rare cystine kidney stones
It is classed as a medicine in some European countries; use it according to local rules
Drug interactions
Angina medication warning: it interacts with nitroglycerin and other nitrates and can cause a sharp drop in blood pressure and a severe headache. Take it two hours apart from oral antibiotics and activated charcoal.
Related supplements
- Daily MultivitaminsGeneral health & immunity
- Omega-3 Fish OilGeneral & heart health
- Vitamin D3 (Cholecalciferol)General health & bones
- Magnesium (Glycinate/Citrate)General health & nerves
Scientific references
- Šalamon Š et al. Antioxidants (Basel) 2019 — PMID: 31035402
- NIH National Library of Medicine (MedlinePlus): N-acetyl cysteine
Content last updated: 17 October 2026 · Based on published sources and research (EFSA / NIH / PubMed)
⚖️ Medical disclaimer: The information and data provided here are for health education and nutritional guidance only. They are not a medical diagnosis and never replace a direct consultation with your doctor or pharmacist. Always consult your doctor before starting any supplement, especially during pregnancy or breastfeeding or when taking long-term medication.