Amino acids
N-acetylcysteine (NAC)
Also called: NAC, acetylcysteine
A form of the amino acid cysteine; the body uses it to make glutathione. Also a prescription medicine.
- Why people take it
- Lung mucus, liver protection, mental health, PCOS.
- What the evidence says
- A proven antidote for paracetamol overdose (given in hospital). Some evidence for mucus and for certain psychiatric conditions.
- How it is usually taken
- Usually 600 to 1,800 mg a day in divided doses.
- Be careful
- Nausea and a sulphur smell. Can interact with nitroglycerin. Asthma patients can get wheezing.
- Medicines it can interact with
- Adds to the effects of nitroglycerin (low blood pressure, headache). Can be taken with antibiotics but 2 hours apart.
Other amino acids
Common questions
What is N-acetylcysteine?
A form of the amino acid cysteine; the body uses it to make glutathione. Also a prescription medicine.
Why do people take N-acetylcysteine?
Lung mucus, liver protection, mental health, PCOS.
Does N-acetylcysteine work?
A proven antidote for paracetamol overdose (given in hospital). Some evidence for mucus and for certain psychiatric conditions.
How much N-acetylcysteine do people take?
Usually 600 to 1,800 mg a day in divided doses.
Is N-acetylcysteine safe?
Nausea and a sulphur smell. Can interact with nitroglycerin. Asthma patients can get wheezing.
Does N-acetylcysteine interact with medicines?
Adds to the effects of nitroglycerin (low blood pressure, headache). Can be taken with antibiotics but 2 hours apart.
Sources and further reading
Last reviewed 31 October 2026. Written by Satya Babu.
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