NAC (N-acetylcysteine)
N-acetyl-L-cysteine
Supplements. Modern nutrition.
Also called Acetylcysteine, N-acetyl cysteine
Pinyin: yǐ xiān bàn guāng ān suān
Spanish: N-acetilcisteína
Interacts with nitroglycerin and charcoalA modified form of the amino acid cysteine, sold to help the body make glutathione and to loosen mucus.
Did you know? Doctors found in the late 1970s that NAC could protect the liver from a Tylenol (acetaminophen) overdose.
What it may help, and how strong the proof is
- Breathing & asthma. In chronic bronchitis and COPD, some trials show fewer flare-ups with NAC. Other trials found no benefit, so results are mixed.Early proof
- Liver. Hospitals give IV NAC for acetaminophen overdose. Taking NAC by mouth to protect the liver in healthy people has little proof.Traditional proof
Parts of the body
Traditional use
NAC is a modern medicine, not an herb with folk use. It was first used as a mucus thinner and later as a hospital antidote.
How it is classified
- Herbal actions
- Expectorant, Antioxidant, Hepatic. Energy: neutral.
How people take it
Lung studies used 600 mg once or twice a day, and some used 1,200 mg a day. Take it with water or a meal to reduce stomach upset. Do not use it in place of prescribed medicine for an overdose or lung disease.
Capsule, powder and tablet.
Where to get it
NAC is made in labs from the amino acid cysteine, which the body also gets from eggs, poultry and whole grains. It is sold as capsules, powders and tablets in stores and online.
Be careful
Common side effects are nausea, stomach upset and a sulfur smell. It can increase the blood pressure drop from nitroglycerin, and charcoal can reduce how much NAC you absorb. Pregnancy data are limited, and people with asthma should check with a doctor first.
Avoid if: pregnancy; asthma.
Mixing with other things
- Works well together
NAC supplies cysteine, a building block the body uses to make glutathione.
- Use cautionHeart rhythm medicine (digoxin, amiodarone)
May increase the blood pressure drop from nitroglycerin.
- Use caution
Charcoal can lower how much oral NAC the body absorbs.
The honest take
The strongest proof is for hospital IV NAC used for acetaminophen overdose, which is a medical use. For lungs, results from oral trials are mixed, and it is not a substitute for usual COPD care. Most other claims for NAC remain unproven in people.