NAC (N-acetyl cysteine) is an altered form of the amino acid cysteine, which is commonly found in food and synthesised by the body. It is not a true nutrient and cannot be obtained from food, it is only found in food supplements. NAC has the ability to produce the antioxidant enzyme glutathione peroxidase.

What it does

  1. Liver Protectant: Glutathione is required for the detoxification of toxins by the liver. NAC has been shown to be the most effective method of increasing glutathione levels. NAC is often administered in the early stages of paracetamol poisoning.
  2. Detoxifier: NAC is one of the most effective methods of elevating glutathione, required for liver detoxification.
  3. Heavy Metal Scavenger: It is able to bind to heavy metals, thus aiding their removal from the body.
  4. Antioxidant: NAC, both alone and as part of glutathione, is a very effective free radical scavenger. It is especially valuable in protecting cell membranes.
  5. Cardiovascular Protectant: NAC can prevent oxidation of LDL cholesterol, a known risk factor in heart disease. NAC also significantly lowers lipoprotein A, which appears to be an even greater risk factor in heart disease than cholesterol.
  6. Respiratory Support: NAC breaks up bonds that account for the thick consistency of mucous, thus aiding its removal. NAC may help dissolve mucus and improve symptoms associated with chronic bronchitis, asthma, cystic fibrosis and emphysema. Chronic smokers also may benefit from NAC supplementation due to its antioxidant properties (cigarette smoke is a significant source of free radicals)
  7. Anti-Viral: NAC increases glutathione levels in virally infected cells more efficiently than taking glutathione itself. Raised cellular glutathione inhibits viral spread.

Potential Uses

Liver protection Emphysema Cystic fibrosis
Heavy metal poisoning Chronic obstructive pulmonary disease Bronchitis
Paracetamol poisoning Atherosclerosis Asthma
Cigarette smokers


Generally, there are no side effects or contra-indications from using NAC.

Vitamin C supplementation is often recommended when taking 1-cysteine.

If you take metoclopramide or use nitroglycerine, consult your doctor before taking NAC.

Do not use in pregnancy or when breastfeeding.

Cysteine may produce a false positive in diabetic tests for ketone bodies.

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