N- Acetyl-L-Cysteine is a specific form of sulfur-containing amino acids, which is commonly found in our body and in food proteins. Cysteine is part of human structural proteins, including skeletal muscle. Cysteine is a precursor of glutathione – one of the most important antioxidants, the strongest substance that protects our body against free oxygen radicals, many toxins and pathogenic agents. Glutathione supports, among others, removal of toxins from our body, regenerates damaged proteins and supports restoration of other antioxidants.NAC additionally has a mucolytic effect, i.e. it liquefies and reduces the viscosity of mucus, which has a beneficial effect in respiratory disorders because it facilitates the removal of excess mucus from the airways.

N-acetyl-cysteine also has a beneficial effect on the liver. It helps rebuild liver cells, improves liver function, prevents excessive liver damage and reduces liver damage caused by taking drugs, oral anabolic steroids or alcohol. In addition, it reduces toxic properties of heavy metals, accelerating their elimination from the body.

Additionally, it reduces inflammation in tissues and strengthens immunity by reducing oxidative stress, affects the production of proinflammatory cytokines and immune response, and antioxidant activity.N-acetyl-cysteine also found application in autoimmune diseases. The process of chronic inflammation and the oxidative stress associated with it are at the heart of auto-aggressive diseases, e.g. Hashimoto’s disease, multiple sclerosis, RA, inflammatory bowel diseases. The use of NAC can help reduce inflammation and slow down the autoimmune destruction of tissues.

Symptoms of N-acetyl-L- cysteine deficiencies:

L-cysteine deficiencies can lead to many free radical lesions, such as atherosclerosis, degenerative diseases, neurodegeneration and cancer.

The most common symptoms of L-cysteine deficiency are:

·       keratosis and other skin changes,

  • fragile hair,
  • split ends,
  • brittle and splitting nails.

Symptoms of excess amount of N-acetyl-L- cysteine:

Excess L-cysteine may be administered by taking unsuitable doses of supplements. It is associated with an increase in the level of homocysteine in the blood, which is a risk factor for heart disease, heart attack and stroke. 7 g of L-cysteine consumed at the same time are used as a lethal dose.

Symptoms of excess amount of these amino acids are as follows:

  • headaches,
  • nausea,
  • diarrhea.

Supplementation with N-acetyl-L- cysteine:

Supplements which contain N-acetyl-L- cysteine:

NAC N-Acetyl Cysteine 600mg (60 capsules) (Puritan’s Pride) – product available here

N-Acetyl-L-Cysteine 600 mg, 60 capsules (Life Extension) – product available here


People suffering from asthma, with bleeding disorders, excessive bleeding, peptic ulcer disease, respiratory failure and also with some methylation disorders should supplement it with caution.