The Great Health Benefits of NAC (N-Acetyl Cysteine)

N-acetyl cysteine (NAC) is a synthetic form of cysteine, a semi-essential amino acid. When consumed, NAC breaks down into cysteine, which is metabolized to glutathione. Glutathione is a vital antioxidant for the proper functioning of the immune system and detoxification, as well as for the construction and repair of tissues. NAC is most valued for its ability to increase glutathione levels in the body and helps with various respiratory conditions, fertility, detoxification, and contributes to brain health.  1

N-acetyl cysteine (NAC) is the form of cysteine contained in dietary supplements. Cysteine is considered a 'semi-essential' amino acid because it can be produced in small amounts by the human body. Our bodies can normally produce cysteine from the amino acids serine and methionine. However, your body needs to have enough folate, vitamin B6 and vitamin B12 for this to be possible. That's why supplementation with N-acetyl cysteine is most often needed to get its many health benefits.

One of the most powerful roles of cysteine is related to the production of glutathione, the body's main antioxidant. Glutathione is essential for health. Cysteine is usually the amino acid that is in the shortest supply for glutamine production, so it's important to get enough of this amino acid, although it's not considered essential.

NAC maintains antioxidant activity by neutralizing hydrogen peroxide and the highly reactive hydroxyl radical and also serves as a source of sulfhydryl groups. In addition, NAC improves the production of the tripeptide glutathione, a key component of both antioxidant and detoxifying enzymes. NAC is known for its support for normal mucus production and can support respiratory function and eye health, especially when consumed for an extended period of time. 2

Other research suggests that NAC can protect cell and tissue health by maintaining normal mental status and helping to remove toxic metals into the body. 3

N-acetyl cysteine is an important part of detoxification. Various factors can determine glutathione needs, including level of toxin exposure, increased phase I detoxification activity, and overall need for antioxidant support due to increased stress levels. 

Once NAC promotes glutathione production, glutathione is incorporated into crucial antioxidant enzymes (e.g. glutathione peroxidase and glutathione reductase) and detoxification enzymes (glutathione S-transferases). Through the activity of these enzymes, glutathione directly supports antioxidant activity, phase II detoxification and the normal breakdown of metabolites, toxins and other compounds in the body. Glutathione is also involved in fatty acid synthesis and amino acid transport across the cell membrane. 4

NAC has the ability to regulate glutamate, the most important neurotransmitter in the brain. Glutamate is necessary for normal brain function. When the ability of NAC to replenish glutathione levels is combined, it makes N-acetyl cysteine a powerful tool for improving brain function. Research suggests that NAC may play a significant role in improving symptoms associated with brain and memory diseases, including Alzheimer's, Parkinson's and tremors. 5 Research is also looking at the potential of NAC for improvements in depression, bipolar disorder, schizophrenia, moderate to severe obstructive pulmonary disease, and reduction of withdrawal symptoms in cocaine addicts. 

The antioxidant and expectorant capacity of NAC may improve lung function by reducing inflammation as well as breaking down excess accumulated mucus. As an antioxidant, NAC can increase glutathione levels in the lungs, reducing inflammation in lung tissue and bronchi. N-acetyl cysteine therefore has applications to relieve nasal and sinus congestion symptoms due to allergies or infections, but also in more severe cases such as bronchitis and chronic obstructive pulmonary disease. 6

Increased levels of glutathione in the body improve immune function. Research on some diseases associated with NAC and glutathione deficiency suggests that immune function can be improved and potentially restored by supplementation with NAC. 7 

Cysteine is found naturally in meat, fish, grains, dairy, soybeans, and egg products, while the form NAC (N-acetylcysteine) is found in small amounts naturally only in some fruits and vegetables. Therefore, it is necessary to take it from other sources, including through a dietary supplement.