Cysteine is a semi-essential amino acid that your body can produce from other amino acids. It can become more essential if your diet is low in the amino acids methionine and serine. You can get cysteine from turkey, chicken, eggs, cheese, sunflower seeds, and supplements. N-acetyl cysteine is the supplemental form of cysteine.

N-acetyl cysteine is important to your health in a number of ways. This amino acid helps to replenish glutathione in your body. This is a powerful antioxidant that prevents damage to tissues and organs caused by free radicals and heavy metals. By fighting this oxidative damage, the risk of serious and chronic diseases is significantly reduced. N-acetyl cysteine is also important for respiratory, brain, and liver health. 

N-Acetyl Cysteine and Liver Health

Your liver plays an important role in digestion, as well as the detoxification of your body. Because the liver works to filter harmful toxins from your blood, it is exposed to an increased risk of damage from these toxins. The liver has mechanisms to protect itself, but chronic substance abuse, overuse of certain medications, and viral infections can put the organs in danger. 


A diseased liver will not function efficiently, which means digestion can be impaired, increasing your risk of metabolic disorders. In addition to this, a dysfunctional liver cannot properly filter the blood leaving increased levels of toxins in your body. Excessive damage from toxins causes scarring of liver tissue that cannot always be reversed or repaired. 

N-acetyl cysteine has been found to prevent liver damage and heal the damage caused by drugs and medications. Individuals treated with N-acetyl cysteine for an acetaminophen overdose showed significant improvement in survival rates. This supplement was also found to reverse liver failure caused by excessive alcohol consumption and exposure to pollutants. 

The ability of N-acetyl cysteine supplements to replenish glutathione levels also helps the liver with detoxification. Glutathione is a powerful antioxidant that fights free radicals and prevents damage to cells and tissues. This activity supports the liver as well as protects it from oxidative damage it may be exposed to. Glutathione also helps to make harmful compounds less toxic. 

The liver can also be damaged by chronic inflammation as a result of viral infections or autoimmune conditions. N-acetyl cysteine possesses strong anti-inflammatory properties that allow it to protect against the inflammatory response. N-acetyl cysteine modulates gene expression and inhibits the activity of pro-inflammatory chemicals in the body. As a result, inflammation is significantly reduced. 

Additional Health Benefits of N-Acetyl Cysteine

In addition to the essential role N-acetyl cysteine plays for liver and metabolic health, there are other important ways this amino acid supplement can boost your health and well-being.

Relieve Respiratory Conditions: N-acetyl-cysteine acts as both an antioxidant and expectorant. It works to loosen mucus in the airways, which relieves respiratory symptoms. As an antioxidant, N-acetyl cysteine replenishes glutathione levels in the lungs, which reduces inflammation. Individuals with respiratory conditions such as bronchitis and COPD (chronic obstructive pulmonary disease) experience chronic inflammation, and N-acetyl cysteine can relieve this. 

Boost Brain Health: N-acetyl cysteine regulates glutamate in the brain, an important neurotransmitter involved in learning and memory. It also replenishes glutathione, which protects brain tissues from oxidative damage. As a supplement, N-acetyl cysteine can benefit cognitive function by reducing brain cell aging. Parkinson’s disease and Alzheimer’s are associated with brain cell deterioration from oxidative damage. Studies show that N-acetyl cysteine may slow the loss of cognitive functions in these conditions. 

Reduce Risk of Heart Disease: Oxidative damage to heart tissues is one of the leading causes of heart disease and stroke. N-acetyl cysteine can reduce the risk of heart disease by actively fighting free radical damage. In addition to this, N-acetyl cysteine increases the production of nitric oxide. This compound improved blood flow by dilating veins, which can reduce the risk of a heart attack

Improve Immune Function: Supplementation of N-acetyl cysteine has been linked to improved immune system function. Studies involving patients with HIV have found that immune function is increased with natural killer cell production almost completely restored. Other studies have shown that N-acetyl cysteine can suppress the reproduction of certain viruses as well as block cancer cell replication. 

Taking N-Acetyl Cysteine

Your body can produce small amounts of cysteine, so there is no specific dietary recommendation for this amino acid. However, because a deficiency in this amino acid can increase the risk of serious disease, supplementation is recommended. 

a white egg next to a white egg and a white egg

N-acetyl cysteine has a low bioavailability, so when taken orally, the dosage should be between 600 and 1800mg. To help enhance the absorption of N-acetyl cysteine, your body requires adequate amounts of folate and vitamins B6 and B12. Any supplement taken needs to come from a high-quality source and contain clinically-proven ingredients. 

Side Effects and Warnings

N-acetyl cysteine is the supplemental version of an amino acid your body can produce. As a prescribed supplement, it is considered safe for adult consumption. There can be side effects associated with higher doses such as nausea, vomiting, diarrhea, and constipation. 

N-acetyl cysteine has also been shown to slow blood clotting. Individuals with a bleeding disorder or those scheduled for surgery should avoid taking this supplement. You should consult your doctor before taking N-acetyl cysteine supplementation as it can increase the risk of bleeding. 

The Bottom Line

Even though your body can produce cysteine in small amounts, N-acetyl cysteine supplements can be great for boosting your overall health. The deficiency of this amino acid can increase the risk of metabolic diseases, impaired liver function, and heart disease. By detoxifying the body and replenishing levels of the antioxidant glutathione, N-acetyl cysteine can protect you from oxidative damage and boost mental and physical well-being.