N-Acety-L-Cysteine (NAC)

General Info


N-Acety-L-Cysteine (NAC) is easily absorbed from the intestinal tract.

Dietary Origins

NAC does not occur in foods. Its original, L-cysteine, occurs in most high-protein foods.


NAC is a derivative of the amino acid, L-cysteine, a building block of protein. The activity of NAC is linked to its conversion to glutathione, a potent antioxidant. As an antioxidant that has been used to combat viruses, and helps the liver detoxify a wide range of pollutants such as auto exhaust, certain fungicides, cigarette smoke, and some toxic metals through improving phase II detoxification mechanisms in the liver. The underlying cause of many diseases not associated with infection results from a problem with protein and amino acid assimilation.

Toxicities & Precautions


NAC is considered very safe. When NAC is used at high doses, over 20 grams a day, to treat acetaminophen poisoning, urinary zinc excretion may occur, in which case it may be necessary to monitor zinc and copper levels.

Side Effects

Although side effects are very rare, varying degrees of nausea, vomiting, headache, dry mouth, dizziness, or abdominal pain may occur with high doses.

Functions in the Body


NAC acts as an antioxidant. NAC is the direct precursor of glutathione, which is also a part of the body's antioxidant defense system.

Heavy Metal Detoxifier

NAC is able to combine and detoxify heavy metal toxins such as mercury and arsenic.

Symptoms & Causes of Deficiency

N-Acety-L-Cysteine is not an essential nutrient for humans and a deficiency condition has not been identified. However, based on what is know about NAC’s functions in the body, it could be speculated that a deficiency could result in decreased glutathione levels, increased inability to detoxify heavy metal toxins, elevated lipoprotein, and increased risk of hydrogen peroxide damage.