N-acetyl cysteine (NAC) is an amino acid that is most known for its antioxidant and anti-inflammatory benefits and is commonly used as an agent to help clear sinus and airway congestion caused by mucus overproduction. NAC is capable of reducing the viscosity of mucous and is also used to support respiratory and pulmonary health.
On the World Health Organization’s (WHO) list of essential medicines, NAC is a source of the conditionally essential amino acid L-cysteine and is a precursor to the tripeptide glutathione, an essential intracellular antioxidant. Glutathione is an important antioxidant used in many different metabolic processes within the body. Maintaining adequate levels is important to maintaining the health of the respiratory, hepatic and immune systems. It is also important in supporting antioxidant protection of lipids and proteins and supporting the normal response to inflammation. Glutathione is made inside cells and is not well absorbed by the body when taken orally. N-acetyl cysteine is one of the few antioxidants found to raise glutathione levels. In providing the necessary building blocks for its production, NAC has been shown to significantly increase glutathione levels therefore supports antioxidant and cellular detoxification pathways in the body.
In addition, a growing body of research also highlights the role of NAC in supporting neuropsychiatric health.
Detox and Liver Health
Though studies have shown the absorption of oral glutathione to be limited, supplementation with NAC has been shown to significantly increase circulating levels of glutathione in the body. Increasing glutathione levels in turn increases the production of specialized antioxidant enzymes such as glutathione peroxidase, glutathione reductase and detoxification enzymes such as glutathione S-transferases. Through the activity of these enzymes, NAC protects the body from oxidative damage, increases phase II detoxification, and enhances the normal breakdown of toxins and other metabolic byproducts of the body.
Breathing and Lung Health
Studies show NAC supports normal mucous production and may positively support pulmonary and respiratory function, especially when consumed over a prolonged period. A clinical trial of 100 smokers found NAC significantly improved measures of pulmonary health and high-dose NAC taken over a one year period resulted in significantly improved small airway clarity and decreased frequency of respiratory challenges. A systematic review found NAC to be effective in supporting children’s pulmonary health as well.
Mental and Brain Health
More recently, research has pointed to the role of NAC in targeting a diverse array of factors related to the neuropsychiatric health. NAC has been shown to protect neurons from oxidative damage, and to improve neurotransmitter production, mitochondrial function and inflammatory balance. Studies have also highlighted the role of NAC in modulating oxidative stress as its mechanism of action in neuropsychiatric health. In one 12-week, double-blind, randomized, placebo-controlled study of NAC in children with developmental delay, NAC resulted in significant improvements in irritability scores. Clinical trials studying the effects of NAC on a variety of psychiatric issues are ongoing.
NAC is a useful and safe supplement for a variety of conditions
Who should NOT take NAC??
N-acetylcysteine (NAC) has many antioxidant and anti-inflammatory health benefits, however…
Do not use NAC with:
- Previous signs of allergy to NAC. Reactions can be more severe in those with asthma.
- Organ transplant,
- a kidney condition called cystinuria, which indicates higher than normal levels of cysteine.
- High dose NAC has been documented to cause kidney stones.
- Those with severe liver and kidney disease will have much slower excretion
- Those with sulfa allergies may be more sensitive
Drug/Drug interactions can occur:
- NAC can reduce the excretion of various drugs (e.g., pravastatin, valsartan, erythromycin, torasemide, lovastatin, liothyronine, digoxin, cerivastatin, raloxifene, caspofungin, enalapril, simvastatin, penicillamine).
- The serum concentration of eluxadoline can be increased when combined with NAC.
- The therapeutic efficacy of NAC can be decreased when used in combination with oxytetracycline, trypsin, or tetracycline.