Benefits of N-Acetyl-l-Cysteine (NAC) as a Dietary Supplement

N-Acetyl-l-Cysteine, in short NAC, is a dietary supplement with powerful antioxidant benefits. Although most people are not familiar with NAC, it is extremely popular in the scientific community. It has been used as a drug since the 1960s and is listed on the World Health Organization (WHO) Model List of Essential Medicines as an antidote in poisonings[1]. NAC is used in food supplements and cosmetics due to its potent antioxidant effects. In recent years, it has gained popularity in the supplement realm and is regarded as a low-cost treatment protocol for various health conditions. 

What is N-acetyl cysteine (NAC)?
N-acetyl cysteine is a supplement form of the amino acid L-cysteine. Cysteine is an amino acid necessary for your body to make antioxidants, which protect your cells and tissue. While cysteine comes from many protein-rich foods, the NAC form can only be obtained from supplements or prescription drugs. NAC is an essential precursor for the production of glutathione, a powerful antioxidant produced by the body. When taken in a supplement form, it gets absorbed in the digestive tract and is sent to the liver. The liver converts NAC to cysteine, which is used to make glutathione. Glutathione derived from the amino acid cysteine is distributed from the liver to cells, tissues, and organs.

What does NAC do in your body?
One of the essential jobs of NAC is to help replenish the body's glutathione reserves. Glutathione helps fight free radicals, which are unstable molecules produced as byproducts of normal body functions like digestion, breathing, exercise, etc. When there are excess free radical generation or low glutathione reserves, it can be toxic to the tissues, cells, blood vessels, nerves, and the brain. Research reveals that increasing your body's antioxidant reserve and reducing free radicals have protective benefits. Boosting antioxidants helps lower your risk of developing chronic conditions such as heart disease and diabetes.

While this is one of the prime roles of NAC, it does more than just help your body's glutathione production. It is important to note that glutathione's powerful antioxidant effects and anti-inflammatory properties form the basis of NAC's beneficial effects. Below are some of the other vital benefits of NAC.

Top benefits of N-Acetyl-l-Cysteine (NAC)

The primary function of NAC is to help in glutathione formation.

Supports respiratory health: NAC has a low molecular weight; hence it is better absorbed via oral intake. Since it has a high affinity for lung tissue, it supports antioxidant action, lowers inflammation, and breaks down excess mucus production in the lungs. All these actions help improve better lung function. NAC is a mucolytic (mucous thinner)[2][3] and naturally works to reduce mucus secretions and phlegm. It is also helpful to relieve cough, wheezing, and troubled breathing. NAC supplements are beneficial for patients with chronic bronchitis[4], COPD, and emphysema. NAC improves glutathione levels in your lung tissues, which reduces inflammation in the bronchial tubes and the rest of your lungs, enabling better breathing. Studies link NAC intake to reduced incidence of nasal and sinus congestion due to allergies and infections[5]. Research shows that NAC supplements have improved conditions of exacerbation and lung decline in patients with COPD[6][7][8]. The American College of Chest Physicians and Canadian Thoracic Society recommend NAC therapy for moderate to severe COPD patients. They also recommended NAC therapy for the prevention of acute exacerbations of COPD. 

Boost brain health: NAC helps make glutathione which is a crucial antioxidant. Glutathione is essential for removing harmful free radicals from brain cells[9] and helps maintain cell health and integrity. A compromised brain cell health and integrity results in neurodegenerative diseases. Since glutathione production decreases with age[10], it is crucial to maintain an adequate level of this antioxidant. Taking sulfur-rich foods and including a NAC supplement is an excellent strategy to keep up with the body's glutathione levels. Optimal glutathione levels help reduce the risk of memory loss and age-related degenerative brain disorders. 

Stabilize blood sugar: Studies show that NAC can improve insulin action in response to blood glucose levels[11]. Preliminary studies have shown that NAC helps reduce inflammation in the fat cells, which influences insulin action. Ensuring adequate levels of glutathione ensures healthy insulin receptors. When insulin receptors are intact, they efficiently remove glucose from the bloodstream and keep blood sugar stable[12]. Although it is a conclusion from preliminary studies, and it is yet to be shown in human studies, the results are encouraging. 

Supports liver and aids detoxification: Before being used as a dietary supplement, NAC was first used in the medical world as an antidote for poisoning. Clinicians prescribe intravenous NAC to people with an acetaminophen overdose to mitigate kidney and liver damage[13]. NAC supplements are also widely suggested as adjunctive therapy in liver diseases[14]. Since liver diseases are often characterized by inflammation and oxidative damage, taking NAC supplements helps address the two issues and offer protective effects. 

Stabilizes mood: In addition to its brain-protective effects. NAC supplements are also found to enhance dopamine levels. Dopamine is a neurotransmitter that is responsible for focus and pleasure sensations in the brain. Also, NAC helps stabilize the levels of glutamate, a neurotransmitter. Excessive levels of glutamate paired with low levels of glutathione lead to brain damage and could contribute to conditions like depression, bipolar disorders, and schizophrenia[15].

Promotes healthy heart function: NAC helps promote heart health by protecting against oxidative damage to the heart and blood vessels. Oxidative stress is one of the causes of heart disease, stroke, blood pressure, and other severe conditions. A clinical study on heart patients found that low glutathione levels are related to poor heart function, including structural abnormalities of the heart[16]. This study shows that glutathione deficiency is related to heart problems, and blood glutathione tests may indicate heart abnormalities. Restoring optimal glutathione levels via food and NAC supplements could be an effective way to keep your heart healthy. 

Who should take NAC?

NAC is safe and can be taken as a dietary supplement by most people. You will also benefit from a NAC supplement if you-

  • suffer from blood sugar imbalances due to type 2 diabetes or insulin resistance.
  • have poor dietary habits and often eat unhealthily due to travel or work situations.
  • if you are an older adult with chronic health conditions.
  • an athlete or perform excessive physical activity.
  • consume excessive amount of alcohol.
  • if you suffer from frequent infection and low immunity.

NAC plays several vital roles in human health and is a viable option to prevent diseases as we age.

Here are some best NAC supplements to consider,

Thorne Research NAC: The formulation offers 500 mg of NAC in a capsule that is gluten and egg-free. A bottle of Thorne Research NAC (N-Acetylcysteine) contains 90 vegetarian capsules, with potent amino acid that increases glutathione levels (liver detoxification). In addition to supporting respiratory health, it also has kidney-protective effects. The supplement is also free of fillers, colors, and other artificial preservatives, and Thorne commits to 100% clean ingredients in all its formulation. The suggested dosage is one capsule two to three times a day or prescribed by your physician.

Integrative Therapeutics NAC 600 mg: The formulation offers 600 mg of NAC in gelatin capsules. Integrative Therapeutics NAC helps to replenish intracellular glutathione, which is vital in cellular antioxidant pathways. The recommended dosage is one capsule once or twice daily or as advised by your physicians.

Pure Encapsulations NAC 600 mg: This formulation offers NAC in a gluten-free, non-GMO, and hypoallergenic supplement. The supplement helps replenish body's glutathione levels for antioxidant protection and detoxification. It supports healthy respiratory function as NAC is a natural expectorant that loosens the mucus in your air passageways entering the lungs. Pure Encapsulations NAC supplements may help people with respiratory issues such as Each vegetarian capsule supplies 600 mg of NAC. The recommended dosage is 1 capsule once or three times a day between meals.

Pure Encapsulations NAC 900 mg: This is the same NAC formulation from Pure Encapsulations but at 900 mg of NAC per vegetarian capsule. The supplement caters to the needs of those seeking a higher dose of NAC in one capsule. One bottle of Pure Encapsulations NAC 900 mg supplies 120 vegetarian capsules. Note that recommended dosage is 1 capsule one or two times a day between meals.

Maintaining optimal glutathione is critical for protecting the body from toxins and improve health and longevity. NAC supplements appear to be a reliable way to boost the body's glutathione levels and derive robust health. Integrative Therapeutics takes pride in offering the best lineup of NAC supplements. We strive to provide the best and high-quality dietary supplements that meet standards.


[2]Henke MO, Ratjen F. Mucolytics in cystic fibrosis. Paediatr Respir Rev. 2007 Mar;8(1):24-9.
[3]Rogers DF. Mucoactive agents for airway mucus hypersecretory diseases. Respir Care. 2007 Sep;52(9):1176-93; discussion 93-7.