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N-acetyl cysteine(NAC): Amino Acid Protector

NAC is a type of cysteine that is taken as a supplement.
NAC Amino Acid Protector


Antioxidant N-Acetyl-Cysteine (NAC) is a precursor of glutathione, the body’s most potent natural antioxidant. Glutathione is considered the “master antioxidant” because, unlike all the other antioxidants, it doesn’t need any other antioxidant to help it do its job.

Key Benefits

NAC has been shown to:

  • Provide antioxidant protection
  • Support immune function 
  • Replenish the body’s endogenous glutathione levels
  • Support lung health by breaking up mucus
  • Encourage healthy liver function
  • Support memory and brain function
  • Provide anti-aging properties
  • Prevent flu-like symptoms in the elderly and those at high risk.
  • Remove mercury from the blood
  • Increase nitric oxide production
  • Lower homocysteine levels
  • Improve impaired blood flow in smokers
  • Reduce inflammation
  • Suppress viral replication
  • Help support sperm quality

History of Usage

NAC (N-acetyl cysteine) is one of the best-researched amino acids.  It was first used as an antioxidant antidote to acetaminophen overdose.  Acetaminophen, the over-the-counter pain reliever, can cause severe liver damage in high doses, and NAC is the best antidote to prevent this damage. It was then developed as a therapeutic for its ability to break up mucus in the lungs in conditions like bronchitis. Throughout the many decades of research, researchers have discovered that NAC, being an amino acid protector, has great potential for preventing heart disease, memory loss, cancer, and also the ability to raise glutathione levels in the body, which is significant since glutathione is one of our body’s most important antioxidants.


This synthetic N-acetyl derivative of the endogenous amino acid L-acetylcysteine has mucolytic, antioxidant, cytoprotective, cancer-preventive, antiviral, and anti-inflammatory properties.

NAC exerts its mucolytic effect by eliminating disulfide linkages in mucoproteins, hence liquifying and decreasing the viscosity of mucus. It is also used to treat acetaminophen overdose, as it can replenish the hepatocytes’ depleted GSH reserves during the detoxification process. The antioxidant activity of GSH is a result of its ability to scavenge reactive oxygen species (ROS), consequently avoiding ROS-mediated cell damage, reducing oxidative stress, shielding cells from free radical damage, and preventing apoptosis in these cells. Additionally, this may decrease tumor cell proliferation, progression, and survival in tumor cells vulnerable to ROS-mediated signalling for proliferation and malignant activity.

NAC may also inhibit viral stimulation by reactive oxygen intermediates. It also possesses anti-inflammatory activity through modulation of the nuclear factor-kappa B (NF-kB) pathway and the modulation of cytokine synthesis.

Extracellular ROS scavenging, replenishment of intracellular GSH, and T cell protection are all potential therapeutic effects of NAC, which may help to alleviate inflammation and tissue damage.

Recent Trends

NAC is affordable, has a low toxicity profile, has been approved by the FDA for several years, and has the potential to improve therapeutic techniques for infectious disorders, including SARS variants. NAC given intravenously, orally, or breathed may reduce virus replication and improve results. Combining NAC with other antiviral medications may reduce hospitalization, mechanical ventilation, and mortality.

NAC supplements are widely available and can be purchased at health food stores and pharmacies. It is used in intravenous and oral forms in the hospital to protect and restore the body before and after it has been exposed to certain chemicals, including the radioactive dyes used for MRIs and in the case of acetaminophen overdose. It is also used to help cancer patients cope with the side effects of isoffamide and cyclophosphamide.

Isoffamide and cyclophosphamide-related side effects can be alleviated in certain patients with the use of this drug. In 2027, the N-acetylcysteine market is expected to reach a value of over USD 2.2 billion, with a CAGR of 21% from 2020 to 2027.


  • Women who are breastfeeding should not take NAC.
  • Individuals who are taking Nitroglycerin should not take NAC.
  • Individuals who take blood thinning medications should not take NAC.
  • Asthma: Inhaling or ingesting N-acetyl cysteine may cause bronchospasm in asthmatics. Patients with asthma who take N-acetyl cysteine should be closely watched by their doctor.
  • Bleeding disorder: N-acetyl cysteine may help blood clot more slowly. In persons with bleeding disorders, N-acetyl cysteine may increase the risk of bruising and bleeding.
  • Surgery: N-acetyl cysteine may help blood clot more slowly. This may result in an increased risk of bleeding during and following surgery. At least two weeks before the  scheduled surgery, discontinue taking N-acetyl cysteine.
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  14. Product Information: ACETADOTE(R) intravenous injection, acetylcysteine intravenous injection. Cumberland Pharmaceuticals Inc. (per FDA), Nashville, TN, 2016.
  15. Product Information: CETYLEV oral effervescent tablets for solution, acetylcysteine oral effervescent tablets for solution. Arbor Pharmaceuticals (per FDA), Atlanta, GA, 2016.