Based on 10,000+ Reviews
Okendo Reviews Logo

What is N-Acetyl L-Cysteine (NAC)?

Benefits of NAC
N-Acetyl L-Cysteine

 What is N-Acetyl L-Cysteine (NAC)?

N-Acetyl L-Cysteine (NAC) is an acetylated conditionally essential amino acid. It can be made in the body. However, it becomes deficient under stress or when dietary intake of methionine and serine is inadequate. N-Acetyl L-Cysteine is a key amino acid along with L-Glycine and L-Glutamine in the production of Glutathione. Glutathione is our bodies most potent antioxidant and primary regulator of detoxification, immunity, and inflammation. So, boosting Glutathione levels has many positive benefits including antiaging. However, N-Acetyl L-Cysteine (NAC) has some incredibly well researched benefits beyond boosting Glutathione. Let’s take a deeper dive into these below…

A big reason N-Acetyl L-Cysteine (NAC) is so popular right now is because of its immune supporting and upper respiratory tract health benefits. NAC is an expectorant which loosen mucous that forms during upper respiratory illness. Its powerful anti-inflammatory benefits have been shown to reduce symptoms of COPD (Chronic Obstructive Pulmonary Disease).

A 1-year study of patients with COPD showed significant improvement in lung function after supplementation daily of 600mg of NAC. NAC may also reduce symptoms of bronchitis. Bronchitis occurs when membranes in your lungs become so inflamed, they swell and shut off the airways causing wheezing, coughing and respiratory attacks. Both NAC and Glutathione have been shown to support immune health. In fact, supplementation with NAC completely restores natural killer cell function in immune compromised individuals. In another study of patients with the flu, NAC was able to reduce the virus’s ability to replicate and reduced viral load which may reduce symptoms and length of the illness. In a recent study in Jan 2021 NAC was shown to cleave the disulphide bonds of the SARS CoV-2 spike protein as well as block the attachment to the ACE2 receptor which led to a 54.3% inhibition of viral replication. NAC has been shown to increase Natural Killer (NK) cells, B-Cells and T-Cells which make up your adaptive immune system allowing for rapid and effective termination of opportunistic pathogens.

NAC is a powerful antioxidant that clearly leads to its anti-inflammatory benefits. This also extends to fat cells. Obesity and high blood pressure cause oxidative stress and inflammation that may lead to insulin resistance.

NAC supplementation may stabilize blood sugar and improve insulin sensitivity by lowering inflammation in fat cells. In addition, NAC supplementation may improve heart health by reducing oxidative stress and improving NO2 (Nitric Oxide) production. NAC may also ameliorate the inflammation caused by oxidation and cytokines once the body is infected by a novel pathogen. This may reduce the symptoms of the pathogen considerably. Finally, as we said earlier… NAC helps make the bodies most potent anti-inflammatory and antioxidant called Glutathione.

NAC plays a critical role in detoxification. It has been shown to prevent the side effects of certain drugs, environmental toxins, pollutants, and heavy metals. It’s not uncommon for doctors to use NAC acutely to support liver and kidney health after toxicity occurs with overdose of acetaminophen (Paracetamol). NAC may also have further application for NAFLD (Non-Alcohol Fatty Liver Disease) and other hepatic disorders due to its powerful detoxifying and anti-inflammatory benefits.

NAC’s ability to replenish glutathione and regulate glutamate levels in the brain helps create a balance between glutamate and glutathione that may help support brain health, learning and memory.

Much of our age-related brain decline is due to oxidative stress over time. NAC’s may slow this decline by reducing the oxidative damage to cells in the brain responsible for the production and registering of neurotransmitters.

Approximately 15% of couples trying to conceive are burdened by infertility. One of the causes can be a condition called varicocele (where the veins of the scrotum become inflamed due to oxidative stress).

Patients with varicocele treated with surgery and NAC (600mg daily) had 22% higher pregnancy rates than the control group who didn’t receive NAC. Women with PCOS have a reduced fertility rate due to disrupted ovulation cycles. This may be due to inflammation and insulin resistance. NAC as part of a treatment protocol has been shown to induce ovulation which may increase pregnancy rates.


NAC is a potent antioxidant, anti-inflammatory and immune supporting amino acid. It’s a precursor to Glutathione and may benefit health and performance through many varied mechanisms. There is emerging evidence that NAC may also reduce muscle soreness and improve muscle recovery. It is also prescribed by Practitioners for the eradication of H-Pylori in the gut or as a mucolytic (reduces mucous build up) in the airways (lung and bronchus).

Dosing of between 600 – 1200mg twice daily with at least one serve at night (to support Glutathione production). The addition of vitamin C may help boost bioavailability. Side effects are rare if dosed appropriately but may include nausea, vomiting or diarrhea. People with blood clotting disorders, on blood thinning medication or having surgery should not consume NAC as it may slow clotting. NAC powder has a slightly sour bitter astringent taste that is best mixed in a fruity or citrusy flavoured drink to consume.

Disclaimer: The above article is merely a guide to inform about N-Acetyl L-Cysteine. It is based on peer reviewed research. However, it is in no way a recommendation or a treatment for any health conditions or diseases. You should always consult with your qualified health care provider before changing your supplement, training, or nutritional strategy. If you are using any prescribed medication, please check with your prescribing physician to see if NAC is right for you.