What is NAC (N-Acetyl Cysteine)?

N-acetyl cysteine (NAC) comes from the amino acid L-cysteine. Amino acids are building blocks of proteins.

What is NAC found in?

N-Acetyl Cysteine (NAC) is found in various dietary sources, including foods rich in protein such as poultry, eggs, yogurt, and cheese. It is also available as a dietary supplement.

What are the benefits of NAC?

N-acetyl cysteine is an antioxidant that might play a role in preventing chronic disease. As a drug, it is used in emergencies in the case of paracetamol poisoning. It works by binding the poisonous metabolites of paracetamol that are formed in the liver [i].

Detoxification: Glutathione support to support immune function

NAC is essential in supporting the powerful antioxidant, glutathione. Glutathione is one of the body’s most important antioxidants, which helps neutralise free radicals that can damage cells and tissues in your body. It is essential for immune health and preventing cellular damage [ii]. Therefore, NAC is mainly valued for its antioxidant potential.

Research suggests that NAC may be beneficial in reducing the inflammation in the lungs from RNA viruses and boost the body’s ability to create antibodies against these viruses. The researchers conclude that these compounds may indeed, “help provide relief to people infected with encapsulated RNA viruses such as influenza and coronaviruses.” [iii].

Respiratory conditions

As an antioxidant, NAC replenishes glutathione levels in the lungs and reduces bronchial (airway) inflammation and inflammation of the lung tissues.

Chronic obstructive pulmonary disease (COPD) disease involves long-term oxidative damage and inflammation of lung tissue, causing airways to constrict and leading to shortness of breath and coughing. NAC supplements have been used to improve COPD symptoms, exacerbations and lung decline [iv] [v].

In the case of bronchitis, NAC may help decrease the severity and frequency of wheezing, coughing and respiratory attacks by thinning mucus in the bronchial tubes and boosting glutathione levels [vi]. In this way, NAC may also alleviate other respiratory tract conditions like cystic fibrosis, asthma and pulmonary fibrosis, as well as symptoms of nasal and sinus congestion due to allergies or infections [vii].

Brain health

NAC helps regulate levels of glutamate, an excitatory neurotransmitter that promotes activity in the brain [viii]. For this reason it is thought to be effective in disorders such as OCD and addictive behaviours, with evidence from clinical studies to this effect [ix] [x].

Results also show promise in children with ADHD [xi] [xii]. Taking N-acetyl cysteine by mouth might also improve irritability in children and adolescents with autism [xiii].

NAC may also support ageing and help to prevent age-related diseases such as Parkinson’s. Parkinson’s disease, is characterised by the deterioration of cells that generate the neurotransmitter, dopamine. Both oxidative damage to cells and a decrease in antioxidant ability contribute to this disease. NAC supplements appear to improve both dopamine function and disease symptoms such as tremors[xiv].

Other age-related conditions such as memory loss and Alzheimer’s have shown improvement with use of NAC in animal studies [xv] [xvi].

Fertility

NAC may be beneficial for improving fertility in both men and women, by reducing oxidative damage in the reproductive systems. In one study, 35 men with varicocele were given 600 mg of NAC per day for three months post-surgery. The combination of surgery and NAC supplement improved semen integrity and partner pregnancy rate by 22% compared to the control group [xvii].

In women with polycystic ovary syndrome (PCOS), NAC may improve fertility by inducing the ovulation cycle [xviii].

Blood sugar balance

Damage to fat cells via high blood sugar and obesity contribute to inflammation in fat tissue. This can lead to damage or destruction of insulin receptors and increase type 2 diabetes risk. Animal studies show that NAC may stabilise blood sugar by decreasing inflammation in fat cells and thereby improving insulin response to enhance the body’s natural response to increased blood sugar from a meal [xix] [xx].

Heart disease and cholesterol

Oxidative damage to heart tissue often leads to heart disease. This can lead to strokes, heart attacks and other serious cardiovascular-related conditions. NAC may reduce heart disease risk by reducing oxidative damage to tissues in the heart.

Taking N-acetyl cysteine by mouth seems to reduce levels of a blood fat called lipoprotein(a) in people with high levels of blood fat. A test-tube study showed that, when combined with green tea, NAC appears to reduce damage from oxidised “bad” LDL cholesterol, another contributor to heart disease [xxi] .

Safety

Bleeding disorder

N-acetyl cysteine might slow blood clotting. N-acetyl cysteine might increase the risk of bruising and bleeding in people with bleeding disorders.

Surgery

N-acetyl cysteine might slow blood clotting. This might increase the risk of bleeding during and after surgery. It is recommended to cease taking N-acetyl cysteine at least 2 weeks before a scheduled surgery.

Interactions

Nitroglycerin can dilate blood vessels and increase blood flow. Taking N-acetyl cysteine seems to increase the effects of nitroglycerin. This could cause increased chance of side effects including headache, dizziness, and lightheadedness.