43 Benefits of NAC (N-Acetylcysteine)

January 30, 2019

NAC is an incredible antioxidant with numerous health benefits. It may help with mood disorders, sleep, infections, and inflammation. NAC protects the brain, gut, kidneys, liver, and lungs. It helps with most states of increased oxidative stress, which underlie chronic health problems. We list and describe all the benefits of NAC, along with dosage and side effects.

What Is NAC?

NAC is short for N-Acetylcysteine. NAC is transformed into cysteine in the body. Cysteine is the most important amino acid that makes glutathione, the body’s strongest antioxidant.

Cysteine levels determine how fast glutathione is made, NAC is essential in replenishing levels of this antioxidant in the body. Glutathione removes free radicals from cells and activates detox pathways.

NAC also falls under the category of “thiols”, antioxidant substances that contain the sulfur group. NAC is a thiol thanks to the sulfur-containing cysteine. In fact, this sulfur in cysteine is essential for the antioxidant activity of glutathione.

NAC can directly fight free radicals, acting as a powerful antioxidant.

Its antioxidant effects protect DNA, cells, tissues, and organs from damage, inflammation, and harmful substances.

NAC can also break down and soften mucus, which can improve lung diseases-

NAC has been thoroughly researched. The number of clinical, animal, and cell studies that explored the benefits of NAC are almost impossible to list. Close to a thousand clinical trials of NAC exist alone!

NAC Snapshot


Good for protecting the lungs, gut, brain, liver, and kidneys

Protects from many toxins and pollutants

Helps with obsessive-compulsive symptoms and addiction

Helps prevent the flu

Powerful antioxidant

Increases the master antioxidant Glutathione

Great biofilm disruptor

Improves fertility

Good for many chronic health problems


Doesn’t taste good and can cause a bit of nausea

May affect bleeding

Health Benefits of N-Acetyl Cysteine

NAC Protects the Liver

NAC boosts the antioxidant glutathione, the highest amount of which is in the liver. This helps explain why NAC has such a strong effect on protecting the liver from inflammation, drug poisoning, and serious liver diseases.

Liver inflammation

If the liver is damaged by any factor, inflammation and oxidative stress always rise. NAC can protect the liver by reducing inflammation and increasing antioxidant reserves.

NAC reduced liver damage in 85% of all cases, according to a review of 68 pre-clinical and 1 clinical study. It could protect the liver from factors such as excessive alcohol or environmental pollutants.

NAC helped increase liver function better than glutathione in one study of 75 patients with Hepatitis B. The patients received very high doses of NAC (8 g/day) as injections for almost a month.

Acetaminophen poisoning

N-Acetyl Cysteine has been used as an antidote to acetaminophen poisoning for over 50 years. Commonly-used painkillers (such as Tylenol and Vicodin) contain acetaminophen, which can damage the liver and even cause liver failure in high doses. It’s the most common cause of serious, sudden, liver damage.

N-Acetyl Cysteine is the most effective drug that can prevent serious liver damage from acetaminophen and increase survival, according to several studies of over 400 patients. NAC also has very few side effects.

Serious Liver Damage

Sudden, life-threatening liver damage can rarely also be caused by factors other than acetaminophen: various drugs, toxins, or hepatitis.

NAC helped protect the liver in 80 such cases (RCT), increased their survival and shortened their hospital stay. The patients with liver damage from drugs experienced the best results.

NAC has been studied a lot in the intensive care units, as a possible way to reduce organ damage before and after surgery. It helped protect the liver in 70 patients with lung disease, given shortly before heart surgery. 900 mg/day of NAC was given for a week.

NAC also reduced liver damage when given shortly before liver surgery in a study of 48 people (DB-RCT).

2) NAC Fights Free Radicals

Oxidative stress can damage cells and is increased in many chronic diseases, malnutrition, and toxin exposure.

NAC can replenish glutathione, protecting cells and organs that are under oxidative attack.

In several studies of 43 healthy men in total (RCTs), 1,200 mg of oral NAC daily increased antioxidant status after just 8 days. It increased the levels and activity of glutathione enzymes and reduced oxidative damage markers by more than 30%. NAC could also increase red blood cells and markers of their function and size (erythropoietin, hemoglobin, hematocrit, MCV)

Oral glutathione has poor bioavailability, and taking NAC is one way to circumvent this. Oral NAC (200 mg of power/day) increased glutathione and antioxidants better than oral glutathione in a study of 20 people. But sublingual glutathione had stronger effects than both NAC and oral glutathione after 3 weeks.

In African countries, children with severe malnutrition do not have good chances for survival. NAC could increase their recovery and survival by raising their glutathione levels in a pilot study. These children received up to 1,200 mg NAC/day in addition to standard treatment. Since NAC is cheap and safe option to aid their recovery by boosting antioxidant levels [R].

3) NAC Reduces High Homocysteine and Heart Disease Risk

B vitamins only somewhat help reduce high homocysteine, while NAC can lower both homocysteine and high blood pressure. Normalizing homocysteine could help prevent heart disease and other chronic health problems.

In two studies of 82 men in total (DB-RCTs), oral NAC (1,800 mg/day) lowered homocysteine and blood pressure while increasing antioxidant status over 4 weeks. It had an equally beneficial effect in men with high and normal blood lipids, and in both smokers and non-smokers.

In another study of 60 people with heart disease, NAC (600 mg/day) lowered homocysteine levels and improved blood vessel health over 2 months.

4) NAC Protects from Toxins and Pollutants

Glutathione is not stored only in the liver. By increasing levels of glutathione throughout the body and combating oxidative stress, NAC can protect from many toxins and pollutants.

Heavy Metal Exposure

NAC may be a safe alternative for chronic lead toxicity.

NAC reduced lead levels, increased glutathione and antioxidant enzymes in red and white blood cells in 171 workers exposed to lead after 3 months. It reduced both lead levels and homocysteine The beneficial daily dose was 400-800 mg per day.

The combination of NAC and zinc could also protect from mercury toxicity in rats, preventing the accumulation of mercury in the liver and blood.


NAC could help with pesticide poisoning by increasing glutathione and antioxidants, which helps the body and affected organs detox. NAC given to 30 people suffering from pesticide poisoning increased glutathione and reduced the need for additional treatments (RCT). Everyone received 1,200 mg NAC/day for only 3 days.

NAC also reduced the damage from a very toxic pesticide (aluminum phosphide) in one study (RCT). It reduced the hospital stay, improved breathing, and increased survival in those exposed to these pesticides.

Diesel Fuel

Exposure to diesel fuel can cause serious blood vessel damage, even in healthy people.

Taking NAC with vitamin C before diesel fuel exposure protected the blood vessels in one study of 21 people (DB-RCT). They took 1,200 mg of NAC the day before being exposed to diesel, and 1g of vitamin C daily for a week.

Diesel fumes can also cause breathing problems and worsen asthma. NAC (1,800 mg/day) over 6 days protected the airways and improved asthmatic symptoms in 26 people exposed to diesel (DB-RCT). It could reduce the need for asthma medications in this population.


Silica is often found on construction sites and in agriculture. It can cause serious lung damage. In 96 people exposed to silica, NAC (1,200 mg/day) combined with an anti-inflammatory improved lung function, coughing, pain, and congestion .

Chemical Warfare

NAC (1,200 mg/day) improved breathing, cough, congestion, and lung function in 144 people with poisoning from a chemical warfare agent (mustard gas). It was given over 4 months and had a very beneficial effect on oxidative stress (DB-CT).

Deadly Mushrooms

NAC can be a lifesaver when it comes to poisoning from Death Cap, the number one cause of fatal mushroom poisoning worldwide. NAC added to the anti-poisoning protocol enabled people to recover from the poisoning and prevent liver failure.

5) NAC Improves Lung Disease


NAC is commonly used to reduce the inflammation and mucus in people with lung disease, such as chronic bronchitis or Chronic Obstructive Pulmonary Disease (COPD). It can break down mucus and replenish glutathione in the lungs, which reduces airway damage and breathing difficulties.

In a review of 39 human studies, NAC can improve symptoms and prevent disease worsening in chronic bronchitis with no side effects. It needs to be taken for at least 3-6 months to achieve the respiratory benefits. Only 2 months of NAC, for example, did not improve COPD in one study of 51 people.

NAC combined with vitamin C increased the antioxidant and nutritional status in 79 people with COPD (RCT).

Even high doses of NAC (1,200 mg/day) given over 1 year were safe in a study of 120 COPD patients. NAC improved lung capacity, breathing, and prevented worsening.

NAC can also be given alongside oxygen, the typical COPD treatment. In 45 patients, it could prevent oxidative damage that can result from long-term oxygen treatment. NAC was given at the same time as oxygen at up to 1,800 mg/day for 3 days .

NAC could preserve lung function in 82 COPD patients who had to undergo heart surgery (DB-RCT).

Lung Damage and Infections

NAC had mixed effects on lung damage in two studies of 151 patients with a lung-scarring disease. In a smaller study of 28 patients, inhaled NAC could help those with milder forms of the disease. Oral NAC did not have the same benefits in the larger study.

Short-term, NAC (2400 mg/day) increased the level of vitamin C and antioxidant status in patients with a lung infection and scarring but didn’t improve lung function. It was given only for 30 days, which is probably not long enough to impact tissue regeneration

Inhaled NAC could also help with airway infections in a study of 100 small children.

6) NAC May Help Fight the Flu

Since NAC decreases the body’s inflammatory response, it may help prevent the flu or reduce symptoms of the common cold.

In one study of 262 older people, those adults taking NAC only developed the flu 25% of the time while those not taking NAC developed the flu 79% of the time. NAC could be especially helpful in the winter months when the flu season takes a hold.

NAC is also sometimes added on to standard treatments of sinus inflammation and infections, although the benefits are uncertain.

In cells, NAC reduced replication of the flu virus. If the virus can’t replicate quickly, it’s easier to fight it off.

7) NAC May Help Fight Addiction

It was first discovered that NAC has the potential for helping combat various types of addiction in animals. It could reduce binge eating in rats.

Cysteine from NAC seems to be able to enter the brain and normalize the neurotransmitter glutamate. Glutamate affects reward pathways involved in addiction, and NAC is able to re-balance its levels.

A large review of 165 patients and 9 studies found NAC especially useful for cannabis and cocaine addiction. NAC could also help with nicotine dependence, methamphetamine addiction, and pathological gambling.

It seems to also help some odd types of impulsive behaviors, such as hair pulling. NAC (1200-2400 mg/day) could reduce uncontrolled hair pulling in a study of 50 people with no side effects (DB-RCT).

Veterans with PTSD and addictions did a lot better after 8 weeks of NAC (2,400 mg/day) and psychotherapy (DB-RCT). NAC reduced overall symptoms, craving, and depression in all 35 veterans who participated.

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