What is NAC good for? (and How Much to Take?)


What is NAC good for?

NAC or N-Acetyl-Cysteine is good for the following:

  • It helps produce the antioxidant Glutathione in the body, thus helping to prevent cellular damage from free radicals. 
  • It helps to prevent or reduce kidney and liver damage by detoxifying and removing environmental toxins
  • Helps improve and treat mental conditions by regulating levels of the neurotransmitter glutamate. 
  • It improves the health of the respiratory system.
  • It helps to improve brain health and function such as memory, learning, and behavior.
  • It may help improve the fertility rate by improving semen quality in men and pregnancy rate in women. 
  • Improves immune function.
  • Decreases risk of heart disease.
  • It improves insulin sensitivity in PCOS patients.
  • It helps treat Acetominophen poisoning. 

How much NAC to take?

NAC has various uses, so how much NAC to take varies depending on the condition being treated. The typical dosage of NAC is between 600 mg to 1800 mg per day. 

  • For respiratory disorder: 600 mg/ day
  • For fertility: 600 mg/ day
  • Skin picking- 1200- 3000 mg/ day
  • For PCOS: 1800 mg/ day divided into three dosage
  • For COPD: 600 mg three times a day
  • For cystic fibrosis: 2400 mg/ day
  • For pulmonary fibrosis: 352.4 mg by inhalation
  • For myocardial infarction: 15000 mg over 24 hours through IV
  • For mental conditions: up to 2000 mg/ day
  • For paracetamol poisoning: 200 mg/ kg followed by 100mg/ kg IV 
  • For cough: 600 mg/ day

However, one should consult a physician before taking NAC, because a higher dosage of NAC can lead to severe adverse reactions.

In the video below, Dr. Eric Berg explains the benefits of NAC:

This is our recommended NAC supplement (Amazon’s Choice):

NOW Supplements, L-Cysteine 500 mg with Vitamins B-6 and C, Structural Support*, 100 Tablets

Does NAC supplement lighten the skin?

NAC supplement does help lighten the skin because the antioxidant glutathione stimulates a lighter version of melanin in the skin, making it appear bleached. 

In a study, mild to strong bleaching of skin was observed in 90% of women who were prescribed NAC and hydroquinone for a skin condition known as melasma.

Glutathione, an antioxidant produced by NAC inhibits the enzyme tyrosinase responsible for pigmentation. It helps reduce dark spots and brighten the skin. The antioxidant effect further reduces cell damage leading to wrinkles, inflammation, and pigmentation. 

A topical cosmetic preparation containing NAC was patented and marketed as a product for skin lightening as an alternative choice to cosmetics containing chemicals. 

What are the benefits of NAC for hair?

Following are the benefits of NAC for hair:

  • It may promote hair growth by providing essential nutrients. Hair contains about 14% L-cysteine, an amino acid that is derived from NAC. L-cysteine plays an essential role in hair formation and also prevents the breakage of hair strands. A study shows that oral administration of NAC for a phycological condition resulted in hair regrowth after 16 weeks of treatment.
  • NAC may also help in the healthy appearance of hair, prevent hair loss, and support faster hair growth. There are supplements marketed for the same claims. However, there are no clinical studies to validate these claims.  

Is NAC good for sleep?

NAC is good for sleep because it stimulates the production of neurotransmitter GABA which calms the mind helping with better sleep. It also increases the level of glutathione which may support longer and a night of better sleep. 

It also reduces mucus content in the throat, maintains airway clearance, and prevents mucus hypersecretion helping patients with obstructive sleep apnea to get a sound sleep. 

In a study, a 30 days treatment with NAC in patients with obstructive sleep apnea improved sleep and decreased apnea as compared to the control. 

Some experts suggest taking NAC for improving sleep instead sleep medications which may cause addiction. 

What is the dosage of NAC for OCD?

A review of clinical trials and case studies shows dosage of NAC for OCD is between 2400-3000 mg/ day for 3 months. 

Another case reports suggest a dosage of 1200-2400 mg/ day of NAC for the treatment of a type of OCD known as trichotillomania, where the patient compulsively tends to pull one’s hair. 

An undergoing clinical trial of NAC for pediatric OCD is using a dose ranging from 900 mg per day to thrice a day to evaluate its effectiveness. 

The possible mechanism of action of NAC in OCD is that it decreases the levels of the excitatory neurotransmitter glutamate in the brain and increases the level of dopamine. 

Is NAC good for treating allergies?

NAC is good for treating allergies because its antioxidant activity decreases oxidative stress and relieves allergic inflammation. 

A study shows that the antioxidant activity of NAC could be useful for the treatment of allergic asthma. 

NAC could also help with runny nose and cough by decreasing the thickness of mucus and clearing airway passage making the patient feel better. 

A study reports that NAC may have a role in affecting the cell death cycle of white blood cells in the blood, these cells play an important part in fighting allergic inflammation thus suggesting a possible role of NAC in treating allergies. 

Can you use NAC for the treatment of tinnitus?

NAC can be used for the treatment of tinnitus because it decreases the levels of the neurotransmitter glutamate in the brain. Glutamate is associated with promoting the degradation of neurons leading to the release of free radicals which further destroys neurons, and leads to loss of hearing and tinnitus. 

A study carried out on Swedish military personnel demonstrated that the administration of 400 mg of NAC after exposure to loud noises resulted in a significant reduction of noise-induced tinnitus as well as permanent hearing loss. 

People who benefited from NAC for the treatment of tinnitus have suggested a dosage of 600 mg of NAC for 10 days. 

Is NAC useful for acne?

NAC is useful for acne because its antioxidant and anti-inflammatory activity reduces oxidative stress and inflammation leading to a decrease in acne. It also reduces complications associated with acne and prevents the occurrence of another disease. 

In a study, researchers evaluated the effectiveness of different antioxidants including NAC on acne, after 8 weeks of treatment researchers found an almost 50% reduction in acne in patients treated with NAC. 

Studies suggest that a decrease in the level of glutamate and oxidative stress, an increase in the levels of glutathione, and detoxification are some possible mechanisms of action of NAC resulting in the decrease of acne. 

Can you use NAC for mucus?

NAC is useful for mucus because it helps break down and reduce the thickness of mucus helping clear airway passage. NAC works by breaking chemical bonds of mucus proteins resulting in its decreased thickness and easy clearance. 

Because of its ability to decrease mucus NAC is useful in the treatment of a multitude of respiratory and allergic conditions such as COPD, bronchitis, runny nose, wheezing, and coughing.  

NAC could be used orally or inhaled for treating mucus. Various clinical trials are underway for evaluating the effectiveness of NAC as a mucolytic agent. 

The suggested dosage of NAC for mucus is 5-10 ml of 10-20% solution every 6-8 hours or as needed. 

Is NAC supplement helpful for anxiety? 

NAC supplement can be helpful for anxiety because it increases the level of dopamine and promotes the release of GABA helping calm the mind. However, more clinical evidence is required to recommend NAC for treating anxiety. 

NAC is also found useful for the treatment of various forms of anxiety disorders such as OCD including compulsive hair pulling. 

A study suggests that NAC may offer some benefits to reduce anxiety symptoms in patients with OCD. 

The suggested dose of NAC for the treatment of anxiety is 600 mg twice or thrice a day. 

It is advised to start treatment with NAC at a smaller dosage or fewer times a day to avoid gastrointestinal distress. 

Can you use a NAC supplement for PCOS?

A NAC supplement can be useful for PCOS because it restores hormonal levels and the ovulation cycle. It further reduces oxidative stress and insulin resistance in women with PCOS. 

A study conducted to evaluate the effectiveness of NAC in patients with PCOS showed therapeutic effects and a decrease in the clinical symptoms similar to a typical drug treatment metformin. 

A meta-analysis of various studies involving eight clinical trials with 910 women for the treatment of PCOS, found that when women were treated with NAC the rate of live birth and spontaneous ovulation increased compared to placebo. The study did not find any adverse effects related to NAC supplementation.

Is NAC supplement helpful for skin picking?

NAC supplement can be helpful for skin picking because it restores the level of a neurotransmitter known as glutamate, which plays an important part in OCD. 

A clinical trial was conducted on 66 individuals suffering from skin picking. The subjects were treated with either NAC or placebos. 1200-3000 mg/ day of NAC was administered to the patients for 12 weeks. The trial demonstrated that the treatment with NAC resulted in a significant reduction in skin picking as compared to placebos. 

A case study also showed that the addition of NAC to the existing medication improved patient conditions significantly.

Can you use NAC for thyroid treatment?

NAC can be useful for thyroid treatment because it restores levels of thyroid hormone and decreases oxidative stress in the body. The antioxidant activity of NAC helps maintain higher levels of glutathione leading to optimal levels of thyroid hormone in the body. 

Thyroid glands in the process of producing thyroid also produce free radicals. These free radicals are neutralized by glutathione which otherwise may lead to tissue damage. 

The maintenance of minimal oxidative load by glutathione is also responsible for the better functioning of thyroid glands. 

The antioxidant activity also reduces the levels of thyroid antibodies, higher levels of which may affect the functioning of thyroid glands. 

Is NAC supplement useful for autism?

NAC supplement can be useful for autism because it decreases its symptoms. A meta-analysis of four controlled trials shows that after 8-12 weeks of supplementation with NAC the symptoms of autism were decreased. The children in the trial showed decreased irritability, lowered hyperactivity, and increased social awareness. During the trials, NAC was found to be safe and tolerable.

A case report where an eight-year-old child underwent autism treatment with NAC suggests that NAC could be potentially used for the treatment of autism. 

However, more clinical evidence is required before it can be used for the treatment of autism. 

What are the side effects of NAC supplements?

Although NAC supplements are well tolerated and safe to use, they may show some side effects in some people.

  • At higher dosages nausea, vomiting, and constipation. 
  • People on blood-thinning medication should not take NAC because it may slow down blood clotting.
  • On inhalation, it may cause drowsiness, swelling in the mouth, runny nose, and tightening in the chest. 
  • In some people, it may cause gastrointestinal disturbances. 
  • IV infusion may cause an anaphylactic reaction, hypotension, and bronchial spasm.
  • It may cause eye irritation, fatigue, and diarrhea.  
  • In some people, it may cause headaches, low blood pressure, and an asthma attack. 
  • Fever, hives, itching, skin rash
  • Reddening around ears.
  • Weakness.

Should you take NAC with or without food?

NAC is recommended to be taken on an empty stomach or without food to ensure better absorption. In addition, NAC has low bioavailability and it may compete with other proteins for absorption hence it is suggested to take NAC without food. The suggested time for taking NAC is 30 minutes before breakfast or 2 hours after dinner.

Since NAC has a strong odor some people advise against taking NAC just before bedtime because it may not be pleasant. 

However, it is applicable only for oral administration of NAC, for inhalation or IV route the presence of food does not matter.  

Can you take NAC before bed?

NAC can be taken before bed or 2 hours after dinner depending on the condition. It is beneficial to take NAC before bed if it is being used to treat lung conditions, since disorders associated with lungs tend to get worse at night time due to mucus build-up. 

Taking NAC before bed gives it the time required to start working, so it can ensure good sleep and clear airway passage during the night. 

However, due to the strong odor of NAC, taking it before bed may not be ideal for some people. 

Is NAC supplement banned by FDA?

As of March 31st, 2022 NAC is banned by FDA as a supplement. FDA has decided to exclude NAC from the list of dietary supplements because it is already approved as a drug. However, the agency says it is working on guidelines for NAC to be used as a dietary supplement or as a part of dietary supplements. 

The agency further added that during the initial review it did not find any health and safety concerns for NAC as a dietary supplement or as an ingredient of a supplement. It also mentioned that the product has been in use as a supplement for over 3 decades, however, a thorough review may take time. 

How long does NAC take to work?

NAC takes about 1-2 hours to work after administration because it needs to be converted to glutathione to start working. The person can expect to see improvement in the condition after 1-2 hours of oral administration.

To decrease oxidative stress, it may take up to a week to show results. For the treatment of conditions such as OCD, it may take as long as 16 weeks. 

Also, the time required to work is dependent on the route of administration as well. Treatment with an IV infusion starts working faster than the oral dose. 

For treatment of paracetamol poisoning IV administration of NAC shows the peak concentration in the blood within 15 minutes.

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This article makes use of information from the U.S. National Library of Medicine under the terms of the Creative Commons Attribution 4.0 International License.

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What is NAC good for? (and How Much to Take?)
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