NAC (N-Acetyl Cysteine) is an incredible antioxidant with numerous health benefits. It may help with mood disorders, sleep, infections, and inflammation, and more. It boosts your glutathione levels and helps with most states of increased oxidative stress that underlie chronic health problems. Read on to uncover all its benefits, along with dosage and side effects.
What Is NAC?
NAC (short for N-Acetyl Cysteine) is transformed into the amino acid cysteine in the body. Why should you care about cysteine?
In other words, if glutathione is “the mother of all antioxidants,” then cysteine would be the grandmother.
Since cysteine levels can determine how much and how fast glutathione is made, NAC is essential in replenishing levels of this antioxidant. Glutathione (specifically reduced glutathione or GSH) removes free radicals from cells and activates detox pathways [R, R].
The cysteine also contains sulfur, which is essential for glutathione to work [R].
But that’s not all.
Aside from boosting glutathione, NAC can directly fight free radicals [R].
Its antioxidant effects protect DNA, cells, tissues, and organs from damage, inflammation, and harmful substances. For this reason, its benefits range from brain protection to liver support to balancing mood. NAC can also break down and soften mucus, which can improve symptoms of lung diseases [R, R].
Importantly, 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!
- Powerful antioxidant
- Increases Glutathione
- 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
- Great biofilm disruptor
- Improves fertility
- Helps with many chronic health problems
- Doesn’t taste good and can cause a bit of nausea
- May affect bleeding
Health Benefits of N-Acetyl Cysteine
1) Protects the Liver
NAC boosts 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.
If the liver is damaged, 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 large review. It could protect the liver from factors such as excessive alcohol and environmental pollutants [R].
Interestingly, NAC injections helped increase liver function better than glutathione in one study of 75 patients with Hepatitis B [R].
N-Acetyl Cysteine has been used as an antidote to acetaminophen poisoning for over 50 years.
Commonly-used painkillers (such as Tylenol) contain acetaminophen, which can damage the liver and even cause liver failure at high doses. Acetaminophen is the most common cause of serious, sudden, liver damage [R, R].
Sudden, life-threatening liver damage can also be caused by various drugs, toxins, or hepatitis.
NAC helped protect the liver in 80 such cases. Patients with liver damage from drugs experienced the best results [R].
NAC has been studied a lot in intensive care units, as a possible way to reduce organ damage before and after surgery [R].
Although NAC can help repair serious liver damage, it can also offer less drastic benefits for detox or liver support. It increases glutathione in the liver and helps to prevent liver damage from toxins, drugs, and pollutants.
2) Fights Free Radicals
Excessive oxidative stress can damage cells and underlies many chronic diseases, malnutrition, and toxin exposure. By replenishing glutathione, NAC can protect cells and organs that are under oxidative attack [R].
But that’s not all.
You may think that you’d be better off supplementing with glutathione if the main benefit of taking NAC is boosting this antioxidant. However, it’s not that simple.
Oral glutathione has poor bioavailability, and taking NAC is one way to circumvent this. NAC increased glutathione levels and other antioxidants better than glutathione supplements when taken orally in a study of 20 people. But sublingual glutathione (which is not widely available) had stronger effects than both NAC and oral glutathione after 3 weeks. In addition, liposomal glutathione is effective at raising bodily levels of glutathione. As of the publication of this article, no studies have been done comparing the bioavailability of NAC and liposomal glutathione [R, R].
NAC may also help children with malnutrition in developing countries.
In African countries, children with severe malnutrition have a very poor prognosis. NAC could increase their survival by raising their glutathione levels in a pilot study. It may be a cheap and safe option to aid recovery in people with severe nutritional deficiencies [R].
3) Reduces High Homocysteine and Heart Disease Risk
B vitamins only somewhat help reduce high homocysteine. On the other hand, NAC can lower both homocysteine and high blood pressure, which helps prevent heart disease and other chronic health problems [R].
In two studies of 82 men, oral NAC 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 [R].
In another study of 60 people with heart disease, NAC lowered homocysteine levels and improved blood vessel health over 2 months [R].
To sum it up, supplementing with NAC protects the heart. It lowers homocysteine, prevent high blood pressure, and potentially reduce the risk of heart disease.
4) 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 toxins and pollutants.
Heavy Metal Exposure
NAC may be a safe alternative for chronic lead toxicity.
The combination of NAC and zinc could also protect from mercury toxicity in rats, preventing the accumulation of mercury in the liver and blood. Clinical studies would need to confirm this effect [R].
NAC also reduced the damage from a very toxic pesticide (aluminum phosphide) in one study. It shortened the hospital stay, improved breathing, and increased survival in people exposed to these pesticides [R].
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 [R].
Diesel fumes can also cause breathing problems and worsen asthma. NAC over 6 days protected the airways and improved asthmatic symptoms in 26 people exposed to diesel, reducing their need for asthma medications [R].
Silica is often found on construction sites and in agriculture. It can cause serious lung damage. In 96 people exposed to silica, NAC combined with an anti-inflammatory improved lung function, coughing, pain, and congestion [R].
NAC improved breathing, cough, congestion, and lung function in 144 people with poisoning from a chemical warfare agent (mustard gas) [R].
NAC can be a lifesaver in people who ingested Death Cap, the number one cause of fatal mushroom poisoning worldwide. ANAC added to an anti-poisoning protocol, it enabled people to recover from the poisoning and prevented liver failure [R].
5) 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 [R].
According to a large review, NAC improves symptoms and prevents disease worsening in people with chronic bronchitis with no side effects. It needs to be taken for at least 3 – 6 months, as 2 months of NAC did not improve COPD in one study [R, R].
Combined with vitamin C, NAC increased the antioxidant and nutritional status in 79 people with COPD [R].
High doses over 1 year were safe and improved lung capacity and breathing in people with COPD in another study [R].
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 [R].
All in all, people with chronic bronchitis or COPD may benefit from NAC. Supplementation can improve lung function, prevent disease worsening, and soften mucus.
Lung Damage and Infections
NAC will not have the same respiratory benefits in people with lung scarring or lung infections.
It 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 [R, R].
Short-term, NAC 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 [R].
Inhaled NAC also helped with airway infections in a study of 100 small children [R].
6) 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 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 [R].
In cells, NAC reduced replication of the flu virus. If the virus can’t replicate quickly, it’s easier to fight it off [R].
7) 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 [R].
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 [R, R].
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 [R].
It seems to also help some odd types of impulsive behaviors, such as hair pulling. NAC could reduce uncontrolled hair pulling in a study of 50 people with no side effects [R].
Veterans with PTSD and addictions did a lot better after 8 weeks of NAC and psychotherapy. This approach reduced overall symptoms, craving, and depression [R].
NAC helped reduce craving in 23 people with methamphetamine addiction [R].
But in another study, NAC combined with an opioid blocker (naltrexone) did not show any benefits in 31 people with methamphetamine addiction [R].
More research is needed.
When it comes to cocaine dependence, NAC may help reduce craving and relapse.
In one study of 111 people, NAC helped maintain abstinence from cocaine over 8 weeks [R].
NAC also helped reduce cocaine desire in 15 people after just 3 days [R].
When 8 people with cocaine dependence were given NAC and taken to a brain scanner, their brain glutamate levels went down. NAC didn’t demonstrate this effect in 14 healthy people under the same conditions. This suggests that NAC can specifically lower abnormally increased glutamate in people with addiction [R].
People addicted to cannabis who try to quit may revert to overdrinking. In 302 people addicted to cannabis, NAC could reduce alcohol consumption by 30% in those trying to quit [R].
In another study, however, NAC had no effect on cannabis addiction in adults [R].
Women heavily dependant on cannabis tend to have more problems quitting and experience mental health struggles. This is why NAC may only affect men, whereas women would need additional treatment for low mood and anxiety [R].
In 116 marijuana-dependant teenagers, those taking NAC used marijuana and alcohol less frequently. Since NAC is very safe, it could be helpful for adolescents suffering from alcohol and cannabis overuse [R].
Several studies are still exploring the effects of NAC on cannabis addiction [R].
One study on almost 100 people confirmed that smokers have higher brain glutamate levels [R].
In 16 smokers, NAC helped maintain abstinence and reduce craving. Brain scans revealed that NAC could help restructure the circuitry in the brain’s reward pathways after just 4 days [R].
NAC reduced the number of cigarettes smoked in 35 people after 3 months. Almost half of the people who took NAC quit smoking, while only one-fifth of the placebo group did [R].
In another study, NAC slightly reduced nicotine withdrawal symptoms. Smokers also rated their first cigarette after NAC as less enjoyable [R].
8) Depression and Mood
In a review of studies including over 500 people, NAC could improve symptoms of depression and overall functioning after 3 – 6 months [R].
Additionally, it improved the mood of people with depression after 3 months [R].
In another study, NAC had to be used for at least 4 months to improve depression [R].
It may also balance mood by reducing oxidative stress in the brain. In a study of 76 depressed patients, those who took NAC had higher brain antioxidant levels [R].
9) Bipolar Disorder and Mania
NAC could improve chronic health issues, such as heart disease and hormonal imbalance, in people with Bipolar Disorder. It had an indirect effect, affecting overall health, antioxidant status, and inflammation [R].
In another study with 17 bipolar patients, NAC improved low mood and overall symptoms after 6 months [R].
Larger studies are currently underway to confirm the benefits of NAC for Bipolar Disorder [R].
NAC could also improve mania symptoms in a small study of 15 people after 6 months. The NAC group experienced less severe mania, while the placebo group experienced mood worsening [R].
10) Obsessive Compulsive Disorder (OCD)
NAC may help with OCD by balancing glutamate and increasing antioxidants in the brain. In a study of 44 OCD patients, NAC as an add-on to standard medications improved symptoms even in severe OCD [R].
In a study of 48 OCD patients who previously didn’t respond to drugs, NAC could safely improve symptoms after 3 months [R].
Some studies, however, didn’t find benefits to NAC for OCD [R].
Although the evidence is mixed, NAC may be useful for obsessive-compulsive disorders, according to a large review. Overall, it shows promising benefits and has very few side-effects [R].
11) Polycystic Ovary Syndrome (PCOS)
Clomiphene citrate is considered the gold standard for helping women with PCOS achieve ovulation. But more than half of women don’t respond to it. NAC is being researched as a potential alternative, although the studies so far have mixed results [R].
In the largest study of NAC in 150 women with PCOS who previously didn’t respond to treatments, NAC added to clomiphene citrate improved the ovulation and pregnancy rates after just 5 days. This was confirmed in another study of over 100 women [R, R].
In another study of 60 women with PCOS, NAC improved the quality of egg cells. It also increased embryo health during in vitro fertilization [R].
Women with PCOS often suffer from weight gain. NAC could improve metabolic symptoms in 46 women with PCOS, helping to reduce blood lipids, fasting glucose and insulin better than metformin (an anti-diabetic drug) [R].
NAC had similar benefits to metformin in a study of 100 women with PCOS. It reduced high testosterone, high insulin, irregular menstruation, and BMI after 6 months. Unlike metformin, NAC also lowered total and LDL cholesterol. NAC improved insulin sensitivity in another study of 31 women with PCOS over 5 – 6 weeks [R, R].
NAC alone did not help women with hard-to-treat PCOS in other studies. It possibly works better when combined with the standard drugs than when used as a stand-alone [R].
12) Male Fertility
Aside from potentially helping women with PCOS, antioxidant therapies like NAC may help increase fertility in men [R].
Oxidative stress can damage the sperm’s DNA, which reduces fertility [R].
In 120 infertile men, NAC improved semen quality and antioxidant status after 3 months [R].
Some studies looked at the fertility benefits of NAC with other antioxidants, such as B vitamins, vitamin C and D. This combination improved the sperm count in those with low sperm count in a study of 42 men [R].
Some men are “subfertile”–they’re less fertile but without an obvious underlying cause. In 84 such men trying to conceive with their partners, a NAC supplement combination (called Condensyl, with vitamins, zinc, fig extract, and vitamin E) increased pregnancy rates. It increased the “fertility potential” of these men, making a successful pregnancy more likely [R].
The typical NAC dose for improving fertility in these studies was 600 mg/day. Multi-compound antioxidant supplements can contain less NAC.
13) Sleep Apnea
NAC improved sleep, reduced apnea and snoring in one study of 20 people with Obstructive Sleep Apnea after a month. Long-term, it may reduce the need for continuous positive airway pressure therapy [R].
14) Skin Health
NAC-containing creams or gels may improve skin health. NAC can boost glutathione in the skin, protecting it from damage. It can also reduce skin inflammation and normalize skin cell division. It has been used for eczema, skin irritation, radiation-induced skin damage, wound healing, and acne.
In one study of 100 people, a 5% NAC gel helped reduce mild to moderate acne [R].
Case reports and animal studies support a range of skin benefits of NAC. Overall, NAC skin formulations are promising and very safe, although larger studies are harder to come across [R].
15) Chemotherapy Side Effects
NAC could prevent from chemotherapy or x-ray scanner side effects due to its antioxidant action. It can be safely used as an infusion, injection, or orally.
Cisplatin is a common chemotherapy that can damage the ears and kidneys. NAC ear injections prevented cisplatin damage and protected the ears in a study of 84 people [R].
NAC infusions could also reduce mouth ulcers and inflammation from chemotherapy in a study of 80 people with leukemia [R].
In a pilot study, oral NAC protected from the side effects of chemotherapy on the brain in 14 people with colon cancer [R].
NAC and other antioxidants may prevent from x-ray radiation used to diagnose bone cancers. Combined with vitamin C, ipoic acid, and beta-carotene, NAC protected 5 people from x-ray scanner damage in one study [R].
One study determined that even high very intravenous doses of NAC were safe in 28 people with kidney damage caused by chemotherapy [R].
16) Protecting the Ears
Interestingly, NAC may even protect the ears from hearing loss caused by loud music or sound damage.
It also protected 48 textile-industry workers from hearing loss after 2 weeks [R].
But in one unusual study, NAC taken before listening to loud live music in a nightclub for 2 hours had no protective effect in 31 people [R].
NAC may also help with ear inflammation. In 90 children with middle ear inflammation, NAC alone or combined with antibiotics improved symptoms. It had a stronger effect combined with the antibiotic [R].
NAC seems to have some benefits for children with autism, but these are still uncertain.
NAC alone reduced irritability in a study of 33 children with autism after 3 months [R].
But NAC had no benefits in children with autism in a different study [R].
In another, it could boost glutathione in 31 children with autism, but had no effect on their social functioning [R].
18) Dry Eyes
A 5% NAC cream worked as well as the typical steroid cream in a study of 20 people with dry eye syndrome. It improved burning, itching, and blurry vision after a month. It was also much more effective than artificial tears in another study of 20 people with dry eye syndrome [R, R].
19) Muscle Fatigue
The effects of NAC on exercise are not that straightforward. Overall, NAC tends to help muscles recover shortly after exercise and improves blood flow during intense exercise. It also seems to help elderly people improve their fitness and enhances endurance in athletes short-term.
However, long-term NAC with exercise may prevent proper muscle recovery.
In one study NAC supplementation improved demanding cycling performance in 10 athletes after 9 days. It increased their antioxidant capacity, physical performance, and muscle recovery [R].
But in one study of 80 men, NAC taken before exercise didn’t increase endurance or muscle blood flow [R].
One study concluded that NAC can alter the energy balance in muscles and hinder muscle repair. When given to 10 men after intense exercise, it lowered inflammation in the muscles but at the same time slowed down muscle recovery after 8 days [R].
And in another, NAC worsened performance and decreased power output during HIIT training in 9 athletes [R].
In a study of 12 men, NAC improved exercise performance after 6 days during which they trained every other day. Overall, NAC may help in situations that demand continuous intense exercise only over a short period of time [R].
Muscle Fatigue and Inflammation
NAC could reduce muscle fatigue in exercises that demanded only 80% muscle power, while it wasn’t beneficial for high-power training (higher muscle work rates) in 7 men [R].
Inactive or Elderly People
NAC taken for a week before exercising could speed up muscle repair and increase blood flow to the muscles in a study of 29 sedentary men [R].
20) Antibiotic Side Effects
Antibiotic side effects can arise from free radicals damage. As a strong antioxidant, NAC reduced side effects, prevented kidney and ear damage from several strong antibiotics in 2 studies of 100 people [R, R].
NAC could also protect the liver from the harmful effects of anti-tuberculosis drugs in a study of 60 people. Those who took NAC had intact livers after treatment, while 40% of those who didn’t take NAC suffered liver damage [R].
21) Red Blood Cells and Bleeding
In 61 people with thalassemia, an “antioxidant cocktail”, containing NAC with curcuminoids or vitamin E, improved anemia and hemoglobin levels after 4 months. NAC had similar benefits in 75 children with thalassemia, while also reducing DNA damage [R].
It also improved blood markers and antioxidant levels in 11 people with sickle cell anemia [R].
Additionally, NAC reduced the severity and frequency of bleeding in 43 people with a bleeding genetic disorder. This benefit was also linked to its antioxidant power [R].
1) Pain and Inflammation
NAC could alleviate complex pain in a study of 146 people over 2 years (DB-RCT), especially in those with poor circulation. The participants took 1,200 mg NAC daily [R].
NAC (1,200 mg/day) reduced inflammatory markers such as CRP and IL-6 in a study of 24 people with kidney disease. Given to 15 patients with severe burns, NAC reduced oxidative damage, increased antioxidant protection, and reduced inflammatory markers [R, R].
2) Insulin Resistance and Type 2 Diabetes
NAC can target insulin resistance thanks to its capacity to restore antioxidant levels and reduce oxidative stress. Plus, people with type 2 diabetes may have lower glutathione levels that NAC can replenish [R].
In one study, 14 people with type 2 diabetes took 1,200 mg of NAC every day for a week and had their blood drawn shortly after. NAC increases glutathione in platelets and normalized their activity, which could protect from heart disease in type 2 diabetes [R].
When glutathione is added to white blood cells of people with type 2 diabetes, it restores their immune and bacteria-fighting function. Since NAC increases glutathione throughout the body, it may be helpful for restoring antioxidant balance in people with diabetes [R].
When given to 128 people before a high-fat meal, NAC could help maintain antioxidants and blood vessel health. It reversed oxidative stress, which was very noticeable in people with type 2 diabetes and insulin resistance. Since the group was medication-naive, NAC may delay or prevent the need for anti-diabetes drugs in type 2 diabetes [R].
NAC does not affect type 1 diabetes, though, as factors aside from oxidative stress play a large role [R].
3) Alzheimer’s Disease
An antioxidant supplement containing NAC improved cognition and mood in 130 people with Alzheimer’s disease 2 studies [R]. Participants took the supplement for up to one year.
In one trial, NAC alone also improved all symptoms of Alzheimer’s Disease after 3 – 6 months [R].
4) Parkinson’s Disease
NAC may protect the brain in people with Parkinson’s Disease. In one study, people with Parkinson’s Disease took NAC for 3 months and then underwent brain scans. NCA improved the activity of their dopamine neurons, which are incredibly important in this disease [R].
New brain scanning techniques can now measure levels of the antioxidant glutathione in the brain, which could help guide and track treatment outcomes. NAC increased glutathione levels in the brain in 3 people with Parkinson’s Disease [R].
NAC may help improve symptoms of schizophrenia and psychosis by balancing the brain’s glutamate levels, fighting oxidative stress and inflammation.
NAC improved cognition and working memory in 58 people with psychosis, taken at a higher dose of 2 g/day. It also reduced symptoms like mania and hallucinations as well as improved response to standard treatment in another study of 121 people [R].
Combined with antipsychotics, NAC improved overall symptoms in 42 people with schizophrenia with no side effects. It especially helped with low mood and apathy [R].
This may be because NAC helps the brain waves become more synchronized. One EEG study in people with schizophrenia showed that this synchronous brain wave activity can predict improvements [R].
Overall, NAC may improve symptoms of schizophrenia, based on the available clinical trials [R].
Other clinical studies are currently underway that will soon tell us more [R].
NAC could also reverse the risk of schizophrenia in genetically predisposed mice by normalizing brain connections [R].
6) Heart Disease
Oxidative damage is one of the underlying causes of heart disease. NAC prevented heart damage in mice with diabetes [R].
It also reduced heart damage in rats with chronic heart failure, while also improving fatigue and exercise tolerance [R].
In almost 100 patients who had heart attacks, NAC sped up recovery short-term. Long-term, it could improve heart health and reduce complications [R].
Serious heart arrhythmias are also linked to oxidative stress. In blood taken from patients, those who took NAC aside from drugs used to treat arrhythmias had higher antioxidants and reduced inflammation [R].
7) Bone Health
In 21 women who recently went through menopause, NAC strengthened the bones and their density when added to a vitamin D and calcium supplement regimen. It was used safely for over 3 months [R].
8) Ulcers and H. Pylori
H.pylori is the most common cause of ulcers. NAC somewhat enhanced the effects of H.Pylori treatment in one study of under 100 people. In another of 60 people, it helped antibiotics penetrate to the site of infection [R, R].
NAC may play a role in overcoming antibiotic resistance by destroying biofilms. NAC increased the sensitivity of H.Pylori to antibiotics by disrupting biofilms in a study of 40 people. It could be given before antibiotics to boost their effect [R].
Oxidative stress plays a role in developing diseases like ALS. NAC offers some hope for ALS patients. But so far, it was only shown to prevent ALS-like degeneration of brain cells [R].
10) Gut Health and SIBO
As a powerful antioxidant, NAC can help protect the gut and reduce small intestinal bacterial overgrowth (SIBO).
Gastric reflux, or heartburn, is alarmingly common. In 90 people with gastric reflux (GERD), NAC improved most symptoms after 3 months given as an add-on to standard PPI drugs [R].
But these medications, PPIs, can often cause small bacterial overgrowth, as they reduce the gut’s pH making it more hospitable for bacteria. One study of 30 people confirmed this, as well as that several strains of antibiotics combined with NAC, can reverse the condition. Once reversed, NAC and probiotics restored the gut barrier and prevented SIBO in the long run [R].
NAC also reduced gut inflammation In 37 people with colitis, helping to reduce inflammatory substances like IL-8 [R].
In rats, it could also reduce leaky gut, helping to strengthen the intestinal barrier and boost antioxidant defense [R].
NAC has already been researched for improving cognitive function in Alzheimer’s, Parkinson’s, and schizophrenia. It is also currently being researched for boosting cognitive performance after general anesthesia [R].
12) Brain and Spine Injuries
NAC may act help recover from brain trauma or reduce the damage from various stressors in the brain by combating free radicals [R].
It could reduce the effects of traumatic brain injuries even during combat, according to a study of 81 U.S. soldiers [R].
NAC can cross the blood-brain barrier in children with traumatic brain injuries without side effects [R].
It could also increase antioxidants and helped protect the brains of children with a deadly, rare brain disease [R].
In pregnant women, NAC could protect their fetuses from the complications of vaginal infections on the brain [R].
13) Kidney Disease
Oxidative stress can cause kidney failure in the most severe cases. It was first shown that NAC can protect the kidneys from damage in rats [R].
Since then, at least 30 clinical studies have looked at the protective effects on NAC in kidney injury, before or after kidney or heart surgery, as well as when it comes to thyroid problems in kidney disease. Most of the studies have shown positive results, which brings NAC into hospitals as a potential treatment for severe cases of kidney and lung disease [R, R, R, R, R, R, R, R, R, R, R, R, R, R].
When used in serious diseases and to reduce organ damage, NAC is usually given as an infusion or injection.
14) Lupus and ADHD
People with lupus have dysfunctional T cells, an important component of the immune system. T cells can be rebalanced by targeting mTOR by increasing glutathione with NAC. In one trial, NAC improved lupus and blocked mTOR in 36 people at higher doses (2.4 – 4.8 g/day) after 3 months [R].
Lupus also increases the likelihood of suffering from ADHD. NAC reduced ADHD symptoms in patients with lupus in a study of almost 100 people. NAC improved cognition, impulsivity, and overall symptoms given at up to almost 5 grams/day [R].
NAC could also protect animals from radiation, protecting the DNA by its antioxidant capacity [R].
No clinical studies proved any cancer-fighting benefits yet.
Only in one study of 25 women who had cancer and were in remission, NAC could help rebalance female hormone levels [R].
People with HIV tend to have lower antioxidant and glutathione levels. In one study, 1 g of NAC per day was enough to bring glutathione levels up in 12 people with HIV after only a week. In another 6-month study, those who took 600 mg NAC/day also reduced the HIV virus number and activity while boosting the immune response [R, R, R].
NAC could boost the activity of macrophages and glutathione levels in people with HIV and tuberculosis, which helps fight off the infections [R].
Higher glutathione levels from NAC could prevent the HIV virus from replicating in cells [R].
17) Gum Health
NAC improved gum bleeding in a study of 33 people with gum disease after surgery [R].
18) Mountain Sickness
NAC somewhat helped with mountain sickness in one study in 84 people living in very high altitudes in Peru (over 4,000m). It did not work better than the standard drug, acetazolamide, though [R].
19) Cystic Fibrosis
NAC reduced inflammation and increased antioxidants in 18 women with cystic fibrosis who were deficient in glutathione [R].
The short-term effects are not that evident, but long-term NAC use may be more beneficial [R].
20) NAC and Pregnancy
There is not enough research to claim whether NAC is safe in pregnancy, so we don’t advise that you take it if you are pregnant without consulting a doctor first.
Several studies show some benefits of NAC for pregnant women or their babies.
NAC helped reduce unexplained pregnancy loss in 80 women. A combination of NAC and folic acid was used [R].
NAC could protect the fetus from brain injury caused by the mother’s bacterial infection [R].
In 29 pregnant women low antioxidant status, NAC in combination with other antioxidants improved pregnancy outcomes [R].
It also helped prevent preterm births in 280 women with vaginal infections [R].
21) Compulsions in Children
NAC reduced obsessive skin picking in a study of 66 children with the disorder. Children took NAC for 3 months and tolerated it well [R].
It could also reduce compulsive nail biting in 42 children [R].
It seems to help only with obsessive or compulsive behaviors. But NAC did not improve tic symptoms in 31 children with Tourette Syndrome [R].
22) Emergency Medicine
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 [R].
Side Effects & Cautions
NAC seems to be a safe substance with very few known side effects.
Occasionally, oral supplements can cause nausea, vomiting, diarrhea, or constipation.
Because of the sulfur-containing cysteine, NAC does smell bad (sulfur smells like rotten eggs), which makes the powder form unappealing for most people.
People with severe liver damage can’t make GSH from cysteine and may need to take a bioavailable form of GSH itself [R].
Since NAC can impact the platelets and reduce coagulation[R], take precaution or consult your doctor if you:
- Have a bleeding disorder
- Are having surgery soon, because of an increased risk of bleeding during and after surgery
- Take blood-thinning medication, as in combination with NAC the effect may be stronger
800 – 2,400mg of NAC was very common across clinical studies. If you have a chronic health condition, you can consider taking a higher dose. The daily doses are usually divided into 2-3 times per day.
Some studies the benefits of NAC for reducing addiction and mental health issues used doses closer to 3,000 mg/day.
For general wellness or gut health, 600 mg a day is the typical dose.
A maximum safe dose of NAC has yet to be determined.
Can you get NAC from Food?
The simple answer is no.
NAC is not found in foods. However, you can get cysteine–the amino acid NAC releases–from various foods.
L-cysteine in Food
As an amino acid, cysteine is found in protein-rich foods. The other sulfur-containing amino acid is methionine, which also helps make glutathione. This means that only 2 of the 20 amino acids normally present in proteins contain sulfur. Overall, proteins contain between 3 and 6% of these 2 sulfur amino acids [R].
Food sources of cysteine (which also provide methionine) include [R]:
- Red meat and poultry (equal cysteine/methionine ratio)
- Eggs (higher in cysteine)
- Fish (higher in methionine)
- Dairy (higher in methionine)
- Grains and starch-rich foods (higher in cysteine than in methionine)
- Soybeans (lower in both amino acids than animal proteins)
Additionally, your body can make cysteine from other sulfur-containing compounds found in foods, such as [R]:
- Broccoli and other cruciferous vegetables
- Some mineral waters contain sulfate ions (such as San Pellegrino)
Importantly, your body uses sulfur for sulfation, an extremely important detox pathway, and to make other important compounds aside from cysteine (like SAM). But drugs like acetaminophen also need to go through this sulfation pathway to be eliminated, putting additional strain on the liver and increasing sulfur requirements [R].
This means that reducing your intake of acetaminophen-containing OTC painkillers like Tylenol can lower the strain on your liver, lower your dietary sulfur requirements, and allow your body to make better use of sulfur-compounds.