N-Acetyl L-Cysteine: Benefits, Side Effects & Dosage

What is N-Acetyl L-Cysteine?

The medical community more readily refers to N-acetyl L-cysteine (NAC) as acetylcysteine because NAC comes from the amino acid L-cysteine. NAC is also a biological sulfur-containing compound made in living organisms.

It helps promote a chemical known as glutathione, which cells, especially liver cells, used to detoxify the body. Glutathione makes the toxins water soluble, so they flush out the body easily. N-acetyl L-cysteine is also a potent antioxidant (x).

NAC’s popularity grew leaps and bounds during the peak of the COVID-19 pandemic as a natural and effective means that may help you avoid and treat the health concern. Before the pandemic, naturopathic and alternative medical doctors often prescribed NAC to help those with respiratory problems like Chronic Obstructive Pulmonary Disease (COPD) and other acute and chronic problems (x).

NAC Banned?

Likewise, Amazon banned NAC from their marketplace website based on the U.S. Food and Drug Administration official requested the removal of the supplement from the Over-the-Counter market. However, the FDA request proved inconclusive, and people continued to take the supplement (x).

Since that time, Amazon now sells NAC on its marketplace website. The ban had little effect on the supplement’s market thanks to 57 years of verifiable positive feedback. Even though Amazon banned NAC for a short time, consumers could still get the supplement at their local health food store.

Semi-Essential Amino Acid

NAC falls under the semi-essential amino acids. Your body produces these other amino acids, specifically methionine and serine. For example, if your body’s consumption of amino acids becomes extremely low, then N-Acetyl L-cysteine converts into an essential need, fulfilling your body’s demand for these components. Thus, NAC is an extremely valuable supplement to the health of your body.

Foods Containing N-Acetyl L-cysteine

Naturally, you can find the NAC in food with high protein levels, such as sunflower seeds, eggs, yogurt, turkey, chicken, cheese, broccoli, onions, whole grain products and legumes (x).

What is in NAC?

N-acetyl L-cysteine is a form of the amino acid cysteine, hence the “C” in NAC. Your liver makes NAC by altering cysteine. Cysteine is in many foods but NAC is only available when taken as a supplement (x).

Taking NAC has many health benefits for both direct and therapeutic use. Medical professionals use it to treat patients who have overdosed on paracetamol, fever reducing synthetic drug. The supplement has proven valuable in reducing the mucus thickness of cystic fibrosis patients.

NAC comes in various forms — an oral supplement, a mist and an injection. N-acetyl L-cysteine also works well as a topical, such as in dental treatments, to reduce plaque or to treat dry eyes. These incidents touch the tip of the iceberg, as there are many valid uses for this highly regarded supplement.

Please discuss taking any new supplement like NAC with your physician.

Benefits of N-Acetyl L-Cysteine

Research shows that glutathione functions as an internal antioxidant and provides a broad role in many of your body’s defenses. When someone takes N-acetyl L-cysteine, their body shows an increase in glutathione levels.  Therefore, NAC offers many benefits when consumed as a supplement. Scientific research backs these benefits and is worth knowing as a natural solution for many ailments (x).

Antioxidant Production

Thanks to NAC increasing glutathione levels in your body when you orally take the supplement, some consider it one of the most important antioxidants that your body produces naturally. Glutathione helps to neutralize the free radicals that cause damage to various tissues and cells in the body. It helps boost your immune system and may even increase your lifespan. Any NAC or glutathione benefits you learn about stem from the fact that it’s a tried-and-true antioxidant.

Glutathione is so beneficial to our health that the Pharmacy Compound Advisory Committee (PCAC) voted to include compounded glutathione on the “able to compound” list. The decision resulted from personal experiences using glutathione successfully (x).

What is an Antioxidant?

On a biological level, antioxidants negate free radicals. Free radicals are destructive, uncharged molecules wandering unbalanced within the body. Free radicals are reactive, fierce, and short-lived toxic offshoots of oxygen metabolism.

Free radicals can develop severe health concerns and disrupt your routine body functions if unstopped. They activate “oxidative stress,” a harmful situation where free radicals wreak havoc faster than your body can overpower the wreckage. Here, antioxidants from NAC, thus increased glutathione levels, may help thus averting unhealthy conditions in your body.

So much research supports the advantages of antioxidants as biological weapons that they rescue your body from oxidative stress. Antioxidants contribute an electron to dismantle the disheveled chain reactions compelled by free radicals.

Antioxidant enzymes (polyphenols) also develop inside your body thanks to eating nutrient-rich fresh vegetables, fruits, and green tea. Today, it’s best to use NAC supplements that help your body raise its glutathione levels (x).

Liver and Kidneys Detoxification

N-acetyl L-cysteine plays a vital role in detoxifying the liver and kidneys. With chronic and low levels of toxic metals rising globally, studies show that NAC can help combat the adverse side effects of mercury, cadmium, lead, arsenic and other toxins (x). Extensive studies have proven the environment can adversely affect your health (x).

NAC can help treat other toxins in the body, like various pharmaceuticals. Those who have overdosed on medications such as Tylenol or paracetamol may benefit from NAC to limit liver and kidney damage (x).

Mental Balance

Glutamate is the most crucial neurotransmitter in the central nervous system and is essential to its healthy function. If the central nervous system has too much glutamate caused by not enough glutathione, the system may become damaged (x).

N-acetyl L-cysteine helps to ensure that glutamate levels remain sound by normalizing the levels. Properly regulating glutamate levels may help the body’s central nervous system lower stress levels and maintain mental balance.

NAC is effective in helping with your mental outlook thanks to its anti-inflammatory and antioxidant properties (x).

The recent findings from a vast amount of research showing that low serotonin levels cause a chemical imbalance in the brain are false. The chemical imbalance theory of depression led to a considerable rise in antidepressant prescriptions. Over-prescribing psychotropic drugs caused severe withdrawals when people tried to get off them (x).

Now that the truth is on the table, the need to find safe alternatives to mental health has become prevalent, like supplements like NAC, exercise, environmental toxins and stressful lifestyles (x).

It would help if you discussed taking any new supplement with your healthcare provider first.

Helps Improve Brain Function

The establishment that NAC helps the central nervous system also substantiates the supplement also helps boost brain health since glutamate is essential for the neurotransmitter to function and helps the brain stay healthy. It’s a positive connection to prevent Alzheimer’s disease and Parkinson’s disease.

Again, NAC prevents and reduces oxidative stress that can damage the brain cells, thus reversing the aging process (x). Patients who suffer from various memory issues or brain ailments may benefit from supplementing with NAC (x).

Helps With Fertility

N-acetyl L-cysteine is a potent antioxidant that can reduce DNA damage and protect the body against detrimental illnesses that develop from oxidative stress. One of the top causes of infertility is oxidative stress (x).

Many infertility issues in men can stem from insufficient antioxidant levels. Antioxidants are vital when it comes to reducing the effects of oxidative stress on the reproductive system. When the body is low in this essential amino acid, it can result in infertility (x).

Studies have demonstrated that supplementing with a steady dose of NAC and selenium positively affects fertility (x).

Women who experience polycystic ovary syndrome (PCOS) have fertility problems often. Supplementing with NAC helps encourage ovulation (x).

Supports Skin Health

As you age, your body creates fewer antioxidants that can help avert cell damage. Supplementing with NAC is a successful way to increase your body’s production of antioxidants. You can use NAC externally to reduce signs of aging, either topically or orally, because N-acetyl L-cysteine stimulates glutathione synthesis. As a result, it’s a helpful treatment for some skin diseases (x).

A study showed that NAC might help prevent complications and other side effects caused by acne. In fact, N-acetyl L-cysteine prevents the release and synthesis of inflammatory cytokines (x).

Specific inflammatory cytokines can injure the nerves and skin and play a role in causing pain. Thus, NAC supplements may help you avoid or reduce acne and pain (x).

Improves and Stabilizes Blood Sugar

Researchers have linked inflammation in body fat to obesity and high blood sugar levels. These health concerns left untreated can damage or destroy the insulin receptors in your body.

Impaired insulin receptors increase your chances of developing type 2 diabetes. However, natural methods have proven as favorable treatments for insulin resistance. NAC is among those natural approaches, including other antioxidants like vitamin E and alpha-lipid acid (x).

Initial studies have shown that N-acetyl L-cysteine helps reduce fat cell inflammation relating to metabolic disorders. NAC helps improve or stabilize insulin resistance and blood sugar levels (x).

Support Respiratory Health

N-acetyl L-cysteine can help with reducing several respiratory conditions. Reports indicate it benefits the lungs as an expectorant, which helps loosen thick mucus. The semi-essential amino acid also may help you if you have COVID-19 symptoms since the health concern relates to respiratory infections (x).

NAC even increases glutathione levels in the bronchial tubes and lungs, working to lessen inflammation and thin mucus. Studies have also shown that boosting glutathione levels may help relieve COPD symptoms and improve lung function (xx).

The supplement reduces coughing, wheezing, and varied respiratory attacks (x). Patients with asthma, bronchitis, pulmonary fibrosis and cystic fibrosis have found relief with NAC supplementation.

Immune Function

N-acetyl L-cysteine helps to increase the glutathione levels in your body. As a result, your body has an increase in antioxidants and anti-inflammatories. Studies show this can help boost the immune system, which benefits those who undergo cancer treatment or have seasonal influenza (x).

The medical field supports any application that helps increase patients’ immune systems when ill or undergoing harsh treatments. Therefore, using NAC may hinder virus replication in certain patients who are immuno-compromised, meaning they have a weakened immune system because of different treatments and conditions.

The supplementation may help to decrease the seasonal influenza severity, replication and duration of the illness, or side effects of cancer treatments. (x). Similar studies have shown that NAC may ease the DNA damage caused by cancer treatment and block certain cancer cell replication (xxx).

Helps With Epilepsy

A few studies have shown some benefits when epileptic patients take NAC with their standard medical care. Results show with acute and chronic treatment it delayed the seizures latency times based on rodent studies (x).

Research based on animal studies has also supported using antioxidants to treat epilepsy or neurological diseases. Since N-acetyl L-cysteine increases glutathione levels and thus antioxidant levels, it may help those who experience this neurological concern (x).

Where to Buy N-Acetyl L-Cysteine (NAC) Supplements?

You can purchase N-acetyl L-cysteine (NAC) at BulkSupplements.com. The company is an industry-leading manufacturer and distributor of pure dietary supplements. BulkSupplements.com is not just a consumer brand. It also supplies pure ingredients to other brands that distribute food and other supplement products. All products at BulkSupplements.com are manufactured and tested according to current and proper manufacturing practices.

Are you interested in trying N-acetyl L-cysteine (NAC) as a dietary supplement for its potential to support immunity function, respiratory health, boost fertility, stabilize blood sugar levels, skin health, mental health and nerve function? Contact BulkSupplements.com to place an order today.

N-Acetyl L-Cysteine Supplement Dosages

When taking N-acetyl L-cysteine (NAC) orally, the recommended dosage is 600 mg up to three times daily. Studies suggest the dosage is effective for angina — chest pressure or pain — when paired with a nitroglycerin patch. As a treatment for chronic bronchitis, studies show a recommended dosage of 200 mg, taken twice daily with a maximum limit of 1.5 grams (xx).

COPD treatment supplementation is 400 mg to 1,200mg daily, split into equal doses. Studies suggest identical amounts to treat high blood homocysteine levels attributed to blood clots and arterial damage.

Patients who supplement with NAC to treat epileptic symptoms should consume 4 to 6 grams daily under the supervision of a medical professional.

For those who want to reduce the effects of seasonal influenza or COVID-19 and prevent the possibility of a heart attack or stroke developing, the recommended daily dose is 600 mg twice daily.

Please discuss with our primary care physician the application of intravenous and inhaled dosages. Only professionally trained medical personnel should administer this treatment.

N-Acetyl L-Cysteine Side Effects

Most research considers N-acetyl L-cysteine safe to take as a supplement. But, like any new supplement, it’s best to check with a healthcare provider first, making sure it’s right for you.

Your body produces this antioxidant and continually absorbs and filters excess amounts through your liver.

Some say NAC has a strong odor, but in capsule form, it’s not noticeable, and people rarely comment on it. Some common side effects that are mild:

  • Fatigue
  • Acid reflux
  • Diarrhea
  • Nausea
  • Excessive gas
  • Vomiting
  • Constipation
  • Excess mucus

The above list is for you to review with your doctor before taking N-acetyl L-cysteine. Also, something to remember in case you have these adverse reactions and need a cause.

Unquestionably, NAC supplements are safe. However, doses higher than seven grams can be toxic. With that, it’s best to avoid taking similar cystine forms while taking N-acetyl L-cysteine. Avoid supplementing with D-cysteine, D-cystine and 5-methyl cysteine, which you can discuss with your doctor (x).

Although side effects rarely happen, here are some other NAC adverse reactions for your awareness:

Reduced Blood Clotting

N-acetyl L-cysteine can help those who undergo specific surgeries like the liver and kidney. However, NAC lowers your body’s ability to form blood clots quickly. Some medical professionals suggest not supplementing with NAC if patients suffer from various bleeding disorders.

When scheduled to have surgery, you might cease taking NAC at least two weeks before the operation (x).

Nervous System Shifting

If you take N-acetyl L-cysteine orally, the supplements may cause lightheadedness, weakness in the limbs, drowsiness, and vertigo.

In rare cases, such as administering NAC for acute acetaminophen overdose (too much Tylenol), people experience increased cranial pressure, resulting in rolling headaches (x).

G Gastrointestinal Pain Discomfort or Pain

Some reports say NAC supplements taken orally may cause dyspepsia, heartburn and rectal bleeding, such as excess gas, loss of appetite, feeling too full, nausea and bloating.

However, the positives out ways negatives in this incident. Studies show the protective effects of N-acetyl L-cysteine on intestinal health and its mechanism (x).


Patients with asthma should only take NAC supplements if a medical professional closely monitors them.

Inhaled supplement forms may reportedly cause bronchospasm, limiting your ability to breathe and causing lightheadedness or shortness of breath.

You may not find NAC inhaling form on the market and only locate it through your healthcare provider.

Physicians use the inhaling form to help loosen thick mucus. The World Health Organization listed it as the most essential medicines needed for the health system (x).

Allergic Reaction

Because allergic reactions occur when taking vitamins, you must check with your physician before starting any new supplement.

In rare cases, patients adding N-acetyl L-cysteine to their regime have experienced a sudden drop in blood pressure, extreme drowsiness, liver problems, headaches, rashes, and fever.

If inhaled, N-acetyl L-cysteine has caused mucus excretion from the nose, mouth swelling, and tightness in the chest. But these are infrequent occurrences.

Six percent of the world population may undergo allergic reactions to the intravenous use of L-cysteine, resulting in hives, swelling, and other soft tissue inflammation (x).

N-Acetyl L-Cysteine Precautions and Warnings

Healthcare providers prefer pregnant or nursing women to avoid taking NAC supplements unless it’s necessary.

However, no studies show the supplement’s effects on an unborn child. No studies show if the supplement passes through breast milk in harmful quantities to the baby.

NAC Interactions With Medication

N-acetyl L-cysteine improves the effectiveness of several medications.

For example, the NAC supplements increase the efficacy of immunosuppressants such as azathioprine, cyclophosphamide and prednisone. The supplements also strengthen the effects of isosorbide and nitroglycerin, which help treat chest pain.

The increased effects may cause a dangerous drop in blood pressure, though some studies prove otherwise (x). Still, it is another reason you must speak with your doctor before starting a NAC supplement regimen.

The Bottom Line

N-acetyl cysteine (NAC) is a powerful agency your body needs to help it perform optimally. For over 57 years, the World Health Organization has encouraged the administration of NAC as an essential medication.

As a supplement, it boosts the valuable compound known as glutathione, which creates high levels of antioxidants in your body. Antioxidants avert the harmful effects of free radicals that cause damage at the cellular level. The damage can break down the central nervous system and immune system functions. Free radicals can also cause noticeable signs of aging and even mood swings. It also helps prevent age-degenerative diseases like Alzheimer’s and Parkinson’s as a robust neuroprotectant that successfully helps treat addiction.

NAC also assists your body in getting get rid of harmful heavy metals and other toxins that cause a host of health concerns.

In fact, scientific studies have proven that NAC can help support the liver, which decreases the concentration of toxins in the body across the board.

The supplement can even promote healthy skin and minimize acne outbreaks when taken orally or applied topically.

Studies show the link between many fertility issues and lower levels of glutathione. Thus, taking NAC supplements helps promote higher glutathione levels to improve both egg and sperm health, resulting in fewer fertility complications.

Comparably, N-acetyl L-cysteine is inexpensive and easy to use. Most people can tolerate the supplement with hardly any side effects. When there are any side effects, they usually are mild.

These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease.

Author: BulkSupplements Staff