What Is N-acetylcysteine, and How It’s Used for Mental Health - GoodRx - GoodRx (2024)

Researchers developed N-acetylcysteine (NAC) in 1960 as a "mucolytic" to loosen thick mucus. The medication was later used for other purposes, including acetaminophen (Tylenol) overdoses. Now, researchers believe that NAC also affects chemical messengers within the brain. Because of this, NAC has been studied for its potential mental health benefits.

Read on to learn how NAC works and whether it is effective in treating mental health conditions.

What is N-acetylcysteine (NAC) and what is it used for?

NAC is FDA-approved for acetaminophen overdoses and as a mucolytic. In acetaminophen overdoses, NAC prevents or lessens liver damage. As a mucolytic, NAC breaks up mucus in people with lung diseases. These include bronchitis, asthma, or chronic obstructive pulmonary disease (COPD).

How does NAC work?

NAC is a form of the amino acid cysteine. Cysteine is naturally present in your body.

When you take NAC, your body turns it into an antioxidant called glutathione. Antioxidants are molecules that prevent damage to your body caused by “reactive oxygen species” (ROS). Although our bodies naturally produce ROS, high levels can be harmful.

NAC is often used when a person overdoses on acetaminophen. Taking too much acetaminophen causes high levels of N-acetyl-p-benzoquinone imine (NAPQI) in the body. NAPQI is a toxic product of acetaminophen metabolism that damages your liver. NAC counteracts NAPQI by providing your body with glutathione. Glutathione detoxifies (inactivates) NAPQI and prevents liver damage.

Can NAC treat mental health conditions?

Over the past decade, researchers have studied NAC for treating mental health conditions. Some of these include depression, bipolar disorder, schizophrenia, and obsessive compulsive disorder. In these studies, doses of NAC ranged from 1200 mg per day to 3600mg per day. Below, we’ll discuss how NAC works in the brain and what current research suggests about if it can treat mental health conditions.

How might NAC affect brain function?

NAC affects many different processes in the brain. Some of the ways that NAC may impact the brain include:

• Lowering stress. NAC provides antioxidant effects to fight ROS. When ROS levels are high, they can damage your body’s cells and tissues. ROS can cause oxidative stress, which can damage brain cells.

• Lowering inflammation. NAC lowers inflammatory chemicals, called cytokines, within the brain. Inflammation may play a role in conditions like depression and schizophrenia.

• Lowering glutamate levels. Glutamate is a chemical messenger in the body. High levels of glutamate are associated with different mental health conditions. Since NAC may lower glutamate levels, it may help treat certain mental health conditions.

  See Also

  N-ACETYL CYSTEINE (NAC): Overview, Uses, Side Effects, Precautions, Interactions, Dosing and ReviewsThe Definitive Guide to N-Acetyl Cysteine (NAC)Glutathione vs. NAC: An Expert Comparison of AntioxidantsThe Amazing Benefits of N-Acetyl Cysteine (NAC)

• Raising dopamine levels. Dopamine is another chemical messenger involved in controlling movements and emotional responses. It plays a key part in the brain’s “reward system.” Many mental health conditions are associated with unbalanced dopamine levels. Since NAC raises dopamine levels, it may help treat some mental health conditions.

NAC in depression and anxiety

Some researchers believe that NAC treats depression by lowering inflammation and glutamate levels. A large meta-analysis — a review of many studies — found that NAC helped treat depressive symptoms. But, another study showed that NAC didn’t improve depression symptoms. More studies are needed to determine if NAC is effective for treating depression.

People have also tried taking NAC to lower anxiety symptoms. There is currently not enough information to recommend NAC for treating anxiety.

NAC in bipolar disorder

NAC has also been studied as a medication to treat bipolar disorder.

Studies have looked at combining NAC with other bipolar disorder medications. One small randomized, controlled clinical trial (the gold standard for clinical studies) showed that NAC could help treat depression in people with bipolar disorder. Another randomized, controlled trial also found that adding NAC helped improve depressive symptoms.

But, a recent meta-analysis showed a different outcome. In this review, adding NAC to standard treatment for bipolar disorder didn't improve depressive symptoms. More studies are needed to see if NAC is effective at improving symptoms of bipolar disorder.

NAC in schizophrenia

NAC’s antioxidant effects may potentially be helpful in treating schizophrenia.

A meta-analysis of six studies found that schizophrenia symptoms improved when NAC was taken alongside other schizophrenia medications. And, in people with psychosis — where the mind can’t recognize reality — it’s possible that NAC’s effects on glutamate levels can improve memory. Other studies have also shown improvement in attention, processing speed, and memory.

NAC in obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a long-lasting mental health condition. One small study found that NAC didn’t reduce OCD severity. But, it did have potential benefits of reducing anxiety in certain people with OCD. Another small study looked at adding NAC to fluvoxamine. Fluvoxamine is an antidepressant medication that treats OCD. The study showed that NAC helped treat OCD symptoms when added to fluvoxamine.

More studies are needed to see if NAC is effective at improving symptoms of OCD.

Can NAC be used in substance use disorder?

Substance use disorders may be associated with imbalances in glutamate and dopamine. Specifically, glutamate and dopamine may work together to reinforce addictive behavior. And remember: NAC may lower glutamate and raise dopamine levels in the body.

Different studies have looked at whether NAC can promote abstinence from various substances. NAC may be beneficial in reducing cravings specifically. Below, we’ll discuss a few studies that looked at how effective NAC is at treating addiction.

NAC in tobacco use disorder

Quitting smoking (smoking cessation) reduces your risk for many illnesses. This includes cancer, lung disease, and heart disease. But quitting smoking can be very challenging because nicotine is addictive.

Researchers have studied whether NAC is effective for treating tobacco use disorder. A small trial showed that people taking NAC smoked fewer cigarettes daily than those who did not take NAC.

Some researchers believe that NAC helps reduce cravings. In one study, heavy smokers were given a cigarette after they were asked to stop smoking for about 3 days. People taking NAC found the cigarette less rewarding than people not taking NAC. But more research is needed to see how helpful NAC is for treating nicotine use disorder.

Importantly, there are FDA-approved medications available for smoking cessation. Talk to your healthcare provider to find the best treatment to help you quit smoking.

NAC in cannabis use disorder

Cannabis use disorder (CUD) is tricky to treat, especially in adolescents. Even in adults, there are no tried and true medications that treat CUD.

But one trial looked at over 100 teenagers using cannabis. The study found that NAC may be helpful in stopping cannabis. In this study, NAC didn’t have many side effects and was well-tolerated.

The same researchers then wanted to find out whether NAC could treat CUD in adults. They studied over 300 adults who took either NAC or placebo (a pill with nothing in it). NAC wasn’t shown to be more effective than placebo.

Another study looked at whether NAC could treat depression in adults with CUD. Depression can be common among people with CUD. But this study of over 300 adults also didn’t show that NAC improved depression symptoms.

Overall, it’s not clear whether NAC is effective at helping people reduce cannabis use. Larger studies are needed to see whether NAC is beneficial in CUD.

NAC in cocaine use disorder

NAC has also been studied for reducing cocaine cravings. NAC may help correct glutamate imbalances caused by long-term cocaine use. A large review of 21 studies suggests that NAC may prevent relapses in cocaine use disorder. But, it’s important to note that only 6 of these studies were of people and the other 15 were of animals.

The benefits of using NAC for cocaine use disorder is not clear. More research is needed to determine if NAC can help people lower cocaine use.

How safe is NAC for mental health conditions and substance use disorders?

It’s unclear how effective NAC is at treating mental health conditions and substance use disorders. But, it’s good to know that NAC appears to be well-tolerated. In studies, most side effects experienced after taking NAC were gastrointestinal, such as an upset stomach.

NAC is not FDA-approved for any mental health conditions or substance use disorders. It’s important to talk with your healthcare provider if you’re considering using NAC.

If you or someone you know struggles with mental health conditions or substance use, help is available. Call SAMHSA’s National Helpline at 1-800-662-HELP (4357) to learn about resources in your area.

Does NAC interact with my other medications?

Like many dietary supplements, NAC can interact with other medications you take. For example, NAC can raise nitroglycerin’s effects. In one study, this led to bad headaches. Talk to your healthcare provider before taking NAC.