Last Updated on February 16, 2024 by Lindsay Delk, RDN

If you or someone you love suffers from obsessive-compulsive disorder (OCD), you may explore additional options for treatment. Traditional treatments usually involve medication and cognitive behavioral therapy. But my family member’s psychiatrist introduced me to another player in the field: N-acetylcysteine (NAC). Let’s break down the research and potential benefits of NAC for OCD and OCD-related disorders, such as trichotillomania (hair pulling), nail biting, and skin picking, when added to traditional treatments.

This post was written by Lindsay Delk, RDN. It is for informational purposes and is not intended to replace medical advice or instructions given by your healthcare provider. 

This post contains affiliate links. If you purchase through these links, I will earn a small commission at no extra cost to you.

"NAC N-Acetylcysteine" in white letters on a blurry light blue background

What is NAC?

NAC is short for N-acetylcysteine. It is the supplement form of the amino acid, cysteine. NAC is a nutriceutical with antioxidant and anti-inflammatory properties. It is commonly used to treat acetaminophen (Tylenol) overdose, and it may also be beneficial for other health conditions, such as liver disease and respiratory infections.

NAC Health Benefits

  1. Antioxidant Support: NAC aids in the production of glutathione, a strong antioxidant that protects the body from free radicals. Free radicals can cause cell damage and contribute to chronic diseases, such as cancer and heart disease.
  2. Liver Protection: NAC has long been used to prevent liver damage in patients who took an overdose of acetominophen. It can help protect the liver from damage caused by toxins.
  3. Respiratory Function: NAC may improve respiratory health by thinning mucus in the airways. It is often used as a treatment for chronic bronchitis, asthma, and other respiratory conditions.
  4. Mental Health Support: There is increasing evidence that NAC could have potential benefits in managing some mental health disorders.
"OCD Obsessive Compulsive Disorder" written on a notebook and surrounded by a cactus, pen, and leaves


NAC is a precursor to the amino acid cysteine. Amino acids are the building blocks of proteins, and they play a crucial role in many biological processes. Cysteine is a semi-essential amino acid. Your body can produce it on its own, but there are situations where the body’s production may not be enough. So consuming it becomes necessary.

Cysteine has 2 key roles in your body:

  1. It helps your body produce glutathione, a major antioxidant that guards your cells against damage from free radicals and oxidative stress.
  2. It helps regulate the glutamatergic system, which is related to reward-seeking repetitive behaviors.

Because of these 2 key roles, NAC may help people with OCD in 2 main ways:

  • Working as an Antioxidant and Anti-Inflammatory

Oxidative stress and chronic inflammation happen when there are too many free radicals causing damage in your body. Chronic inflammation has been linked to various mental health disorders, including OCD.

Antioxidants, such as glutathione, neutralize the harmful free radicals and reduce oxidative stress and inflammation. So by boosting glutathione production, NAC may help lower inflammation and some of the symptoms of OCD.

  • Regulating Glutamate

Glutamate is an essential neurotransmitter, but too much glutamate has been linked to a variety of psychiatric disorders, including OCD.

NAC works by helping to regulate glutamate levels in the brain. By helping to regulate glutamate, NAC could potentially ease the compulsive and obsessive behaviors of OCD.

Up close picture of a hand holding 2 white pills of NAC for OCD

Best NAC Supplement for OCD

Members of my family take NOW NAC 1,000 mg tablets, but you may want to begin with NOW NAC 600 mg and increase the dose as needed. Read my article about the best dosage of NAC here. I recommend and use NOW supplements because they have an excellent reputation for stringent quality control measures and are affordable.

It’s important to note that while NAC can be a useful adjunct treatment, it should not replace your medication or therapy unless directed by your healthcare professional. And don’t forget about the pillars of a good mental health diet here.

FAQ about NAC for OCD

Are NAC supplements safe?

NAC supplements are generally safe. The most frequent side effects are GI discomfort, but those are not common. Start with a low dose and increase the dose gradually. Don’t take NAC supplements if you are pregnant or breastfeeding, have asthma or a bleeding disorder, or take nitroglycerin. And always check with your doctor before starting any supplement.

Should I take NAC with or without food? Can I take NAC on an empty stomach?

It’s best to take NAC without food on an empty stomach. If you experience stomach discomfort when taking NAC on an empty stomach, try taking it with a meal or snack. It’s always a good idea to follow the instructions given by your healthcare provider or on the supplement package.

When is the best time to take NAC – morning or night?

You can take NAC any time of day. Because it’s best to take NAC on an empty stomach, you may want to take it in the morning before you eat or at bedtime if you haven’t eaten for about 2 hours.

How long does it take for NAC to work?

The effects and benefits of NAC may not be immediately noticeable. Research suggests that noticeable improvements may start to appear after about 12 weeks of consistent use.

Scrabble tiles spelling OCD on a light blue background

Other OCD Posts

NAC Dosage for OCD

Ashwagandha: An Ayurvedic Treatment for OCD, Anxiety, & Stress

Holy Basil for Anxiety

Anxiety Nootropics, Foods, and Drinks

Anti-Inflammatory Food List PDF (Free Printable)

Bottom Line

While NAC for OCD shows a lot of potential, you should never stop your medication or therapy without guidance from your doctor. NAC may be another tool in your OCD toolbox, but it probably will not be the only tool!

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