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NAC For Anxiety And OCD: Does It Work? What’s The Best Brand?

N-acetylcysteine (NAC) is a prodrug of L-cysteine which is a precursor to glutathioneーthe main antioxidant produced by the body. Antioxidants are molecules that prevent the oxidation of compounds, a process that results in damage to the body.

Some psychiatric disorders occur due to the dysfunctional metabolism of another glutathione precursor, glutamate. Studies have therefore found that glutathione depletion is implicated in some mental disorders, particularly anxiety and anxiety-related disorders such as Obsessive-Compulsive Disorder (OCD).

Since the body breaks down glutathione rapidly, it is recommended to instead take NAC in order to enhance natural glutathione production.


One study demonstrated that when scientists induced OCD-related behavior in mice using serotonin receptor agonists, supplementing with NAC blocked behavioral symptoms following 3 weeks of administration.

Several studies in humans have found that NAC effectively reduces symptoms of OCD and anxiety. However, these same studies often concluded that NAC’s ability to reduce OCD severity is not considerable and that future studies with larger cohorts will be required before we can be sure of NAC’s potential.

NAC Dosage For OCD

The dosage of NAC used in studies for the treatment of OCD typically ranges from 2400 to 3000 mg a day, though a few case studies only used 1800 mg daily and still resulted in an improvement in negative disorder-related habits.

NAC is usually divided into 2-3 daily doses, though it’s not clear how vital this is.    

How Long Does It Take For NAC To Work For OCD

Most studies administer NAC over the course of 12-weeks, however some went for as long as 16 weeks. Although improvements have been seen in as little as 2 weeks, some individuals may need to use 3000 mg of NAC daily for at least 4 weeks to experience significant results.

NAC For Anxiety

In zebrafish, NAC not only reduced anxiety but also reversed oxidative damage caused by chronic anxiety. In human studies, researchers found that NAC improves anxiety-related symptoms, such as nail-biting and skin-picking

Anxiety often accompanies manic depressive disorder (MDD)ーa disorder also resulting from impaired glutamine metabolism. Interestingly, studies involving long-term treatment with NAC have shown a reduction in depression-associated anxiety. However, this was not due to its effect on glutamine, rather its ability to restore a healthy neural feedback loop which is often altered in patients affected by MDD.

NAC Dosage For Anxiety

Similar to OCD, it is also recommended to take 2400 to 3000 mg daily split into 2-3 doses for treating anxiety.

How Long Does It Take For NAC To Work For Anxiety

While most studies have a duration of 12-16 weeks, improvements are typically seen within 2-4 weeks of use. 

NAC Supplement Reviews

NAC was recently banned by Amazon yet we believe it’s completely safe and effective to use. However, it’s important to keep in mind that NAC interacts with nitrate-based drugs, such as the vasodilator nitroglycerin so you should make sure to consult with your doctor if you’re unsure of potential drug interactions.

NOW   NAC 600 mg - 250 Vegetarian Capsules

Best NAC Supplement

NOW   NAC 600 mg – 250 Vegetarian Capsules

Each bottle of NOW NAC contains 250 vegetarian capsules with each capsule providing 600 mg of NAC. It is recommended to take 1 capsule twice daily, however, for best results you should consider taking 2 capsules anywhere from 2-3 times daily. Each capsule also contains 25 mcg of selenium and 50 mcg of molybdenum to promote healthy enzyme function.

This NAC supplement has an impressive 5-star average. One reviewer reported that their severe ADHD-related skin-picking habit has almost ceased completely and that their anxiety leveled out following 3 weeks of use.

Pure Encapsulations NAC (N-Acetyl-l-Cysteine) 900 mg - 120 Capsules

Most Potent NAC Capsules

Pure Encapsulations NAC (N-Acetyl-l-Cysteine) 900 mg – 120 Capsules

Pure Encapsulations NAC contains 120 hypoallergenic capsules per bottle. Each capsule contains 900mg of NAC and it is recommended to take 1-2 capsules per day, between meals. However, we believe that it’s best to take up to 3 capsules per day for best results.

Pure Encapsulations NAC is more expensive than its competitors and only provides a 40 days supply. So, if you’re on a tight budget, this supplement may not be your best bet.

Thorne   NAC (N-Acetylcysteine) - 90 Capsules

Best NAC Capsules For New Users

Thorne NAC (N-Acetylcysteine) – 90 Capsules

Thorne’s NAC supplement contains 90 capsules per bottle and each capsule provides a serving of 500 mg of NAC. The company recommends taking 1 capsule 2-3 times daily, but again, we suggest a higher dosage of 5-6 capsules spread throughout the day for significant results.

Based on our serving recommendation, each bottle will only last 18 days, so this product may not be the best value. However, the product is only $25 so NAC by Thorne could be a good place to start when first trying out NAC.

Integrative Therapeutics   NAC - 60 Capsules

Best NAC Gelatin Capsules

Integrative Therapeutics NAC – 60 Capsules

NAC by Integrative Therapeutics contains 60 capsules, each providing 600mg NAC per serving. Each bottle only provides 10 servings, based on our recommendation for optimal dosage, so it might be best to buy three bottles at once in order to experience significant results. We suggest taking 4-5 capsules throughout the day.

One thing we want to mention about this product is that its capsules are non-vegetarian, so you may want to use another product if you prefer to avoid gelatin.

Source Naturals  N-Acetyl Cysteine 600 mg - 120 Tablets

Best NAC Tablets

Source Naturals N-Acetyl Cysteine 600 mg – 120 Tablets

Source Naturals NAC is the most potent supplement in this review, providing 1000mg of NAC in each capsule. You only need to take up to 3 capsules per day to reach the effective dosage for treating anxiety- and OCD-related symptoms. We recommend taking 1 capsule alongside each meal.

At just $22 per bottle for 120 capsules, this is by far the most cost-effective supplement. If you’re against GMO, this product is perfect for you as Source Naturals NAC is non-GMO validated.

Editor’s note: we are regularly updating this review. If you see any problems, weird interpretations of the data, or just want to say hi, please reach out to hello@the-unwinder.com.

Photo by Denys Nevozhai on Unsplash

About the author

Lucy is a UK-based freelance writer focusing on biological content, whether it may involve animal biology or health and well being. Having achieved a First Class Zoology degree at the University of Bristol, Lucy has a diverse knowledge base and enjoys writing for others. Lucy is also a medical student in London who enjoys, in her free time, weight lifting at the gym or hiking along precarious routes in the great outdoors.

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