Initially Posted: 02/15/2019 | Last Updated: 09/12/2020
N-acetyl cysteine (NAC) supplements tested by

Alphabetical list of the NAC supplement brands compared in this review:


Solgar NAC




Doctor’s Best Best NAC Detox Regulators


Carlson NAC




Life Extension N-Acetyl-L-Cysteine




NutraBio NAC


Nutricost NAC


Seeking Health NAC


Vital Nutrients NAC

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NAC (N-acetyl cysteine) is a supplement which the body converts into glutathione, an important antioxidant. NAC is promoted for many uses. These include "liver support," "immune support," and reducing symptoms of the flu and flare-ups of chronic bronchitis and COPD. But is there good evidence for these uses, and for therapeutic uses for other conditions such as Sjogren's syndrome, renal failure, schizophrenia, compulsive behavior, and polycystic ovary disease? reviewed the clinical evidence for NAC. It also purchased and independently tested popular NAC supplements on the market, comparing their quality, dosage, and features, and cost.

Among the products that passed testing, the cost to obtain an equivalent dose (600 mg) of NAC ranged from just 4 cents to 63 cents -- meaning that you can save a lot by shopping wisely. Some products contain added ingredients, but it may not be worth paying more for these. We also found that the daily suggested dose ranged just 500 mg to 3,000 mg, so it's critical that you know how much you really need rather than rely on labels.

Based on its tests ConsumerLab selected Top Picks among NAC powders, capsules, and tablets based on quality, value, and other features.

You must be a member to get the full test results, along with ConsumerLab's recommendations. You'll get results for 11 NAC supplements -- eight selected by ConsumerLab and three others that passed the same testing through our voluntary Quality Certification Program.

In this comprehensive review, you'll discover:
  • Which NAC supplements passed or failed our tests
  • ConsumerLab's Top Picks for NAC — our selection of the best NAC powders, capsules and tablets based on quality, value, and special features
  • The evidence for or against NAC for different conditions
  • Why additional ingredients are sometimes added to NAC supplements and whether they matter
  • What "free form" NAC means and whether it's important to look for it on labels
  • Dosage of NAC for specific uses
  • Concerns, cautions, and potential side effects with NAC

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