Which NAC supplements are best?

Taking NAC, or N-acetyl cysteine, as a supplement is growing in popularity. The supplement form of the amino acid cysteine, NAC is not found in food and not naturally produced by the body — but it’s still useful. It’s one of the few supplements proven to help mitigate kidney and liver damage. It can also be found in prescription drug format, but its supplement format is popular for home use. 

A top NAC supplement is the Thorne NAC Capsules, a super high quality 500 milligram NAC supplement from a trusted brand that’s odorless and doesn’t oxidize quickly.

What to know before you buy NAC supplements


NAC is a highly potent amino acid with a number of uses. It increases glutathione levels, assisting with liver detoxification; supports respiratory health; and can protect the kidney. It’s often used in conjunction with acetaminophen or other drugs that can damage the liver and is often prescribed by doctors for these uses. 

As an amino acid supplement, it also has a large number of uses, from treating serious health conditions and addictions to being a post-workout supplement and general health protectant. As with many similar supplements, not all of its potential benefits are well researched or verified. It’s always best to be skeptical of outlandish health claims. If a supplement sounds too good to be true, it probably is.


Because regulation of supplements is minimal, the brand you purchase from can mean a great deal more than it does for prescription drugs. Look for a highly reviewed brand with a verifiable history and source. Ingredients should be clearly labeled on the packaging, and it should be easy to verify if the product includes common allergens. NAC is a popular supplement, so many brands have a version. Look for one you know and trust when purchasing. 

What to look for in a quality NAC supplement


  • Capsule: Most NAC supplements come in capsule form. These are cheap to produce and easy to swallow due to their smooth texture. Most capsules are made of gelatin, though vegetable cellulose options are becoming more popular. Capsules often contain a lower supplement dose than tablets.
  • Tablet: Tablets are pressed into shape, rather than being contained. They’re cheap to produce, too, but they’re less popular as they can be difficult to swallow due to their shape and texture. They also often have a taste, because they’re not encased in a neutral material. 


Most NAC supplements offer a 500- or 600-milligram concentration. NAC is generally safe for adults to take up to 2,000 milligram of per day, though this is an unusually high dosage. Talk to a medical professional about the correct dosage. 


Most supplements contain some additives for texture and taste, to prevent odor, or as preservatives. Look carefully at the additives used, their source, and how they might affect you, especially if you have health issues that might be exacerbated by unknown ingredients.  

How much you can expect to spend on NAC supplements

Most NAC supplements cost between 10-30 cents per pill, depending on concentration, derivation and brand. As supplements go, these are affordable. 

NAC supplement FAQ

Do NAC supplements help prevent or treat COVID-19?

A. NAC supplements are occasionally used to help treat lung conditions, and there are some studies backing up NAC’s use to treat COPD and chronic bronchitis. But there is little to no medical evidence as to its efficacy in treating COVID-19. There are no miracle cures for COVID-19, including dietary supplements. 

Are NAC supplements safe?

A. Generally speaking, though as with all medical treatments and dietary supplements it’s best to check with a medical professional before use. Many recommend that those who use NAC drink extra water while taking it. It can interact with some medications, and can cause some mild side effects such as an upset stomach or fatigue. Stop use of any supplements if serious side effects occur.

What’s the best NAC supplement to buy?

Top NAC supplement

Thorne NAC Capsules

Thorne NAC Capsules

What you need to know: This is a 500-milligram NAC capsule with great reviews from a brand trusted for purity and effectiveness. 

What you’ll love: Reviewers loved that it had no smell, as many capsules do. It doesn’t contain common allergens or gelatin, making it vegan friendly. 

What you should consider: It’s on the more expensive end of a generally affordable supplement. Thorne products in general are usually very expensive.

Where to buy: Sold by iHerb

Top NAC supplement for the money

NOW 600mg NAC Capsules

Now 600 Milligram NAC Capsules

What you need to know: These 600-milligram capsules come in bottles of either 100 or 250 capsules. 

What you’ll love: They’re highly affordable, vegan and free of common allergens. Reviewers raved about the value for the price. 

What you should consider: Some found that the capsules oxidized quickly, and complained of dark spots in the capsules. 

Where to buy: Sold by iHerb

Worth checking out

Life Extension 600mg NAC Capsules

Life Extension 600 Milligram NAC Capsules

What you need to know: This is a small bottle of high-quality 600-milligram NAC capsules. 

What you’ll love: They’re free of many additives and vegan. They’re also relatively affordable. 

What you should consider: They only come in bottles of 60 pills, meaning they’re a bit more of a pain to purchase in bulk. 

Where to buy: Sold by iHerb


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Arabella Matthews writes for BestReviews. BestReviews has helped millions of consumers simplify their purchasing decisions, saving them time and money.

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