11 Best NAC Supplements (2023) Reviewed and Compared

Never miss a glorious update - click here!

✓ Medically Reviewed and Fact-Checked by Dr. Jesse Ropat, PharmD, RPh, B.Sc.

N-acetyl cysteine, known as NAC, is, simply, one of the most underrated supplements out there. Today we are covering everything you need to know about N-acetyl cysteine and the best NAC supplements on the market.

What is NAC (N-acetyl cysteine)?

Before we get into what N-acetyl cysteine is, let’s talk about cysteine.

Cysteine is a non-essential amino acid that serves an important role in protein production. It’s found in foods with high protein contents, and it can be produced by the body from other amino acids.

NAC (N-acetyl cysteine) is the supplement form of cysteine.

N-acetyl cysteine helps the body develop antioxidants and provides a wide variety of other health benefits, even ranging into psychiatric and mental health benefits.

Okay, but what do antioxidants do?

It’s a fairly complex mechanism, but a process called oxidation can cause damage to cells using molecules called free radicals. Antioxidants, as the term implies, help stop oxidation. This means it improves the health of all of our cells, and explains why antioxidants have such wide-ranging health benefits.

What Are The Benefits of NAC (N-acetyl cysteine) and Why Should You Take an NAC Supplement?

NAC (N-acetyl cysteine) is mostly known for its ability to replenish glutathione, an essential antioxidant that reduces free radicals, which cause oxidative stress. You could also supplement with glutathione directly, and you can check out our guide on the best glutathione supplements for that.

However, NAC supplements in the right populations have been shown to increase glutathione levels, which may have an array of health benefits.

Improved Immune, Lung, Liver, and Heart Health

Glutathione works wonders for your immune health, which is why taking a NAC supplement can help fight against a variety of illnesses affecting the lungs, liver, heart, and brain.

For example, one study showed that taking NAC can help treat liver disorders because of its antioxidant-boosting qualities. Another study on NAC also showed that it alleviated symptoms of chronic lung disorders like Chronic Obstructive Pulmonary Disease (COPD) or chronic bronchitis by helping to clear mucus from the passageways. Its research to improve lung function is among the most promising for this nutrient.

In addition, taking N-acetyl cysteine can fight against heart disease because its glutathione-boosting qualities help decrease oxidative damage (which can lead to heart disorders).

NAC also plays a role in kidney and liver detoxification.

May Improve Memory

Its ability to encourage glutathione production also makes NAC good for memory retention. In fact, research shows that taking N-acetyl cysteine can potentially slow the progress of Alzheimer’s disease and Parkinson’s disease.

Reduces Symptoms of Mental Health Disorders

Lastly, NAC has been linked to improving fertility and reducing symptoms of mental health disorders such as schizophrenia, bipolar disorder, obsessive-compulsive disorder, and substance abuse. It’s becoming increasingly popular in psychiatric contexts, and since it’s a safe, over-the-counter supplement, those with mental health disorders can see improvements without much downside.

So, yeah. This supplement truly can treat a lot. There’s even research with NAC on specific disorders like trichotillomania, or obsessive hair pulling.

However, you don’t need to have a health disorder to benefit from taking a NAC supplement. In fact, its wide-ranging effects speak to its breadth of benefits for so many people.

The bottom line is it prevents cell damage and boosts immune health, and in that process can improve almost everything about our overall health.

The Best 11 NAC (N-Acetyl Cysteine) Supplements

*Note: We do have affiliate links throughout this article, which means we receive a commission if you purchase from any of our links. This supports our mission to bring complicated health and fitness info in an entertaining package. And it keeps us from putting up annoying things like banner ads. Those suck.

Now let’s get into the best NAC supplements on the market. Note, every product on our list is GMP-approved and third-party-tested.

1) Slim Sciences NAC- 600

Buy 1 + Get 2 Free

Okay, here’s the deal: NAC is not a complicated supplement. What you should look for is simplicity, quality, and purity, at a great price.

Slim Sciences NAC-600 covers all of that.

The only ingredient besides the vegan capsule is simple, pure, NAC. There are no filers. 

Second, this product is third-party tested and manufactured in the USA.

It’s gluten-free, non-GMO, vegan-friendly, gluten-free, and soy-free. You don’t have to worry about many common allergens.

A few reasons give Slim Sciences NAC-600 a slight edge over other high-quality, pure products. First, the 600mg dose is slightly higher than the standard 500mg dose. In most studies showing NAC’s powerful benefits, they used higher doses.

Second, with a buy 1 get 2 free offer they’re running right now, it makes their high-dose, high-quality product a deal that’s tough to beat. 

Finally, it’s backed by a 180-day money-back guarantee.

That’s why Slim Sciences NAC-600 tops our list.

2) Double Woods N-Acetyl Cysteine

double wood best nac supplement

Check Lowest Price

Double Wood’s NAC is also a high quality product at a great price. Every capsule contains 500mg, which is a solid dose, and with 210 capsules per bottle you’ll have enough NAC to last for a long time.

When it comes to quality and purity, Double Wood checks all of the boxes. Each of their products is tested for purity and manufactured in the USA. You can even view the third-party lab results of each product.

It’s gluten-free, non-GMO, vegan-friendly, and soy-free. 

Finally, it’s a great price. You can also buy multiple bottles and save. On top of that, you can get $15 off purchases of $100 or more at Double Wood with the code, HEALTH 15 and by using this link. While you’re there, stock up on their wide selection of single-ingredient products.

Finally, Double Wood offers a 100% money-back guarantee

For all of these reasons, Double Wood NAC is our #2 pick.

3) Seeking Health NAC

Check Lowest Price

Seeking Health NAC contains the active “L” form of NAC, N-Acetyl-L-Cysteine. In the metabolism of NAC into glutathione, it’s the cysteine that’s important, and Seeking Health’s product recognizes this by having cysteine in its free-from.

It’s manufactured in the USA and third-party tested not just for purity and potency, but also for heavy metals and microbials.

With 500mg per veggie capsule and 90 capsules per bottle, with their BOGO offer, Seeking Health NAC gives you a great value from a top-notch company.

4) NOW Foods NAC


Check Lowest Price

First, NOW Foods is one of the most reputable, long-standing supplement companies out there. In terms of overall quality and efficacy, you know that what’s one the label is exactly what you’re getting.

Second, this NAC supplement contains selenium and molybdenum, which are minerals that protect against cell damage and help the body process protein, respectively. In fact, a lot of research shows positive impacts when NAC is combined with selenium, like this study Like NAC, selenium and molybdenum also defend your cells, and they may work in tandem to be even more effective.

Selenium is a powerful supplement in its own right, which you can learn more about in our guide to selenium supplements.

NOW’s NAC supplement is also a great value. It’s only a few bucks (NAC is not expensive to produce, so no products should cost that much), and you get an efficacious 600mg dose per serving.

Plus, the capsule is vegetarian-friendly.

Each bottle contains a fifty-day supply if you take the recommended amount of two capsules per day.

5) Pure Bulk NAC (Best Bulk)

PureBulk NAC

Check Lowest Price

Capsule form is definitely the most popular way to take NAC, however, you can also find it in powder form. Pure Bulk NAC powder gives you a great value for pure, high-quality NAC.

NAC is completely tasteless, but I still recommend throwing it into a protein shake, smoothie, or other drink. 

Pure Bulk has an impressive selection of single-ingredient supplements in powders and capsules.

6) Thorne Research NAC

Thorne NAC

Check Lowest Price

Thorne’s NAC supplement is a good gluten-free option. Each bottle includes ninety capsules containing 500 mg each, and the recommended amount varies from one to two capsules a day. This variation allows you to try out different doses and see what works best for you.

7) Life Extension N-Acetyl-L-Cysteine

life extension NAC

Check Lowest Price

With sixty capsules containing 600 mg each, Life Extension’s NAC supplement is the most affordable and reliable product on the market. It is another gluten-free option, and the capsules’ ingredients are easy to absorb. Plus, it has over 4,000 positive reviews.

8) Natural Factors NAC

natural factors n acetyl l cysteine

Check Lowest Price

If you want a supplement brand that provides options, Natural Factors is for you. Their NAC supplement comes in both 500 mg and 600 mg bottles. The recommended amount ranges from one to three capsules a day, so you can safely test out what dose works best for you.

It also lives up to its “natural” brand name. It is vegetarian-friendly and contains no artificial colors, preservatives, sweeteners, soy, or dairy.

9) Dr. Mercola NAC with Milk Thistle

Dr. Mercola NAC with Milk Thistle

Check Lowest Price

Dr. Mercola’s NAC supplement contains 300 mg of milk thistle in each capsule, which is a plant derivative that improves liver functioning. This combined with 500 mg of N-acetyl cysteine makes Dr. Mercola’s the best NAC supplement on the market for specifically targeting the liver.

10) Mason Natural NAC

Mason Natural NAC

Check Lowest Price

If you are looking for the most affordable cost, Mason Natural’s NAC supplement is for you. It is free of peanuts, tree nuts, dairy, egg, starch, sugar, fragrances, and preservatives. In other words, it has the N-acetyl cysteine you’re looking for (500 mg of it) and nothing else.

11) Lake Avenue Nutrition NAC

lake avenue nutrition NAC

Check Lowest Price

There aren’t many bulk options for N-acetyl cysteine supplements on the market. Lake Avenue Nutrition’s NAC supplement, however, is a great substitute. It contains 120 capsules with 600 mg each to provide a four-month supply. It also contains selenium and molybdenum, which enhances the supplement’s strength.


Are there any drawbacks?

N-acetyl cysteine is considered to be a safe supplement. However, the supplement could interact with certain blood thinners and blood medications, so you should consult a health care provider before taking NAC.

N-acetyl cysteine can cause side effects like nausea, vomiting, diarrhea, rashes, and tiredness if taken in large doses. It has also been reported to have an unpleasant odor.

Experiences vary from person to person. If you want a supplement that encourages whole body health, a NAC supplement is definitely worth a try.

Is it Better to Supplement With Glutathione, Glycine, or NAC?

Obviously, the answer to this is it depends. However, to make your decision it can help to understand the mechanisms at play. While complex, this jist is that NAC helps accelerate taking the broken-down components of glutathione, and turning them back into glutathione. In theory, this increases glutathione in the blood. This is good news, and based on the research, NAC definitely increases glutathione production overall.

But why not just increase glutathione directly? Well, many glutathione supplements get broken down in the digestion process before they make it to the blood, so if you choose glutathione, you’ll want to choose a product that focuses on bioavailability. 

We cover which products we think are the best in our article on the top glutathione supplements

Glycine also plays a “building block” role in glutathione production. It also has an array of other benefits like improving sleep quality. You can learn more about glycine at this article on the best glycine supplements.

Does NAC Support The Immune System?

Since NAC can raise glutathione levels, and glutathione is a powerful antioxidant, there is compelling evidence to support the claims that NAC can improve your immune health.

Can NAC Help With Marijuana Overuse (Cannabis Use Disorder)?

As we said, NAC has a wide range of benefits. For example, a dose of 2,400mg per day of NAC has been shown to support cannabis use disorder, per recent research on NAC and substance abuse disorders. The proposed mechanism for this may even extend to support other addictions or abuse disorders.

Isn’t NAC a Prescription Drug?

NAC is such a powerful simple molecule, it even has uses as a prescription drug. For example, it’s often used to treat Tylenol (acetaminophen) poisoning. It has been investigated for an array of health conditions.

This means NAC dietary supplements have entered that gray area with the FDA between “drug” and “supplement.”

Disclaimer: Talk to your healthcare provider before taking any dietary supplement, including NAC.

About the Author

David is a writer and strength coach and co-owner of Roman Fitness Systems. In addition to helping run RFS, he's also the head editor for, the official website of the Strength and Conditioning Association of Professional Hockey. You can also check out his Instagram, he's pretty easy on the eyes.

Leave a Comment