And Much More.
✓ 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.
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.
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.
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Best NAC Capsules: Slim Sciences NAC-600
Best NAC for Cognitive Performance: BioPharma Scientific NanoNeuro
Best NAC for Hangovers: Morphogen PARTY
Best NAC for Heart Health: Solaray PQQ CoQ-10 with NAC & Glutathione
Best NAC for Liver Health: Dr. Mercola NAC with Milk Thistle
Best NAC Powder: Pure Bulk NAC
Best NAC Gummies: Etta Vita N-Acetyl Cysteine Sugar-Free Gummies
(Yes, that’s right, Gummies!)
Now let’s get into the best NAC supplements on the market. Every product on our list is GMP-approved and third-party-tested. Every capsule product uses 100% vegetarian capsules.
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 tough deal to beat.
Finally, it’s backed by a 180-day money-back guarantee.
That’s why Slim Sciences NAC-600 tops our list.
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.
NanoNeuro stands out for congitive performance because, in addition to the full 600mg dose of NAC, it also has 200mg of l-theanine. l-theanine is a naturally-occurring amino acid that’s especially abundant in green tea. It’s been shown to support with focus and relaxation, and for “taking the edge off” of caffeine.
If you’re taking NAC for cognitive function, memory, or focus, then this is the option for you.
They’re also offering 15% off for RFS readers when you use our link.
This product is very different from all of the others on this list. It’s not a pure NAC supplement, rather it’s a comprehensive blend designed for “Pre-Party Harm Reduction.”
It includes 400mg of NAC per serving along with over a dozen other ingredients.
If you’re taking NAC specifically for your out-in-the-town shenanigans, this is the best product out there.
It’s designed to minimize the negative impact of a night out, so you can have fun at night and wake up feeling fresh.
With ingredients designed to reduce harm from alcohol and other festivities, PARTY will help your hangovers before they come.
Morphogen Nutrition is one of the most innovative companies in the supplement space, and PARTY is a one of their latest examples of pushing the boundaries.
This product is also different from the rest on our list. It contains 4 powerful antioxidants designed to help support normal cardiovascular function and cellular health: PQQ, CoQ10, NAC, and glutathione.
Together, they offer a potent combination for nutritional support for cellular and heart health.
A 2018 meta-analysis that looked at research on coronary artery disease showed that CoQ10 supplementation has reduced total cholesterol levels. This suggests that it can support heart health. Other research suggests it may have cardiovascular protective effects. It has even been used as a supplement to conventional treatment for those with heart disease.
This antioxidant combination makes it the best choice on our list if your goal is heart health specifically.
This is probably the best NAC supplement for children. That’s for a few reasons. First, they come in naturally-flavored, sugar-free gummies. So that’s an obvious win.
Second, each capsule only contains 150mg. This dose is probably low for adults, but for kids, it’s more suitable. While the dose is low, it comes at a great price point, so it’s overall still a great value.
Etta Vita has strict testing standards. This product is non-GMO, vegan, and gluten-free.
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.
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.
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.
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. So if you’re looking to take NAC for fatty liver or other liver reasons, this is the one for you.
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.
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.
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.
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.
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.
NAC 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.
NAC supplements in the right populations have been shown to increase glutathione levels, which may have an array of health benefits.
NAC’s link to immune health is due to its ability to increase glutathione levels. Glutathione in turn has an array of antioxidant properties, as examined in studies like these.
Because of this, NAC also shows links to lung, liver, heart health, and much more.
NAC is actually an FDA-approved treatment for acetaminophen poisoning (Tylenol). This also points to its larger capacity to support liver detoxification. For example, one study showed that taking NAC can help treat liver disorders because of its antioxidant-boosting qualities.
This is incredibly remarkable, and also why it may help with other conditions like fatty liver disease.
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).
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.
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.
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 healthcare 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 support, a NAC supplement is definitely worth a try.
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.
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.
One study found that NAC treatment helped people fall asleep faster.
Another study found that NAC supplements improved deep sleep and overall sleep efficiency in patients with obstructive sleep apnea syndrome (OSAS).
These are encouraging and promising outcomes, and are making NAC popular as a part of a sleep supplement stack alongside ingredients like magnesium and l-theanine.
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.
Research on NAC and COVID-19 is still ongoing and the outcomes are unclear. This review gives a great overview of the current evidence.
Some studies have shown that NAC administration in patients with COVID-19 pneumonia reduces the risk for mechanical ventilation and mortality.
That said, NAC is NOT a treatment for COVID-19. If you have COVID-19, you should talk to your healthcare provider about treatment options.
NAC, or N-Acetyl Cysteine, is a modified form of the amino acid Cysteine. Think of it as Cysteine’s cooler, more effective sibling. While Cysteine is naturally occurring and can be found in high-protein foods like chicken, turkey, and yogurt, NAC is its more stable, supplement-friendly form.
The “N-Acetyl” part is like the VIP pass that allows Cysteine to enter the club of your cells more efficiently. This modification enhances its bioavailability, making it easier for your body to absorb and utilize. Plus, NAC has unique antioxidant properties and is often used for its ability to replenish levels of the master antioxidant, glutathione. So, while Cysteine is great and all, NAC is the one you invite when you want the party to be a hit.
The short answer is yes, you can take Vitamin C and NAC together, and doing so can actually offer some synergistic benefits, since they both support antioxidant activity.
This is covered more in-depth in this study published in Nature.
Most studies use between 600-1200mg. This is why we love a product like Slim Sciences, which starts at that 600mg dose.
NAC may both support cognition and sleep, placing it in an interesting situation. Because of this, we recommend you take it whenever is most convenient for you. For the time of day to take NAC, there are no wrong answers.
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.” However, it terms of how it interacts in the body, it’s generally safe and without excessive side effects common with pharmaceutical drugs.
Disclaimer: Talk to your healthcare provider before taking any dietary supplement, including NAC.