N-acetylcysteine, known by its more common abbreviation NAC, is a supplement that can be used for everything from treating upper respiratory infections to improving mental health issues to protecting your lungs to helping you kick addictions.
It was originally developed as a medical intervention to treat acetaminophen overdose, but has found far-reaching application as a treatment for a great number of health problems, and is an area of active research.
Need a NAC supplement that’s got the right dosage and the right ingredients? We’ve got you covered. Our researchers have ranked the ten best NAC supplements on the market.
Last updated: March 28, 2023
NAC supplements considered: 25
Hours of research: 37
Experts reviewed: 7
Scientific papers referenced: 16
1. NOW NAC
NOW NAC provides 600 mg of NAC, alongside two critical trace elements for proper hormone and protein synthesis, molybdenum and selenium.
The supplement is encapsulated in a caplet made of vegetable cellulose and doesn’t include any unnecessary binders or fillers, making it a great choice.
2. Life Extension N-Acetylcysteine
Following the standard clinical trial protocol, Life Extension makes 600 mg capsules of NAC. The supplement design is very clean, with just a few ingredients to hold the vegetarian capsule together, and with the quality that Life Extension is known for, this NAC supplement is an excellent choice.
3. Integrative Therapeutics NAC
Integrative Therapeutics offers a high-grade NAC supplement that’s super-minimal in its design. In total, it’s got only three ingredients: N-acetylcysteine, gelatin, and rice flour.
If you don’t want any unnecessary ingredients in your NAC supplement, this is definitely the way to go. The only drawback? The gelatin capsule isn’t vegetarian-friendly.
4. Jarrow Formulas NAC Sustain
Jarrow Formulas delivers a standard 600 mg dose of NAC, but what makes this supplement unique is its capsule. It uses a few binders and excipients to bind part (but not all) of the NAC in a slower-releasing form.
The effect is that some of the NAC gets released immediately, while the rest of it diffuses more slowly into your bloodstream.
This is hypothetically an advantageous way to deliver NAC, though most scientific research does not use this kind of formulation. Purists might not like the need for additional ingredients to achieve this slow/quick release effect, but it could be a good choice if you want sustained levels of NAC throughout the day.
5. Thorne Research NAC
The dosage in Thorne Research’s NAC supplement is somewhat lower than the usual, at 500 mg. While this is a bit lower than you’d want for fighting addiction cravings, it’s perfect for post-workout recovery, where moderation in antioxidant levels is the name of the game.
6. Nutricost NAC
Nutricost’s NAC supplement has just a couple of extra additives, but they’ll only be an issue for the strictest of supplement purists.
The main advantage to this NAC supplement is that the bottle provides 180 capsules, a lot more than some other brands out there, so if you’re in it for the long haul, this is a good choice.
7. Mary Ruth’s NAC
Mary Ruth’s makes a super simple and to-the-point NAC supplement: 500 mg, vegan-friendly capsules, and a few binders to hold everything together. That’s it! For people who want a no-frills, middle of the road dosage NAC supplement it’s a very solid option.
8. Pure Encapsulations NAC
Pure Encapsulations makes a 600 mg NAC supplement contained in a vegetarian-friendly cellulose capsule. Instead of inert binders like rice flour, this supplement uses ascorbyl palmitate (a vitamin C derivative) as both a binder and preservative.
Some may not like this slightly more exotic ingredient in their supplement, but aside from this, the design is pretty clean.
9. Source Naturals N-Acetylcysteine
Source Naturals makes a high-dose NAC supplement with 1000 mg of NAC per tablet. Unlike most of its competitors, it is pressed into a slow-dissolving tablet instead of a fast-dissolving capsule.
This adds a lot of binders that need to be included to hold the materials together, but it is likely the most advantageous way to deliver a higher dose of NAC. It’s a solid go-to if you need the high dosage, but others are better when it comes to the standard 600 mg dosage.
10. Swanson NAC
Swanson NAC has the standard 600 mg dosage, though it also has a couple of extra ingredients and isn’t vegan-friendly due to its gelatin capsule. Aside from that, it’s a solid product, but doesn’t stand out from the crowd.
Best NAC overall: NOW NAC
NOW NAC delivers a solid dose of NAC alongside trace minerals for optimum enzyme function. The capsule is vegan-friendly and the supplement design is super-clean—it’s a great all-around pick.
Best NAC for anxiety and mental health: Life Extension NAC
Life Extension delivers the same 600 mg dose of NAC that virtually all clinical trials use, so it’s perfect if you are modeling your supplementation routine on the latest scientific research.
Best NAC for cravings: Life Extension NAC
Studies on using NAC to suppress cannabis or cocaine cravings typically involve twice-daily doses of 600 mg of NAC. Taking these 600 mg Life Extension NAC capsules twice a day is the perfect way to mimic the best research if you want to use NAC to control your cravings.
Best NAC for older adults: NOW NAC
NOW NAC stands out for older adults thanks to its inclusion of selenium and molybdenum, important trace minerals that many older adults are lacking. These elements play a critical role in the enzymatic function that NAC assists with, making NOW NAC an easy choice.
Best NAC for workout recovery: Thorne Research NAC
Because it’s a glutathione precursor, NAC can help boost your recovery after tough workouts, especially if your natural glutathione levels are low. If this is your aim, keep the dosage moderate—go for Thorne Research NAC, which has 500 mg of NAC per capsule.
Best NAC for immune strength: Life Extension NAC
Life Extension NAC excels for immune strength for the same reasons it’s well-suited for cravings and mental health: the precise dosage and ultra-pure formulation.
Who should buy NAC?
The benefits of NAC span both physical and mental performance. NAC’s primary application is boosting your antioxidant levels through its ability to upregulate glutathione production, but despite this seemingly narrow application, NAC has a wide range of potential health applications. The people best-suited for adding a NAC supplement include:
People looking to boost their immune system function. NAC is great for boosting your immune system if you have an infection, particularly infections that affect your respiratory tract like the common cold or the flu. Research supports its ability to prevent infection and augment the function of your body’s immune system.
People who want to kick an addiction. Research shows that NAC can prove useful when trying to kick addictions to cocaine, cigarettes, and cannabis. NAC has been around for a long time, but researchers are taking a serious look at its ability to help people quit addictions: the mechanism by which it works is still not fully understood, but early results are promising.
People who want to control feelings of depression and anxiety. NAC exerts powerful beneficial effects on your brain, by protecting cells against oxidative damage, reducing programmed cell death, and shifting the balance of neurotransmitters in your brain. For this reason, it’s been studied as a way to improve feelings of stress, anxiety, or depression.
How we ranked
With our NAC rankings, we were mindful of the extremely broad range of applications for NAC supplements, from endurance exercise performance to treating addiction and mental health problems.
As such, we wanted to make sure the products on our list were pure, effective, and well-suited for this wide range of potential uses. Here are the criteria our research team used to ensure that the NAC supplements on our list retained this wide spectrum of uses.
Only supplements with NAC as the sole active ingredient. Starting from all of the NAC-containing products from well-regarded manufacturers, we narrowed the field to NAC supplements whose sole active ingredient was N-acetylcysteine.
Our only exception to this was products which included trace amounts of minerals that are important in the enzymatic processes surrounding NAC’s biological pathways, such as molybdenum and selenium.
Other combo supplements that included NAC alongside other supplements (even good ones) got dropped, since having a second ingredient come along for the ride might not be desirable for every application.
NAC dosage between 500 and 1000 mg. After surveying the scientific literature on effective dosages for NAC for its wide-ranging applications, we narrowed our field further so it contained only NAC supplements that contained between 500 and 1000 mg of NAC per capsule.
Most applications call for 500 to 600 mg, taken twice daily, but a few studies include higher doses—we made sure we kept at least one high-dose NAC option on the list for exactly this reason.
Clean supplement design and pure ingredients. From here, we focused on purity and clean supplement design. The best performing NAC supplements were those that used very little in the way of binders, fillers, and extra or unnecessary ingredients.
Supplements that were bloated with extras were dropped. Finally, we took note of any distinctive supplement design features, such as the extended-release formulation used by Jarrow Formulas.
Some users who want to sustain high levels of NAC throughout the day might find a supplement like this useful, while others may want to hew as close to the clinical research recommendations as possible.
Fortunately, doing either is an option with our final rankings, which represent the purest and highest-quality NAC supplements on the market right now.
Q: What is NAC used for?
A: NAC is one of the most versatile supplements out there, because of its wide range of uses. It’s been used in scientific research to boost aerobic endurance, improve cognitive function, and speed recovery from infections.
But those aren’t even the most interesting applications of NAC—the latest research published in the last few years is examining NAC as a potential treatment for mental health issues ranging from depression and anxiety to addiction and schizophrenia.
Q: Can NAC help anxiety?
A: NAC as a treatment for anxiety has strong empirical backing from animal model studies—research on both fish (9) and mice (1) supports an anxiolytic (anxiety-reducing) effects, and some case studies have explored NAC as a treatment for individuals with serious anxiety problems.
The biological basis of NAC as an anxiety treatment is fairly strong too, based on what’s known about the neurological effects of NAC supplementation (2).
While there have not been any large, high-quality randomized controlled trials of NAC for anxiety yet, it appears that the time is ripe for one—within a few years, there is likely to be much more evidence on this front.
Q: Can NAC help depression?
A: NAC has been examined in a number of studies as a possible treatment for depression. A recent review article published in 2016 examined the results of five different clinical studies on NAC for depression (3).
The review, published in the Journal of Clinical Psychiatry by a team of researchers in Australia, found that NAC had a significant effect on lessening the severity of depression symptoms and improving quality of life.
This research is still quite new, but applying NAC to depression and other common mental health problems looks to be a potentially promising avenue of treatment.
Q: How long does it take for NAC to work?
A: Experiments on NAC supplementation typically last at least 30 days, and often much longer, so it pays to wait for at least a few weeks before you decide whether NAC supplementation is helping.
As with any supplement that tries to exert changes on your neurochemistry, you should expect the changes to be slow and gradual. If it’s been a few months and you don’t feel like NAC is helping at all, it might be time to try something else, but if you’ve only been taking NAC for a week or two, definitely give it some more time.
Q: Can NAC help with obsessive compulsive disorder?
A: With the success at treating other mental health issues, like addiction and depression, with NAC, researchers wondered if NAC could also be helpful for obsessive compulsive disorder, or OCD.
OCD is a challenging mental health problem to manage, so a success here would be very valuable. A study published in 2017 tested the effects of NAC versus a placebo on a group of patients with treatment-resistant OCD related behavior (4).
The dose of NAC was quite high, at 3000 mg per day. Despite this, the study did not find any significant differences between the groups in terms of OCD-related behavior.
A secondary analysis did find that NAC helped reduce symptoms of anxiety. The takeaway from this study is that NAC may help with some of the secondary problems associated with OCD, but isn’t likely to help with the primary symptoms.
Q: Can NAC benefit your skin?
A: Due to the antioxidant effects of glutathione, which is synthesized directly from NAC, it’s natural to wonder whether NAC supplementation can improve skin function. We see the same effects with other potent antioxidant agents, like astaxanthin or vitamin C.
With NAC, the evidence is more preliminary, but animal models do suggest that NAC can help protect your skin from ultraviolet light. One study in mice was able to show that NAC supplementation significantly delayed the onset of skin tumors after chronic exposure to ultraviolet light (5).
Whether this translates into anti-aging effects in human skin remains to be seen, but this is a good sign.
NAC shows promise on a number of fronts, from treating and preventing the flu and other viral infections to treating mental disorders and kicking an addiction to cocaine, cannabis, or tobacco.
This simple biological precursor appears to have a wide variety of benefits thanks to its anti-inflammatory and antioxidant powers. In addition, it has potent beneficial effects on neurological function too, which probably accounts for its broad uses for mental health as well.
The usual dosage for achieving these benefits is 600 mg taken in capsule form twice per day (morning and evening). At this dosage level, side effect are relatively rare, but can include flushing, a rash, nausea, and other gastrointestinal issues.
People who take vasodilators shouldn’t take NAC without talking to their doctor first, but aside from this, NAC appears to be fairly well-tolerated.
For BodyNutrition‘s #1 NAC recommendation, click here.