There is no fountain of youth or silver bullet that’s going to stop aging and cure all that ails you. That’s the bad news. The good news is that certain supplements support aspects of our health that have massive ripple effects throughout the rest of our being. N-Acetyl Cysteine (NAC) may prove to be one of those supplements.
Clinical research into NAC has yielded promising results, especially in trials investigating its use for respiratory health and its purported antioxidant power. Its most commonly touted benefit is its ability to increase your body’s glutathione levels, which is a powerful antioxidant. And antioxidants have seemingly endless positive effects.
Because of its tremendous potential, dozens of supplement manufacturers sell NAC in capsule or powder form, making it tough to know which company offers the best product. Our guide walks you through everything you need to know and gives you recommendations for the best possible product for your needs.
If you’re pressed for time, here are our top recommendations:
Wholesome Story NAC supplement contains clean, scientifically-backed ingredients that benefits both men and women.
Wholesome Story products are all third-party tested, Clean Label Project-certified, and made in the US. Get free shipping on orders over $40, and take $10 off with code INNERBODY.
Current Deals: Take $10 off with code INNERBODY
As we set out to evaluate the various NAC supplements out there, it was necessary that we keep these criteria front of mind at all times. They guided us to our top pick, and you would also be wise to consider them.
Winner: Wholesome Story
What makes one NAC supplement more effective than another? At first glance, it might seem that NAC supplements are mostly created equal and that higher doses yield greater efficacy regardless of other factors. But things like the purity of an NAC supplement — as verified by third-party testing — and even the addition of supporting ingredients can all play a role in efficacy. Absorption is another factor we explore below, as powder forms of NAC offer faster absorption, as well as capsules that may dissolve at different rates.
Winner: Life Extension
The price tag on NAC supplements only tells part of the story. We understand that having the capital to invest in larger quantities to access overall savings isn’t in everyone’s budget. But there are certain opportunities among NAC supplements where bulk ordering — especially in powder form — makes a huge difference in cost per dose.
We’ve put a chart below to give you a sense of those savings opportunities. Prices include subscription savings where available.
|Cost per bottle||Dosage||Servings||Total grams NAC||Cost per gram|
Winner: Wholesome Story
The safety of NAC, in general, is well supported by clinical evidence. Few adverse reactions have been reported in dozens of clinical trials. When there are reactions, they tend to be rather mild. So, to compare the safety of one brand to another, we looked at things like manufacturing practices, third-party testing, cross-contamination potential, country of origin, and dosage.
Winner: Life Extension
While the experience of purchasing a supplement online and taking it daily is largely the same across the companies in our guide, there are little things that might make some more convenient than others. In evaluating convenience, we considered subscription discounts and flexibility, website navigation, return policy, and capsule size.
NAC stands for N-Acetyl cysteine. It’s a precursor for cysteine, an amino acid used throughout the body. In addition to using it as a building block for proteins, your body turns cysteine into glutathione, a powerful antioxidant.
Numerous clinical studies have looked at NAC’s potential to support various ailments, from pulmonary issues to diabetic cardiac function. Study after study points toward improvements in multiple systems and an increase in glutathione in participants who received NAC.
For the most part, NAC supplements are perfectly safe. That said, there are a few potential side effects to consider. These are typically rare, with many reports generated from intravenous NAC studies. They include:
- Difficulty breathing
- Hives or itching
- Trouble swallowing
As with any supplement, we recommend that you talk to your doctor before introducing anything new to your daily regimen.
Unlike some other age-fighting supplements, NAC can cross the barrier into your cells without the help of transporters. That means it’s more bioavailable and will yield greater results.
Once in the cell, your body quickly converts it to cysteine, which triggers the production of glutathione (GSH). And GSH is an incredible destroyer of free radicals that could cause oxidative stress on your cells, which would otherwise prematurely age them and even potentially kill them off.
In addition to promoting the production of GSH, cysteine acts as a vasodilator in the body’s nitric oxide system. This increases circulation, delivering more beneficial nutrients to systems that need them and potentially helping with disorders like erectile dysfunction.
Common uses for NAC
While glutathione production is a cornerstone benefit of NAC, doctors employ it for various treatments. Some are well-studied and understood, while others are known to work though their exact mechanisms of action remain something of a mystery. A few uses are limited to animal trials and aren’t the top reasons to reach for an NAC supplement. Still, they shine a light on its tremendous potential.
Intravenously, NAC is the best-known cure for acute acetaminophen overdose, thanks to its ability to support the liver’s natural detoxification abilities.
There is also evidence to suggest that NAC can inhibit the symptoms of obsessive-compulsive disorder and other mental health issues like bipolar disorder and depression. This is primarily due to NAC’s influence on glutamine, a critical neurotransmitter.
Several studies have been conducted on COPD patients to determine the efficacy of NAC in limiting their symptoms. One of the ways it does this is by acting like an expectorant, which can help clear phlegm from airways.
Blood sugar regulation
While the studies supporting this benefit haven’t yet expanded to include humans, animal trials indicate that NAC can decrease inflammation in fat cells and effectively increase insulin resistance.
Oxidative stress is one of the first things specialists may point to if their patients are having difficulty conceiving. Often, this leads to recommended changes in diet, but supplementation with NAC may help prevent free radicals from damaging reproductive cells. There is also evidence that NAC can help treat polycystic ovarian syndrome in women.
Best overall and cleanest ingredient list
- Clean Label Project-certified
- No added ingredients whatsoever
- 90-day money-back guarantee
- Third-party tested
- One bottle lasts up to four months
- Made in the USA
- Free shipping on orders over $40
- 10% off with subscription
- Take $10 off with code INNERBODY
- Dose is average among NAC supplements
- Has a strong sulfur smell
Wholesome Story is a relatively young company started by a married couple just after the birth of their first child in 2016. Their selection of supplements focuses on potential polycystic ovarian syndrome (PCOS) treatments. Still, many of their supplements — like NAC — offer additional benefits to users. Here’s a quick list of their current offerings:
- Myo- and D-chiro-inositol (capsules and powder)
- Myo- and D-chiro-inositol with folate and D3
- Saw palmetto
- Zinc, magnesium, and B6
Since most of these supplements benefit men and women alike, you certainly don’t have to have PCOS to use them.
If you are concerned about PCOS, there is no definitive test for the syndrome, only a process of elimination under the guidance of medical professionals. But the syndrome has profound hormonal effects, and symptoms generally include:
- Irregular or abnormal periods
- Excessive weight gain
- Hair loss or unwanted hair
Given the sensitivity of their target demographic, Wholesome Story takes pains to ensure the quality of their products. They subject each supplement to rigorous third-party testing and are one of the few NAC producers to earn a certification from the Clean Label Project. They achieve this partly because they have nothing in their NAC supplement other than free-form NAC housed in a capsule made only of methylcellulose.
One bottle of Wholesome Story NAC contains 120 capsules — a 4-month supply — and costs $29.95. You can save 10% by subscribing, which brings your cost down to $23.36 per bottle.
Shipping from Wholesome Story is free on orders over $40, so you’ll need to add another supplement or buy larger quantities to qualify. You also get 90 days to see if the product is right for you, thanks to the company’s straightforward money-back guarantee.
Best budget pick and best money-back guarantee
- Extremely low price
- Free shipping with auto-ship program
- One-year return policy
- Reasonably small capsules
- Gluten-free and non-GMO
- Subscription doesn’t offer a lower price
- Stabilized with vegetable stearate
Life Extension offers a dizzying array of supplements that cover everything from hormonal health to inflammation management. They’re consistently one of the least expensive options across many market categories, particularly when you utilize their subscription model.
Life Extension NAC is a relatively straightforward version of the supplement, though it contains a couple of extra ingredients to extend its shelf life. For some, these are wholly innocuous, but other people might look to competitors to find an even cleaner product. That said, Life Extension offers certificates of analysis for every one of their products, so you can see that their supplements meet quality and purity guidelines. They also offer measurements for the capsule size, so we can confirm that it’s among the easiest to swallow.
One bottle of Life Extension NAC contains 60 capsules, which can last up to two months, depending on your preferred dosage. The cost per bottle is $6.75 whether or not you choose to subscribe. The auto-ship program unlocks free shipping, which would otherwise cost a flat rate of $5.50 in the US.
Life Extension offers one of the most extended guarantees of any NAC manufacturer, covering your purchase for an entire year.
- Large 900mg dose
- Vegetarian capsules
- Made in the USA
- Subjected to third-party testing
- Free shipping on orders over $75
- On the pricey side
- Poor return policy
- Consultations are also very expensive
Root is a somewhat unusual company in this space. While many supplement manufacturers stick to selling physical products, Root is continuously expanding to deliver targeted medical care and professional advice in a small number of states. They offer meal plans shipped right to your door and consultations with dieticians and other professionals who can help you attain health and wellness goals.
You can purchase any of their supplements independently without being a member or signing up for any special classes. And their supplements can ship anywhere in the US regardless of telemedicine regulations. Their target demographic appears to be women, but nothing stops anyone from making good use of their products.
Root’s NAC supplement is simple. It contains NAC in a 900mg dose and is housed in a vegetable cellulose capsule with stearates for stabilization. Root’s recommended dosage is 1-2 capsules per day, and we think one capsule per day should be enough for most people, given the amount of NAC in each.
One 120-capsule bottle of Root NAC costs $42 and lasts up to four months, but you can save 10% and pay $37.80 when you subscribe.
Shipping from Root is free on all orders $75 and up, with a $6 flat rate for orders under that. In-stock orders received by noon EST will ship the same day.
Best high dose
- Large 1,000mg dose
- Bulk and subscriptions savings available
- Made in the USA
- Manufactures in a GMP-certified facility
- Free of soy, gluten, and GMOs
- Free shipping on all domestic orders
- Guaranteed for only 30 days
- Odd serving count per bottle
- Testing is internal
Double Wood has numerous supplements available at reasonable prices that put them right in the middle of the market. The quality is high, and the subscription savings are significant. In addition to their NAC supplement, they offer products for the following areas of wellness:
- Focus and motivation
- Anxiety and stress
- Weight lifting
Double Wood categorizes their 1,000mg NAC supplement under their immune system support section. You can purchase a single or double pack, both of which are eligible for subscription savings. Here’s how your options price out:
|Total cost||Cost per bottle||Cost per dose|
|Single pack, one-time purchase||$30||$30||$0.29|
|Single pack, subscription||$25||$25||$0.24|
|Double pack, one-time purchase||$50||$25||$0.24|
|Double pack, subscription||$42||$21||$0.20|
One odd thing about Double Wood’s NAC is that each bottle contains 105 doses, which will last you about 3.5 months. This means you won’t be able to count on a recurring date for repeat charges on a subscription.
- Outstanding price per gram
- Also sold in capsule form
- Third-party testing
- Certificates of analysis available
- No other ingredients than NAC
- Industrial bulk sizes available
- 90-day money-back guarantee
- Free shipping on orders over $50
- No subscription options
- Industrial sizes do not qualify for free shipping
- Capsules contain bovine gelatin
Several companies offer supplements in bulk powder form, but few have quantities as large as what Pure Bulk offers. We also appreciate that the company subjects their supplements to third-party testing and offers customers certificates of analysis to show purity and potency.
A big advantage of purchasing NAC in powder form is that no other ingredients are involved. Capsules usually contain cellulose or gelatin, and many include stabilizers like silicon dioxide. With a pure powder, NAC is all you get. And powdered supplements have the potential to absorb more quickly, as they can start making their way into the bloodstream as soon as they hit your mouth.
You can also purchase NAC from Pure Bulk in capsule form, but between the price and the presence of bovine gelatine, you’d be better off looking elsewhere for capsules.
Pure Bulk sells their NAC powder in the following sizes:
|Cost||Doses||Cost per 750mg dose|
*It may look as though the 500g and 1kg amounts cost the same per dose, but this is a reality of rounding. The 500g dose’s price was rounded down to $0.07, whereas the 1kg dose’s price was rounded up.
- Made with milk thistle
- Contains broccoli sprout powder
- Made in a GMP-certified facility
- Two-capsule serving size
- Dose is below average
- Testing done internally
While we spent much of our time evaluating NAC supplements looking for the fewest possible additives, the milk thistle and broccoli sprout powder in Dr. Mercola’s NAC are welcome additions. Milk thistle has long been associated with liver health, and some studies back that up. Given NAC’s liver-boosting capabilities, the combination makes a lot of sense.
The only downside to their formula is the dose. Most NAC supplements offer a 600mg dose; while 500mg isn’t unheard of, it is a little shy of average. Hopefully, adding milk thistle and broccoli sprout powder makes up for the difference.
Dr. Mercola also tests their products rigorously, even if that testing is done internally. They check for heavy metals, purity, and potency and pledge not to use packaging materials that don’t biodegrade or recycle.
We found iHerb to be a great place to get Dr. Mercola products. Their NAC supplement on iHerb costs $21.49 for a 60-capsule bottle. You can also subscribe to save 5% and pay $20.42. Auto-ship orders and orders over $20 receive free shipping, so you won’t incur shipping charges no matter your preferred purchasing method.
Do NAC supplements work?
According to a large quantity of research, NAC supplements work. At the very least, they’ll increase the levels of glutathione (GSH) in your blood, and increased GSH concentrations have been shown to reduce oxidative stress all over the body. That provides anti-aging and disease-fighting effects.
What are NAC supplements good for?
NAC supplements can help treat various ailments and protect the body from oxidative stress that could speed up aging or encourage disease. Some of the most common reasons people take NAC supplements include
- Inhibiting free radicals
- Boosting immunity
- Improving mental health
- Managing PCOS
- Enhancing fertility
Are NAC supplements dangerous?
NAC supplements are very safe. They have a short list of possible side effects, most of which are exceedingly rare and mild. They include digestive upset, especially as your body acclimates to the supplement. There is also a small risk of breathing difficulty, fever, or trouble swallowing, but these effects are more often seen in intravenous administration for acetaminophen overdose.
What’s the best dose for NAC?
The best dose for NAC is the lowest possible dose that still provides the maximum benefit without adverse effects. The same is true for most supplements and medications. Most NAC supplements offer doses around 600mg, which is well within the range of clinical studies. But other studies have demonstrated few to no adverse reactions at doses approaching 2.5g. With that in mind, you could opt for a high-dose NAC supplement and have no problem with it.
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Additionally, like all health-related content on this website, this review was thoroughly vetted by one or more members of our Medical Review Board for accuracy.