NAC Benefits: What To Know About N-Acetyl Cysteine

N-acetyl cysteine, or NAC for short, is a dietary supplement that may help supercharge your performance and slow down aging. One of the ways NAC supplements work is by helping your body produce an uber-important antioxidant called glutathione, which in turn can help protect against free radicals and keep your cells healthy and strong. Read on to learn all about NAC benefits, how NAC supplements can help support glutathione and how best to take NAC.

What is NAC?

Also called N-acetyl-l-cysteine, NAC is the supplement version of an essential amino acid called cysteine. Amino acids are the building blocks of proteins. Cysteine is one of three amino acids (along with glycine and glutamine) that make up glutathione, an important super-antioxidant found in nearly all of your body’s cells.

In this way, NAC helps your body produce glutathione. And that’s kind of a big deal.

Glutathione is known as the “master antioxidant” because of its prevalence throughout the body and ability to support other antioxidants. The problem is that glutathione tends to decline with age. It can also be reduced by factors like bad nutrition, stress and environmental toxins.

Taking NAC supplements may help replenish your glutathione levels. (Or you can just take a glutathione supplement like Bulletproof Glutathione Force—but more on that later.)

NAC benefits

In the world of healthcare, NAC is used as a medicine that can treat conditions ranging from liver damage to asthma to acetaminophen overdose. It has been well-studied by medical researchers and has an array of potential health benefits.

If you’re thinking of supplementing with NAC, know that it can help with:

Anti-aging

NAC is a favorite supplement in the anti-aging community. One of the benefits of NAC is that it can replenish your glutathione levels by nearly 30%.^[1] Glutathione can help make you more resistant to oxidative stress, slowing down aging at a cellular level.^[2]

Detoxification

NAC can help the body rid itself of harmful toxins. It helps protect cells from toxicity caused by environmental pollutants, including pesticides^[3], heavy metals like lead^[4] and gasoline and diesel fumes.^[5][6]

In a randomized controlled trial, NAC was even found to restore lung function in soldiers exposed to mustard gas.^[7] It’s also a standard at hospitals for treating acetaminophen overdoses and poisons that cause damage through extreme oxidative stress.

Fertility

NAC has been found to improve egg quality and increase pregnancy rates in women with polycystic ovary syndrome (PCOS).^[8] It can also help balance testosterone, one of the main drivers of infertility in women with PCOS.^[9]

NAC may even help reverse weight gain and prediabetes, two common symptoms of PCOS.^[10] In men, NAC improves sperm quality and, in some cases, even reverses infertility.^{[11] [12]} Researchers think this happens because NAC is so good at protecting cells from oxidative damage. Increasing antioxidant status may help keep sperm healthier.

Inflammation

Clinical trials have found that NAC can help support a healthy inflammatory response in the body, which is helpful for relieving symptoms of respiratory conditions like chronic obstructive pulmonary disease (COPD) and improving insulin resistance.^{[13] [14]}

Animal studies suggest that NAC may lower blood glucose levels and improve insulin sensitivity.^[15] In a 2009 rodent study, NAC supplementation was found to lower blood glucose levels and support a healthy inflammation response. We know that chronically high blood sugar can contribute to insulin resistance if left unchecked, but more research needs to be done in humans.

Immune function

Supplementing with NAC can not only help improve immune system health, but it may also help prevent viruses from replicating.^{[16] [17]} However, research is limited. If you’re looking for supplements that help support immune function, consider products with science-backed ingredients like vitamin C, vitamin D and zinc.†

How and when to take NAC, morning or night

Most studies use a dose of between 1200-2400 mg, taken in 600 mg doses throughout the day. If you’re wondering when to take NAC, morning or night, know that it doesn’t matter exactly when you take it. However, you’ll absorb oral N-acetylcysteine supplements best if you take them on an empty stomach, at least an hour away from eating.

If it helps your decision, know that some oral N-acetylcysteine supplements have a strong odor—maybe not the most peaceful thing to take before bed.

Whether you take NAC morning or night, look for a supplement that’s either pure NAC or NAC with vitamin C (the two pair well together). As with any dietary supplement, be sure to check in with your doctor or healthcare provider before you begin taking NAC supplements.

Keep in mind that NAC can result in side effects in some people, especially when taken at high levels. Common side effects of high doses of NAC can include diarrhea, nausea, vomiting and constipation.

If you just want to increase glutathione, reach for a glutathione supplement like Bulletproof Glutathione Force. It uses a liposomal delivery system to support bioavailability, and it’s designed to supplement your body’s own glutathione production. That translates to detoxification, immune health and cellular health to make your body more resilient.†

Related: The Best Supplements for Immune Support

How long does it take for NAC to work?

One of the biggest questions you’ll have before starting to supplement with NAC is: How long does it take for NAC to work?

Research suggests NAC can increase and replenish antioxidant status in about a week.^[18] Like other antioxidant supplements, the longer you take NAC, the more you support your body’s resilience. A 2015 double-blind, placebo controlled study of middle-aged men found reduced signs of oxidative stress after four weeks of taking NAC, including improvements in blood pressure and cardiovascular health.^[19]

Supplements are exactly that: something which enhances something else. NAC supplements are a prime example of one way you can give your performance an extra edge, whether you want to make the most of those anti-aging benefits or boost your body’s glutathione production.

Want to learn more about how glutathione can help support your overall health and wellness? Read our comprehensive guide to glutathione.

This article has been updated with new content.