N-Acetyl Cysteine (NAC) is best known as a building block for the body’s “master” antioxidant, glutathione. It is an excellent antioxidant in its own right as well—but it does much more than just support redox chemistry.

NAC as an Antioxidant and Anti-Inflammatory

Oxidative damage can certainly trigger immune system activation and therefore chronic inflammation, so I will group these two functions together. Glutathione also offers immune support and cytokine balancing in chronic illness–which directly affects inflammation. Therefore, glutathione precursors are likely to do the same.

Indeed, this study shows that NAC helps to quench inflammation by increasing production of both glutathione, and of enzymes that help produce other antioxidants in the body.

This study shows that NAC also reduces homocysteine—the inflammatory byproduct of an under-effective methylation cycle associated with cardiovascular disease as well as pregnancy and postpartum complications, among many other things.

Excess mucus production is also often a sign of inflammation in the upper respiratory tract. NAC functions as a direct mucolytic, helping to thin secretions and make them easier to expectorate. Because of this, it can protect against worsening of COPD.

NAC for Liver and Gut Support

Glutathione is required for the liver’s six main pathways of Phase 2 Detoxification, and therefore NAC too helps to clear out toxins by acting as its precursor. It also protects the liver from damage and can help to reverse existing Non-Alcoholic Fatty Liver Disease.

Perhaps because of its ability to combat inflammation and support detoxification, NAC also helps to reverse “leaky gut” syndrome. This may also be in part because—similar to its mucolytic properties—NAC can help to break down biofilms, enabling the immune system to access and get rid of chronic intestinal infections.

NAC for Hormonal Support

Oxidative stress is also implicated in a specific type of hypothyroidism—that of poor T4 to T3 conversion (most of which occurs in the gut and liver—see the section above.)

Along those lines, NAC also helps to protect against oxidative damage to ovaries, and helps to support ovulation in women with PCOS as well.

Perhaps also because of its antioxidant function, NAC also helps to improve insulin resistance and therefore obesity.

NAC for Mental/Emotional Support

Surprisingly, even some mental and emotional disorders such as anxiety seem to have inflammation and oxidative stress in the nervous system at their root. Even obsessive and bipolar disorders seem to benefit from NAC.

The Upshot

Most of the benefits of NAC seem to come from its detoxification, antioxidant, and anti-inflammatory support—but the implications of these three functions are huge, and encompass nearly every body system.

While I’m overall a “less is more” kind of a girl in terms of supplementation, I do generally recommend that everyone (or nearly everyone) take at least a multivitamin, an essential fatty acid, and a probiotic. If I had a fourth choice, it would be an antioxidant. Of those, NAC is a great choice. 200-600 mg per day is a good dose, but make sure you take it with food to avoid stomach upset.