How can one supplement offer so many potential benefits? Why aren't more people taking this stuff? These are just a few of the questions I couldn't stop asking myself as I revisited the interesting roles N-acetyl cysteine plays in our overall health.

Article ShortcutsWhat Is N-Acetyl Cysteine?What Are the Potential Health Benefits of NAC?Enhances Antioxidant CapacityPromotes Respiratory HealthSupports Immune HealthHelps Cognitive, Neurological, and Behavioral HealthSupports Cardiovascular FunctionImproves Inflammatory ResponsePromotes Liver Health and DetoxificationOther Potential BenefitsHow Much NAC Is Effective?Cautions With NAC SupplementationBottom Line

What Is N-Acetyl Cysteine?

N-acetyl cysteine (or NAC for short) is a precursor to the sulfur-rich amino acid L-cysteine.

L-cysteine is found naturally in many protein- and sulfur-rich foods, such as meat, poultry, egg yolks, broccoli, Brussels sprouts, garlic, oats, onions, and red bell peppers.

L-cysteine is classified as a “conditionally essential” amino acid, which means under certain conditions, we need to consume extra sources because our body cannot make adequate amounts of it from other amino acids.

NAC is not an essential nutrient and it’s not found in nature, so there isn’t an established daily requirement for N-acetyl cysteine.

NAC may be most familiar to physicians since it’s used as a standard treatment for acetaminophen toxicity (overdose of the active ingredient in Tylenol®). NAC is also used medically as an aerosolized mist to break up mucus in the airways of patients with cystic fibrosis.

It’s also a common dietary supplement ingredient that has more functions than simply being a protein building block. Let’s explore.

What Are the Potential Health Benefits of NAC?

Enhances Antioxidant Capacity

N-acetyl cysteine acts on its own as an antioxidant and is also used for the formation of glutathione. The amino acids cysteine, glycine, and glutamic acid combine to form glutathione, the body’s primary antioxidant.

Low glutathione levels can lead to premature aging, excessive free radical production, and difficulty with Phase I detoxification.

Cysteine is the rate-limiting amino acid, meaning if you don’t consume enough of it, you can’t produce enough glutathione.

The liver, lungs, and kidneys produce the most glutathione. Glutathione is built inside our cells with the amino acids mentioned above. It cannot get transferred from the outside of the cell to inside of it, so supplementing with glutathione itself doesn’t seem to work well. Instead, you’re better off taking NAC to support glutathione capacity.

Promotes Respiratory Health

Multiple research studies show NAC has a positive impact on respiratory health.

It’s often recommended as a mucolytic agent, meaning it helps break down mucus in our airways for both acute and chronic conditions that affect breathing.

Both a systematic review and a meta-analysis of clinical trials suggest NAC may be particularly helpful for reducing the frequency and duration of bronchitis symptoms in those with chronic, recurring bronchitis.

Evidence also suggests regular use of NAC seems to improve lung function in those with chronic obstructive pulmonary disease (COPD).

NAC may also help with other inflammation related breathing conditions, such as asthma and nasal sinus infection, and it’s even been shown to have protective effects in smokers.

Supports Immune Health