N-acetyl-cysteine (NAC)

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Other names for n-acetyl-cysteine (NAC)

NAC
Acetylcysteine
N-Acetyl Cysteine

Synopsis of n-acetyl-cysteine (NAC)

N-Acetyl-Cysteine (NAC) is a stable, acetylated form of the amino acid L-cysteine, used both as a pharmaceutical agent and dietary supplement. It serves as a precursor to glutathione, one of the body’s most powerful endogenous antioxidants, and plays a critical role in detoxification, immune function, and the neutralization of oxidative stress.

NAC is commonly used in clinical settings to treat acetaminophen (paracetamol) overdose, where it replenishes depleted glutathione levels in the liver and prevents potentially fatal hepatotoxicity. It is administered intravenously or orally in emergency medicine for this purpose. Beyond its detoxifying effects, NAC has mucolytic properties—meaning it breaks down mucus—making it a well-established treatment for chronic bronchitis, COPD, asthma, and cystic fibrosis, where it helps reduce the viscosity of mucus in the lungs and improves breathing.

In integrative and preventive medicine, NAC is used as a supplement for a variety of conditions tied to inflammation, oxidative stress, and impaired detoxification. It has shown benefit in polycystic ovary syndrome (PCOS), mental health disorders (notably OCD, bipolar disorder, and schizophrenia), and neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease, thanks to its antioxidant and neuroprotective activity. It may also support immune function, reduce the frequency and severity of respiratory infections, and assist in the treatment of substance use disorders, particularly in reducing cravings and withdrawal symptoms.

Supplemental NAC is usually taken orally in capsule or powder form, with dosages typically ranging from 600 to 1,800 mg per day, depending on the condition being addressed. It is considered generally safe but can occasionally cause gastrointestinal upset or interact with certain medications.

Historical Use
NAC does not have a traditional or herbal medicine background, as it is a synthetic derivative of a naturally occurring amino acid. Its medical use emerged in the mid-20th century, primarily in Europe, when its mucolytic properties were identified and applied to respiratory illnesses. By the 1970s, it had become standard treatment for acetaminophen poisoning, and this lifesaving role remains its most well-documented and FDA-approved indication.

Although NAC itself is relatively modern, its physiological precursor—cysteine—can be found in high-protein foods and in some traditional broths or remedies that were likely rich in cysteine-containing compounds. These foods and tonics may have inadvertently supported glutathione production and detoxification in the body, but this was not understood at the time.

In contemporary times, NAC has been explored in functional and orthomolecular medicine, where practitioners emphasize its ability to restore antioxidant balance, modulate inflammation, and aid in detoxification pathways—particularly in patients exposed to environmental toxins, heavy metals, or experiencing high oxidative stress from chronic illness.

Due to growing interest in its therapeutic potential, NAC gained significant popularity as an over-the-counter supplement, although in some countries (including temporarily in the U.S.), regulatory attention has been drawn due to its overlap with pharmaceutical applications.

N-acetyl-cysteine (NAC) is used for these health conditions

Addictions (drugs) (Scientific)
Addictions (general remedies for) (Scientific)
Addictions (sugar or refined carbohydrates) (Scientific)
Addictions (tobacco smoking or chewing) (Scientific)
Alcoholism (Scientific)
Alzheimer's Disease (Scientific)
Anxiety (Scientific)
Anxiety Disorders (Scientific)
Arthritis (Scientific)
Asthma (Scientific)
Autoimmune Disorders (Scientific)
Bipolar Mood Disorder (Scientific)
Cancer Treatment (reducing side effects) (Scientific)
Cardiovascular Disease (Scientific)
Chemotherapy (reducing side effects) (Scientific)
Chronic Obstructive Pulmonary Disorder (Scientific)
Cirrhosis of the Liver (Scientific)
Colitis (Scientific)
Congestion (bronchial) (Scientific)
Congestive Heart Failure (Scientific)
Crohn's Disease (Scientific)
Depression (Scientific)
Diabetes (Scientific)
Emphysema (Scientific)
Environmental Pollution (Scientific)
Fibromyalgia Syndrome (Scientific)
Fibrosis (Scientific)
Free Radical Damage (Scientific)
Gastritis (Scientific)
Heavy Metal Poisoning (Scientific)
Hepatitis (Scientific)
Infection (Scientific)
Infection (bacterial) (Scientific)
Inflammation (Scientific)
Inflammatory Bowel Disorders (Scientific)
Parkinson's Disease (Scientific)
Peripheral Neuropathy (Scientific)
Schizophrenia (Scientific)

n-acetyl-cysteine (NAC) is used to support these body systems

Brain (Scientific)
Bronchials (Scientific)
Gastrointestinal Tract (Scientific)
Heart (Scientific)
Hepatic System (Scientific)
Immune System (Scientific)
Intestinal System (Scientific)
Liver (Scientific)
Lungs (Scientific)
Mucus Membranes (Scientific)
Respiratory System (Scientific)