N-acetylcystine/NAC

OTHER NAMES: NAC,  N-acetyl-cysteine, N-acetylcysteine

PROPERTIES: Anti-inflammatory, antioxidant, expectorant

HISTORY: Our bodies produce cysteine from the foods we eat. Cysteine, in turn, contributes to the body’s production of glutathione. Most of the proposed actions below are actually from the action of glutathione. Besides dietary sources, cysteine can be manufactured synthetically as a supplement.

CONSIDERED USES

Respiratory: NAC is being investigated as a source that reduces the destructive inflammatory process of respiratory illnesses, like flu and COVID-19 (may decrease the incidence of progression. Anti-inflammatory effects may help in chronic lung disease (chronic bronchitis, COPD).

Cardiovascular: Helps decrease blood vessel damage (atherosclerosis), reduces the risk of stroke

Gastrointestinal: Fatty liver disease (non-alcoholic), gallstones may help detoxify the liver and ulcerative colitis.

Genitourinary/Hormone: May enhance fertility, possibly help physical symptoms of PMS, PMDD and menopause

Musculoskeletal: Osteoarthritis. It may help with chronic pain, neuropathic pain, and rheumatoid arthritis.

Neurologic: May slow the neurological progression of Alzheimer’s and Parkinson’s

Skin: Enhances tissue repair, increases skin elasticity/decreases wrinkles, strengthens hair and nails

Mental Health: Decreased stress/anxiety, compulsive-impulsive control like nail biting, trichotillomania, and skin picking. It may help stabilize the glutamate (excitatory neurotransmitter). It is believed to help preserve brain cells. Possibly effective in major depression, schizophrenia, PTSD, bipolar, and OCD (NAC with other prescription mental health medications may lead to better stabilization). Also used with addiction and substance use disorders: Withdrawal from certain substances, including stimulants, cannabis, tobacco, and alcohol, and behaviors like gambling

Glucose: Proposed to help control blood sugar levels

Immunity: Can stimulate or inhibit the immune system, may help autoimmune diseases, decrease symptoms of Sjogren’s, lupus, and rheumatoid arthritis

Cancer: May help lower the risk of cancer

Other: Detoxification of toxins and pollutants (Tylenol overdose treatment in ER), cell repair, possibly anti-aging, and an energy booster help eliminate toxins from the body and may help dissolve blood clots.

What lowers cysteine levels? Type 2 diabetes, nutritional deficits, aging, excessive NSAID (non-steroidal anti-inflammatory) use, stress,  cancer, infections, excessive alcohol, HIV/AIDS, hepatitis, Parkinson’s. Because a decrease in cysteine levels decreases glutathione production,

Side Effects: Skin irritation/rash, fatigue, may lower zinc levels, inhaled products may cause asthma exacerbation, stomach issues, eye irritation, low blood pressure, headaches

Contraindications: Immunosuppressants, antianginals (for episodes of chest pain like nitro and isosorbide)-sometimes used to enhance the effects of nitro, but you need to discuss with your healthcare provider, antifungals

FORMS: Tablets, pills, capsules, IV, inhaled (nebulizer solution), and powders.

Note: N-acetylcysteine reportedly may be safer than L-acetylcysteine

RECOMMENDED BRANDS

• Carlson NAC (500 mg per capsule) (may order from this link on Amazon)

• Doctor's Best® NAC Detox Regulators with Seleno Excell® 600 mg (may order from Amazon link here)

• Life Extension® N-Acetyl-L-Cysteine (600 per vegetarian capsule) (Order from Life Extension Link here)

• NOW® NAC (1,000 mg per tablet) (Order from Amazon link here)

• Seeking Health® NAC (500 mg per vegetarian capsule) (order through Fullscript link here)

Please Note: We only recommend herbal and supplement brands that meet high standards for safety, quality, and transparency. I research each product before sharing. Some links — like those to Amazon or Fullscript— are affiliate links, meaning I may earn a small commission if you buy through them, at no extra cost to you. It helps support my website, Web Guide to Healthcare. Plus, these links often offer discounts for you, fast shipping, and helpful reviews.

DOSAGE: As directed

The following are reported doses and may NOT be supported by evidence (reported by various sources, i.e., WebMD, RxList, Epocrates, ConsumerLabs, German Commission E, NIH publications, and others). Read dosages and instructions carefully when available on the label.

• General: 600-1200 mg by mouth daily. You can divide this amount into lower doses taken 2-3 times daily. Start low and gradually increase as tolerated to the average dose (600-1200 mg daily). The upper limit dose is 3000 mg daily, but you may want to discuss higher doses with a healthcare provider.

• Skin Picking: 1200-1300 mg by mouth daily

Dietary Sources:

If you choose to increase cysteine (and glutathione) by enhancing your diet, cysteine is naturally found in unprocessed meat, fish, seafood, chicken, or turkey. Minor sources are eggs, whole-grain products such as bread and cereals, almonds, and some plants, including broccoli, asparagus, avocados, spinach, garlic, onions, and legumes.

Disclaimer: The material above is for informational purposes only. This information is not intended to diagnose or treat a condition. The uses listed above are tentative; some have or are undergoing research trials, but many are not FDA-approved. It is essential that you investigate these supplements further before deciding to use them. Check interactions and contraindications on sites like Drugs.com or WebMD. Do not attempt to treat a serious condition like liver, kidney problems, high blood pressure, heart disease, cancer, diabetes, or thyroid issues without discussing it with a healthcare provider first. If you are pregnant, do not use supplements without discussing it with your healthcare provider.