(also referred to as...)
Dicysteine, L-Cysteine, L-Cystine, N-acetylcysteine, NAC
2-Amino-3-Mercaptopropionic Acid and 3,3-Dithiobis(2-Aminopropionic Acid)
Description
Cysteine and cystine are closely related. One cystine molecule is composed of two bonded cysteine molecules and each can convert to the other as required. Both amino acids contain sulfur (via free sulfhydryl groups) which makes them powerful antioxidants.
The acetylated form of cysteine is N-acetylcysteine (NAC) and contains a bonded acetyl group. In this form, NAC is more easily absorbed, more stable, and safer to use than cysteine on its own, which can be neurotoxic in very high doses.
NAC is effective at promoting glutathione synthesis. This amino acid "combo" incorporates cysteine, glutamic acid, and glycine and has powerful antioxidant and immune stimulating properties. Some studies have shown that supplementing with NAC yields higher glutathione levels than supplementing with cysteine or glutathione directly.
Cysteine is found in alpha-keratin, the main protein of fingernails, toenails, skin, and hair.
Ailments / Situations Where Used
Cysteine and cystine can be used to help prevent or treat alcoholism, heart disease, liver disease (cirrhosis, hepatitis, etc.), Wilson's disease (copper toxicity), and bronchopulmonary diseases such as asthma, chronic bronchitis, cystic fibrosis, pneumonia, and sinusitis. Cysteine also aids collagen production and facilitates proper skin elasticity and texture.
Cysteine, cystine, and NAC possess powerful antioxidant properties and work best when taken in combination with selenium and vitamin E. They promote liver detoxification by binding toxins and heavy metals such as mercury and lead and facilitating their removal from the body. These amino acids also reduce free radical damage and, in combination with their "liver repair" services, are ideal in treating substance abuse.
NAC can help prevent side effects associated with chemotherapy and radiation therapy. It may also prevent cancer by reducing the number of chemical adducts that cancer-causing compounds use to attach to DNA and cause damage. As mentioned above, the antioxidant properties of these amino acids helps reduce free radical damage, often associated with DNA mutation and cancer development.
NAC's mucolytic (mucus thinning) properties help remedy chronic bronchitis and other respiratory disorders. Its "sulfur stores" break down the disulfide bonds that make mucus thick.
NAC supplementation increases glutathione levels, particularly in the lungs, kidneys, liver, and bone marrow, resulting in an anti-aging effect. AIDS patients can also benefit from NAC supplementation via increased immune-building glutathione levels. When dealing with the common cold, some studies show success with NAC supplementation -- symptoms were reduced and the duration of infection decreased.
Source
Good sources of cysteine/cystine include broccoli, Brussels sprouts, egg yolks, garlic, oats, onions, poultry, red peppers, wheat germ, and yogurt.
L-cysteine and L-cystine are available in a multi-amino acid, in addition to protein powder supplements.
NAC is available in isolated form in various doses.
Optimal Absorption
Cysteine is more soluble than cystine, with L-cysteine being the most absorbable form. If supplementing, take 500mg three times daily. This dosage can go as high as 1,000mg three times daily for one month at a time. NOTE: High levels of L-cysteine supplementation should be for acute situations only and you must be under the supervision of your naturopath or other health practitioner.
NAC supplementation is considered extremely safe. Dosage can range from 500 to 1,200mg daily, with 600mg being a typical dosage.
Vitamin E and selenium work well with cysteine's antioxidant actions. Vitamin B6 is necessary for cysteine synthesis. Ensure your intake is adequate and supplement as required.
Contraindications / Precautions / Warnings
It is not recommended to take a single amino acid for an extended period of time without supplementing with other amino acids as well. Long-term isolated amino acid supplementation can create an imbalance in the body.
Diabetics should take caution when supplementing with cysteine, as it can interfere with and inactivate insulin.
Do not supplement with cysteine if you are susceptible to cystine kidney stones.
NAC capsules have a strong smell, but generally do not cause bad breath or stomach upset.
Ailment / Situation Listing
