Grandma's Cysteine & Cystine Guide
Both Nonessential Acids

Cysteine is very unstable and is easily converted to L-cystine, however, each form is capable of converting into the other as needed. These two amino acids are closely related, each molecule of cystine consists of two molecules of cysteine joined together. Both are sulfur-containing amino acids that aid in the formation of skin and are important in detoxification.

Cysteine is present in alpha-keratin, the chief protein constituent of the fingernails, toenails, skin and hair. Cysteine aids in the production of collagen and promotes the proper elasticity and texture of the skin. It is also found in a variety of other proteins in the body, including several of the digestive enzymes.

Cysteine helps to detoxify harmful toxins and protect the body from radiation damage. It is one of the best free radical destroyers, and works best when taken with selenium and vitamin E . Cysteine is also precursor to glutathione , a substance that detoxifies the liver by binding with potentially harmful substances there. It helps to protect the liver and brain from damage due to alcohol, drugs, and toxic compounds in cigarette smoke. Since cysteine is more soluble than cystine, it is used more readily in the body and is usually best for treating most illnesses. This amino acid is formed from > L-methionine Vitamin B6 is necessary for cystein synthesis, which may not take place as it should in the presence of chronic disease. Therefore, people with chronic illnesses may need high than normal doses of cysteine, as much as 1,000 milligrams three times daily for a month at a time.

Supplementation with L-Cysteine

Supplementation with L-cysteine is recommended in the treatment of rheumatoid arthritis, hardening of the arteries, and mutogenic, disorders such as cancer. It promotes healing after surgery and severe burns, chelates heavy metals, and binds with soluble iron, aiding in iron absorption.

This amino acid also promotes the burning of fat and the building of muscle. Because of its ability to break down mucus in the respiratory tract, L-cysteine is often beneficial in the treatment of bronchitis, emphysema, and tuberculosis. It promotes healing from respiratory disorders and plays an important role in the activity of white blood cells, which fight disease.

Cystine r the N-acetylcysteine aids in preventing side effects from chemotherapy and radiation therapy. Because it increases glutathione levels in the lungs, kidneys, liver, and bone marrow, it has an anti-ageing effect on the body, reducing the accumulation of age spots, levels than supplements of cystine or even of glutathione itself.

Caution: People who have diabetes should be cautious about taking supplemental cysteine because it is capable of inactivating insulin. Persons with cystinuria, a rare genetic condition that leads to the formation of cystine kidney stones, should not take this supplemental amino acid.


The statements made here have not been approved by the Food and Drug Administration. These statements are not intended to diagnose, treat or cure or prevent any disease. This notice is required by the Federal Food, Drug and Cosmetic Act.


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