Quest Vitamins LTD,
L-cysteine is a non-essential amino acid and can be made in the body from L-methionine and L-serine. The main feature of L-cysteine is that it is a Sulphur-containing amino acid. L-cysteine contributes to protein structure through the cross-linking that occurs between the sulphur components.
In combination with other nutrients, L-cysteine is a potent antioxidant, protecting cells against the effects of radiation, Smoking and other toxins such as alcohol and heavy metals.
L-cysteine is also necessary for the production of coenzyme A - a vital enzyme in energy production from food. It is additionally a component in the blood sugar-regulating compound, glucose tolerance factor.
Furthermore, L-cysteine is an important structural component of hair. The growth and health of hair depends on an adequate L-cysteine intake.
L-cysteine may be used for:
Although 3-4g daily can be taken without side effects, it is not normally necessary to take more than 1g daily. Over 7g of L-cysteine can lead to the formation of L-cystine Kidney stones. High doses of L-cysteine should ideally be taken with a Vitamin C supplement as this may help to prevent the oxidation of L-cysteine to L-cystine.
Diabetes and Cystinuria:
N.B. L-cysteine should not be confused with L-cystine, which has completely different properties and can be harmful if allowed to build up in the body. L-cystine is the oxidised form of L-cysteine.
1. "The Healing Nutrients Within", E R Braverman & C C Pfeiffer, Keats, 1987.