L-cysteine

Description

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.

Functions

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 a major part of the peptide gluthathione, which in turn is a component of the antioxidant enzyme, gluthathione peroxidase.

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.

Supplemental Uses

L-cysteine may be used for:

Bronchial conditions (L-cysteine helps to liquefy and clear mucus from the lungs and bronchial tubes (1).
Radiation protection - especially in the context of medical treatments (1).
Protection against side effects of chemotherapy treatment (1).
High cobalt and Molybdenum levels (L-cysteine and/or L-methionine) have been shown to alleviate the symptoms of excessive levels of these metals and may also be useful in other cases of heavy metal toxicity (1).
Hair loss and poor hair growth (1).

Safety

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.

INTERACTIONS AND CONTRA-INDICATION

Diabetes and Cystinuria
L-cysteine should be avoided by diabetics. People with the hereditary disorder cystinuria (in which large amounts of L-cystine and other Amino Acids are excreted in the urine), should also avoid L-cysteine supplements.

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.

References

1. "The Healing Nutrients Within", E R Braverman & C C Pfeiffer, Keats, 1987.