Definition for Cysteine
From Biology Forums Dictionary
Cysteine is an amino acid, a building block of proteins that are used throughout the body. When taken as a supplement, it is usually in the form of N-acetyl-L-cysteine (NAC). The body makes this into cysteine and then into glutathione, a powerful antioxidant.
Antioxidants fight free radicals, harmful compounds in the body that damage cell membranes and DNA. Researchers think free radicals play a role in aging as well as the development of a number of health problems, including heart disease and cancer.
NAC can help prevent side effects caused by drug reactions and toxic chemicals, and helps break down mucus in the body. It seems to have benefits in treating some respiratory conditions, such as bronchitis and COPD.