Cysteine is a sulfur-containing amino acid found in foods like poultry, eggs, dairy, red peppers, garlic and onions. It works as an antioxidant, in the production of collagen (a component of hair, skin and nails) and is also used in the body to create glutathione, another important antioxidant.
L-Cysteine is a non-essential standard amino acid that can be synthesized by the human body under normal physiological conditions if a sufficient quantity of methionine is available.
L-Cysteine is commonly used as a precursor in the food and pharmaceutical industries.
In the cosmetics industry, it can be used for hair perming formulations.