Sodium Metabisulfite

Sodium Metabisulfite is an inorganic salt used as a disinfectant and preservative agent in cosmetics and personal care products, according to Wikipedia. It is also considered a reducing agent that donates hydrogen molecules to other substances in cosmetics and personal care products. This ingredient can sometimes function as an antioxidant, preventing or slowing deterioration of formulas caused by chemical reactions with oxygen. Sodium Metabisulfite is seen as an ingredient primarily in hair care products, such as formulas for permanent waves, hair bleaches, hair dyes, colors and tints, and also in some bath and skincare products

WATER SOLUBLE WITH USAGE RATE OF 0.001-0.2%