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Sodium hydroxide is derived from salt water (brine). It is most commonly manufactured by the electrolysis of brine, a salt (NaCl) solution. During this process the water (H20) is reduced to hydrogen gas (H) and hydroxide ion (OH). The hydroxide ion bonds with the sodium to form sodium hydroxide (NaOH)
Sodium hydroxide (NaOH) is a white, waxy, opaque, odorless crystal consisting of sodium ions and hydroxide ions. It is also known as lye or caustic soda and is used in small amounts in cosmetics and skincare products to establish and hold the pH of a product
Sodium hydroxide was historically used in the formulation of soaps but is also found in a variety of formulas, including bath products, cleansing products, fragrances, foot powders, hair dyes and colors, makeup, nail products, personal cleanliness products, shampoos, shaving products, depilatories, skincare products
Concentrated sodium hydroxide is a strong irritant and corrosive to the skin, eyes, respiratory tract, and gastrointestinal system if ingested. The severity of effects caused by sodium hydroxide is a function of the concentration, the pH, the length of tissue contact time, local conditions and skin type
BUT Sodium hydroxide is approved for use in cosmetics and personal care products in varying concentrations: 5% by weight in nail cuticle solvents, 2% by weight in hair straighteners for general use, 4.5% by weight in hair straighteners for professional use, up to a pH 12.7 in depilatories, and up to pH 11 in other uses as a pH adjuster
In most cases, the sodium hydroxide is not present in the final product. In cases where it is, the pH is usually carefully managed so as to not disrupt the skin
