Cleansing Agent, Sensitizing, Ph Adjusters

Average
SODIUM HYDROXIDE

Also known as lye, sodium hydroxide is a highly alkaline ingredient used in small amounts in cosmetics to establish and hold the pH of a product.

ItŠ—Ès also used as a cleansing and denaturing agent. In high concentrations, itŠ—Ès a significant skin sensitizer.

References for this information:

Acta dermato-venereologica, March 1995, pages 97-101

http://www.cosmeticsinfo.org/ingredient/sodium-hydroxide