Sodium lactate is the sodium salt of lactic acid and is one of the hydrating substances that are produced by the skin to preserve the moisture and physiological pH. Sodium lactate is used not only in cosmetics but also in the food industry as a humectant and an acid regulator. On the skin, the growth of foreign microorganisms is inhibited by maintaining the skin's natural acid barrier. In addition, sodium lactate is a well-tolerated form of hydration that also keeps emulsions chemically stable.
see. Heike Käser 2010 "Natural Cosmetic Raw Materials", Linz, Freya Verlag, 3rd Edition 2012