Hypochlorous Acid: Considerations for Use in Skin Care and Skin Preparation.

Hypochlorous acid (HOCl) is endogenously produced by neutrophils, macrophages, and other cells of the innate immune system and acts as a natural antiseptic. The active components are chlorine and reactive oxygen species in the form of a weak acid. It can be manufactured by electrolysis or chemical acidification of sodium or calcium hypochlorite, producing a mixed solution of HOCl and hypochlorite ions (OCl-) in equilibrium. The ratios of HOCl to OCl- within the solutions vary depending upon the manufacturing process and method used for stabilization. These ratios can change over time, and maintaining pH and storage conditions is essential to ensure a long shelf life. Hypochlorous acid solution has become favorable as an alternative skin preparation and skin care in aesthetics and dermatology. This review will examine the manufacture, toxicity, and efficacy of HOCl used in skin preparation and other areas of use in health care.