Inflammatory response to sodium lauryl sulfate in aqueous solutions applied to the skin of normal human volunteers.

In this double-blind study, the intensity and duration of the inflammatory response induced by various concentrations of sodium lauryl sulfate (SLS) solution on the forearms of 36 normal male volunteers was dependent upon the concentration and number of applications of SLS. One 24-h application of the 4% or 5% aqueous SLS solution or two successive 24-h applications of the 2% or 3% SLS solutions were sufficient to cause an inflammatory response in the epidermis. Such response makes the skin more permeable for the testing of topical formulations of compounds to document their propensity to irritate.