Irritancy of low concentrations of soap and synthetic detergents as measured by skin water loss.

The irritancy of low concentrations of commercially available soaps and detergents (surfactants) in bar form was determined by means of measurements of water loss of the skin. The percentage of increase of vapor (water) loss after application of the soap solutions was taken as a measure of skin irritancy. The tests were performed in 19 human volunteers with 1% solutions of Sporex, Devela, Lux, Lactacyd and Aveenoderm. Devela and Lactacyd were found to provoke marked effects, Lux was less harmful whereas Sporex and Aveenoderm did not lead to a considerable increase of skin vapor loss. Longitudinal studies showed that the irritant properties of soap solutions are additive. The results suggest that the influences of the pH of a soap solution on the skin-damaging effort is less important than assumed thus far.