A method to assess perspiration reduction of a composition comprising obtaining an amount of water in stratum corneum in a first area of skin on an individual using confocal Raman spectroscopy, applying a composition to the first area of skin on the individual, having the individual perform an activity to cause the individual to perspire, and obtaining an amount of water in stratum corneum in the first area of skin on the individual after the activity using confocal Raman spectroscopy.