Soaps and most cleansers are alkaline and irritate the skin. Because of their alkalinity, soaps partially neutralize the action of Glycolic Acid (AHA). Pro-Derm™ Gentle Cleanser with an optimal acid pH (pH 4.5) is specially formulated to maximize the results of all Pro-Derm™ products. In addition to protecting skin integrity, it is soothing. It gently cleans the skin and completely rinses off with water, leaving no residue behind.