Ammonium Hydroxide Average pH-adjuster-stabiliser No known benefits Ammonium Hydroxide description Clear, colourless liquid used in cosmetics to adjust a product’s pH. Ammonium hydroxide is synthetic and sometimes used instead of sodium hydroxide to maintain an acidic pH in AHA (alpha hydroxy acid) or similar exfoliant products. The small amounts used in cosmetics are not considered sensitising on skin. Related ingredients: Sodium Hydroxide