Lactic acid is a larger molecule which means it absorbs slower. It’s also a humectant meaning it pulls moisture to itself. This is a great exfoliating acid to use with anybody from normal to dry skin. And as with most acids, it needs to be put on dry skin, or else you neutralize it and make it ineffective. When it comes to the frequency, once a week is best for dry skin. However, those with normal, normal slightly acne skin can use this a little more frequently. As with all acids, you cannot use