Dear Paula,
I truly appreciate all your work. You have saved me so much time, effort, and money. I am 26 years old and trying to both improve and maintain my skin. For the most part, I am well-versed in skin care; however, due to my age, I am not sure how much or how often I should use glycolic acid products, retinol products, or other exfoliant-type creams. Currently, I am using the ReSurface (retinol) cream by Lancome in addition to a Cetaphil moisturizer. Is it okay to use this cream on a daily basis, or, because of my age, should I limit the use of this product to a few days a week or not at all? Do I wait until I actually have wrinkles to use these types of products? I use a protective sunscreen on a daily basis, thanks to your advice.

Lesley, via email

Dear Lesley,
Great questions, and the answers are relatively simple. First, retinol (the entire vitamin A molecule) is not an exfoliant. Rather, when retinol is absorbed into the skin it converts to all-trans-retinoic acid, which is a cell-communicating ingredient that, via receptor sites, can tell a skin cell to make normal-functioning cells. Glycolic acid (an alpha hydroxy acid) is indeed a topical exfoliant that removes thickened layers of built-up, sun-damaged, dead skin cells that cannot be shed in a healthy manner on their own. Combining retinol (or any cell-communicating ingredient) with a well-formulated glycolic acid product does not overdo anything, because they actually work synergistically to help skin look its best.

Cell-communicating ingredients—along with antioxidants, anti-irritants, and ingredients that mimic the structure of skin—can and should be present in most of the skin-care products you use, and you should use such products at least twice a day. Glycolic acid or any other topical exfoliant, such as beta hydroxy acid (salicylic acid), can be used as often as needed or tolerated. But be cautious of overdoing it or using multiple exfoliants at any given time. For most people, once-a-day use of an AHA or BHA product is sufficient, while for others an application schedule of every other day or every two or three days works best. You need to judge how your skin is feeling and looking to determine what works for you.

Source: Paula Begoun