We have been using Mayerling Skin Renewal System since 2003. The products are easy to use and we have never had a client complain about the results of their treatment. The glycolic acid can even be used in summer. We have had tremendous success with acne and sun damaged skin. With the retail products, we have had fantastic feedback especially with the Mayerling Forte Creams / Lotion and Eye Cream. If you are looking for a product that works, and is easy to use then I would highly recommend Mayerling Skin Renewal System. As well as being a fantastic product it is also cost effective.