I am pleasantly surprised by the ease of use. For several years I regularly go to the dermatologist and let (acne) fruit acid peels due to my bad skin perform. It works every time very good, is also very into the money. With the 5% fruit acid started first. A slight tingling sensation could be felt on the skin as well as I know it from the treatment my doctor. The effect effect the next day, however, was very low, but it is also in the instructions that between 5-8% are recommended for acne treatment and I know that my doctor used a higher dose. More than 5% but I am alone at home not dare. I will now increase and hopefully soon find that a higher dose of my skin feels good. If it works, it is definitely worth the money. Addendum: I'm after eingen weeks now progressed to 40% and can still confirm that it works. Please Note: always have enough neutralizer at hand and see if there is enough before doing the treatment.