If you have oily skin or active acne, alternating between the Lactic and Salicylic peels provides very good results, and is not as harsh as the Salicylic or Glycolic alone. If alternating, apply them 3-4 days apart alternating between the Lactic and Salicylic. The Glycolic acid is also good for oily skin, but as it is the most irritating of the peels I would not recommend starting with it. If you are not achieving the results you desire with our other peels Glycolic should then be used.