Each potential clogging ingredient has been categorized 0 to 5. 0 meaning the ingredient will not clog your pores. 5 meaning the ingredient is very clogging to your pores. Remember, when skin care products list ingredients on their label they are listed in order of relative amount. That is, the first ingredient listed has the largest amount in the product. The second listed ingredient is what has the second largest amount in the product and so on to the last ingredient listed which has the least amount. Keep in mind if a category 3 ingredient is listed sixth on the label you may not clog from it, but if it is the first or second listed ingredient you may clog up and break out. Use of that product could impede your acne treatment.