As a general rule, sulfate-free shampoos will not have ingredients that end with the word "sulfate" as one of their first-listed ingredients. If you want a sulfate-free shampoo, look for ones that list surfactants such as sodium cocoyl isethonate, sodium lauryl sulfoacetate, cocoyl methyl glucamide sodium cocoyl glycinate, or decyl glucoside as the first few ingredients. It's also worth noting that not all ingredients which end with "sulfate" are cleansers. Behentrimonium methosulfate, for example has conditioning properties and is the primary ingredient in most conditioners.