Sodium Laureth Sulfate is a mild surfactant and hence, is not as harsh as Sodium Lauryl Sulfate. However, it is rarely used on its own as it does not produce a very good lather and is also incapable of removing dirt as effectively as Sodium Lauryl Sulfate. This is the reason why most manufacturers go for Sodium Lauryl Sulfate, which is stronger, cheaper and more effective. There are rumors about Sodium Lauryl Sulfate being carcinogenic, however there is no truth in that.