This has come up in several conversations over the past week and I thought I'd take a moment to address it here.
Individuals are asking the question: do sulfate-free cleansers automatically clarify?
I need to make it clear that “sulfate-free” does not necessarily mean "surfactant-free." A surfactant—sometimes referred to as a detergent—is a substance that, when dissolved in water, gives a product the ability to remove dirt from surfaces such as the human skin, textiles, and other solids. There are several different types of surfactants, ranging from harsh to mild.
For example, many non-sulfate based cleansers contain an ingredient called “cocamidopropyl betaine,” which is a surfactant just as sulfates are. However, cocamidopropyl betaine is derived from coconut oil and is therefore not considered harsh like sulfates; however, it will clarify and remove product build-up because it is still a surfactant. Clarifying is largely necessary for those who still use non-water soluble silicones in their conditioners and styling products.
Conclusion: if your cleanser is sulfate-free, but contains another surfactant which is milder, such as cocamidopropyl betaine, you will receive the benefits of clarifying without the harsh effects of sulfates.