Cosmetic Conundrums with Zoe Diana Draelos, M.D.

Q. What is a 2-in-1 shampoo?A. Two-in-1 shampoo is a shampoo designed to cleanse and condition in one step. The original 2-in-1 shampoos neither conditioned well nor cleansed well, but the new varieties have taken advantage of modern silicone technology.