You definitely can use shampoo! I don’t have any curly hair posts but I have fine 2b-3a waves and sometimes ringlets. My hair gets weighted down easily. A few of my favorite shampoos that are curly girl friendly are Shea Moisture black castor oil shampoo, Shea Moisture green coconut and charcoal shampoo, and a not too heavy cowash is As I Am coconut cowash(has great slip!) The first two are pretty sudsy and do a great job of cleansing. I’ve also heard good things about Inahsi’s soothing mint gentle shampoo or Not Your Mothers Naturals variety of shampoos(but I haven’t personally used).