Phosphates are chemical compounds that help to thicken and stabilize liquid shampoos - ingredients like Distarch Phosphate or Hydroxypropyl Starch Phosphate. They can dry out your scalp and hair, which is a concern if you're dealing with dry hair, damaged hair, or brittle hair. For color-treated hair or keratin treatments, phosphates strip results faster. Environmentally, they wash into waterways and trigger algal blooms that kill aquatic life. The good news is that you don't need them for effective cleaning.