Redken Chemistry System is a professional use treatment collection that adds shine and strength, seals the hair cuticle, and adds a brilliant gloss that lasts for at least three weeks! The Chemistry System is an "inside-out approach" to creating healthy, shiny hair. These professional-use only treatments offer intense, customized benefits for individual hair needs. In about 5 minutes, you can improve the quality of your hair. These advanced formula treatments provide immediate results after just one treatment.