Olaplex

Olaplex has become a go-to for many colorists as a means of keeping a client's hair in optimum condition during a chemical treatment, which is inevitably destructive. "Sometimes — most of the time when we do crazy colors — the integrity of a client's hair is already badly damaged," says Yoshico-Alexis Ogawa, colorist at Pierre Michel Salon in New York City. "Olaplex not only protects the hair from the process to get a desired color, but it also prevents further damage, makes the hair strong, healthier, shinier, and also helps mend some of the previous damage."

Because of its function, it's considered a bonder, which means it reforms the disulfide bonds that make up the hair, according to colorist Tina Outen. "These bonds are often damaged, fragmented, or shattered when over-bleaching the hair. Using Olaplex essentially means you can bleach your hair far too light and leave that bleach on far longer without it breaking off and leaving it in the sink instead of on your head."