This shampoo works best on bleached or naturally blond hair, and can be used just like a regular shampoo — lather on a generous amount, give your mane a good scrubbing, rinse thoroughly, and that's it! The color will have a more faded effect after the first use, but will be significantly more vibrant after the second wash.
Psst, this formula is also vegan, cruelty-free, sulfate-free, and formaldehyde-free!
Promising review: "This shampoo is a serious game-changer. I have been bleaching and dyeing my hair pink on and off for years, and it has always faded disappointingly fast. I ended up getting into a routine where I would dye my hair magenta just so it would fade to the pastel pink I wanted — but not anymore! This shampoo allows me to dye my hair a pastel pink and then reapply the color with every shampoo. It comes out bright and beautiful. I used to head to the salon every six to eight weeks, but I can now stretch it out to twelve. Bonus: the shampoo lathers, smells great, and is vegan!" —Mary Colleen
Get it from Amazon for $35 (available in 12 colors).