If you’re a blonde, brunette, or redhead in need of toning your locks, purple shampoo might be just what you need. Not only will it make your hair look shinier and brighter than ever, but it’ll also make sure your color stays true while keeping your hair healthy. So when should you reach for this magical product? Let’s take a look.

Purple shampoo is great for getting rid of unwanted brassiness and keeping any kind of color-treated hair looking bright and vibrant. If you have blonde hair—whether natural or dyed—that yellowish tint that can come with age or exposure to sun and heat can really knock the shine out of your ‘do. The purple shampoo helps bring back that shine by neutralizing the yellow tones. This same trick works to keep red hair looking its best too!

If you have darker hair that’s been lightened or highlighted, purple shampoo is a must-have if you want those highlights to stay bright and not turn an orangey-brassy color. Be sure to use purple shampoo no more than once a week though—any more often than that could leave your locks feeling dry and brittle.

Finally, if you don’t have any kind of color-treated hair but still want shinier locks, give purple shampoo a try! But again, go easy on it—only use it once or twice a week as overuse can cause drying on any type of hair. (See our article on how to use purple shampoo.)

Whether you’re trying to protect your natural blonde locks from turning brassy or keeping highlights looking their best, purple shampoo is an effective way to do so without causing undue damage to the health of your hair. Check out our top picks of purple shampoos to keep your colored tresses looking their best!