You've Heard Of Purple Shampoo, But What In The World Is Blue Shampoo For?

Purple shampoos used to be a salon secret for people with dyed blonde hair. But the secret's out, and so are the products. Whether someone is a natural or dyed blond, they can buy their own bottle to get rid of an overly yellow shade that develops over time. 

So what in the world is blue shampoo for? Blue shampoos are a little less well-known but operate in a similar way — except blue shampoo is not for blonds, it's for natural and dyed brunettes to get rid of brassy red undertones. These are also widely available to the public. The way both of these shampoos work is to deposit a small amount of pigment onto your hair, cooling it down. If you look at a color wheel, purple is opposite yellow, blue is opposite orange, and the hues cancel out their opposites. So, here's how you know which of these color-correcting formulas can work for your strands.

When to use purple or blue shampoos

If you've been bleaching your hair blond for any length of time, your stylist has probably introduced you to purple shampoo. Purple shampoos are recommended to remove the yellow tones that develop about a month or so after you color. Blonds, natural or dyed, are more susceptible to the sun's effects because blond hair has less melanin. It doesn't absorb UV rays well, then tends to turn yellow. Purple opposes yellow on the color wheel and cancels it out. It's meant to restore your blond to a more natural hue — unless you're deliberately going full canary. 

Blue shampoo, as another pigmented toning shampoo, is meant for dyed brunettes to calm down the orange hues that can develop due to oxidation, heat styling, or sun exposure. Blue is the opposite of orange in color theory, and using the product neutralizes any dull reddish copper tones. You know you need blue shampoo if you're a dyed brunette and want to restore a cooler tone and remove brassiness.

The best way to use either purple or blue shampoo

Whether you're blond and using purple shampoo between salon visits or brunette and using blue shampoo, make sure to also pick up purple and blue conditioners. Hydration and moisture are super important, especially when you're coloring your hair and heat styling. You want to minimize damage in between salon visits, and one key to maintaining hair health is moisture balance.

Hair industry icon John Frieda has great advice about how to use these products for the most natural results. Regardless of which pigmented shampoo you're using, if your hair is extra yellow or extra brassy, try using these shampoos daily until you get the tone you like. Then alternate with your regular, unpigmented shampoo. 

If you've been off the grid for a while and your hair needs help ASAP, leave your pigmented shampoo on for two to three minutes after you've lathered it into your hair. Go longer if it's extremely brassy. Then, finish with either the blue or purple conditioner. Frieda also says it's OK to use blue shampoo on undyed, natural brunette hair every once in a while to counteract the effects of chlorinated water, sun exposure, or heat styling that bring out unwanted orange tones.