Unlike normal shampoo, we recommend leaving purple shampoo on for up to 3 minutes before rinsing. However, if you're only after a gentle toning, a minute or so should do the job nicely.
In short: No, you shouldn't put purple shampoo on dry hair. While it's true that dry hair will absorb more pigment, it's also uneven in its absorption. For most if not all of us—blonde or not—the ends tend to be drier and more porous than the rest of our hair. Ditto for any areas that were lightened with bleach.
A purple shampoo will not dye your hair but if you leave it on for too long you could find yourself with a little lilac staining. It's easy enough to get rid of – just wash your hair with a clarifying shampoo to reduce the tint!
Too Much of a Good Thing: Purple Shampoo Left On Too Long
You can, in fact, over-tone your hair. Leaving purple shampoo in your hair for an hour or more can cause your hair to look dull and lifeless. To leave purple shampoo for more than 10 minutes is already too much.
There's two reasons why your hair is still brassy after toning or colouring. Either the undertone of the toner/colour is wrong, or the product is too light for you.
Unless you have white hair or gray hair, you shouldn't leave the purple shampoo on for longer than 15 minutes at a time. If you're already leaving the shampoo on for less than 15 minutes and you're noticing a purple tone, then try leaving the product on for even less time.
The short answer: No! People have been trying this technique because your hair will absorb more of the purple pigment when it's dry.
It's thought that by applying pigment to dry strands (which are more absorbent), the end result will be more vivid. This might be the case for some people, but there's also the risk of more porous, damaged sections of the hair (the ends) absorbing more pigment than the newer hair towards the root.
The purple shampoo can cause build up making the hair look dull and darker if overused." This makes the lightening process more difficult to create a seamless blend.
Zoe's answer: Leaving purple shampoo in your hair for longer than the recommended time is not always a good idea. The longer you leave it, the more pigments will be deposited on your hair and they could even stain it permanently.
Purple shampoo should be applied in the shower or during a hair wash. While your hair is wet, apply the shampoo and lather it onto your hair. The amount of shampoo that you use will vary depending on your choice of product and how brassy your hair is looking.
There's an internet rumour that dry hair absorbs purple shampoo better, resulting in enhanced toning. However, while dry hair is more porous, it can't absorb the shampoo evenly. In short, applying purple shampoo to dry tresses will lead to a patchy hair nightmare.
Start by leaving it on for 2-3 minutes:
Depending your level of brassiness, 2-3 minutes should be enough time for the shampoo to do its work. After the time has passed, rinse thoroughly with cool water.
Purple shampoo only works on light-colored hair, so anything from an ashy blonde, to grey/white hair.
The reason purple shampoo works is that purple is opposite yellow on the color wheel, so the purple pigments in the shampoo cancel out the yellow tones, leaving hair looking brighter and cooler in tone.
It's important to note that the pigment in purple shampoo isn't a lightener or hair dye but a gentle toner that works overtime. So it can't darken your hair or make it any lighter. For this reason, if your hair tone is too dark, it won't make it any brighter.
Is purple shampoo a toner? Any product that dispenses pigment to adjust hair tone can be considered a toner, and that includes purple shampoo. Its pigments work to neutralize brass.
Others may be too weak, meaning they need 10 minutes or more to make a noticeable difference to brassy tones if they manage to do anything at all. However, we've created the 'Goldilocks' of purple shampoos; a product with just the right level of purple tones, which takes 3-5 minutes to work its magic on brassy strands.
Purple shampoo is for already bleached hair, so if you're hoping to lighten brown hair with purple shampoo, you'll be disappointed. This is all down to the fact that purple shampoo isn't lightening. Instead, it brightens blondes by canceling out yellow tones, which just happen to be opposite purple on the color wheel.
Yes, purple shampoo could be making your blonde hair look darker — but don't worry, it's fixable.
Alternate your purple shampoo use with regular shampoo formulated for color-treated hair so your hair color stays light and even. If you have warmer naturally blonde hair, use purple shampoo only when you notice yellowing.
Keep in mind that purple shampoo does not replace your regular shampoo and should only be used once or twice a week. Doss warns that there is such a thing as too much purple. “When you eliminate too much yellow, it visually ends up darker and a lot of people don't want it to look darker,” she says.
Purple counteracts yellow, blue counteracts orange. They are opposites on the color wheel, so that's why. So if your hair has an orangey hue, the reality is, purple shampoo won't work.