How long do you leave hair dye in

By: | Last Updated: February 11, 2022

Changing up your hair color once in a while can be refreshing, and doing it by yourself can even be therapeutic. 

But whether you’re a hair dyeing fanatic or a newbie, it’s always best to learn proper techniques to dye your hair safely.

In this article, we’re going to tackle how long to leave hair dye in your hair, whether it’s a permanent or semi-permanent dye. 

I know it can sometimes get confusing, especially if it’s your first time, but we’ll break down the basics so you can get that vibrant hair color you’ve been dreaming of.    

How long to leave hair dye on roots?

Whether you’re touching up your roots or doing an all-over color, the hair on your roots processes differently compared to the rest of your hair.

That’s because the hair on your roots is healthier compared to the mid-length and ends of your hair since it hasn’t been exposed to UV, heat, or chemicals as much as the rest of your hair.

So it’s recommended to leave the hair dye in for a few extra minutes as it takes the hair dye longer to penetrate your hair shaft. 

If the label on the box says to leave it on for 20 minutes, add an extra 10 minutes. 

Also, if you’re doing an all-over color, make sure to apply hair dye on your roots last to avoid hot roots, as the heat from your head will make the dyeing process faster. 

How long to leave hair dye on roots

How long to leave permanent hair dye in?

If you’re ready for the commitment that permanent hair dye comes, the amount of time you leave it in can determine the color you’ll get. 

Can I leave hair dye for 10 minutes?

Hair dyes consist of hydrogen peroxide and ammonia. Hydrogen peroxide opens up the hair shaft, while ammonia deposits color pigments into your hair fiber. This process usually takes about 15-20 minutes to work properly.

So if you leave hair dye in for just 10 minutes, the chemicals don’t have enough time to penetrate your hair, resulting in no changes in your hair color. 

How long should you leave hair dye in before washing it?

For most box hair dyes, the standard time to leave them in your hair is 30 minutes and should not exceed 45 minutes. The dye stops developing after 45 minutes and starts causing damage to your hair instead.

It takes 15 minutes for the peroxide to open your hair shaft, while the remaining 15-30 minutes is for the color to deposit in your hair. 

So it’s best to follow the instructions on the label of the hair dye you’re using.

Since everybody’s hair is different, there are also factors to include on how long to leave the dye in your hair:

  • Hair thickness – how fine or coarse your hair is can also play a role in the time for your hair to absorb the dye. If you have fine hair, keep an eye on how fast it processes as it absorbs dye faster compared to coarse hair. 
  • Hair porosity – the porosity of your hair depends on how much moisture it absorbs. So if you have porous hair, make sure not to leave the dye in your hair longer than the recommended time to avoid damaging your hair.

CHECK OUT: How To Fix Patchy Hair Dye

How long to leave semi-permanent hair dye in?

If you’re not ready for a permanent hair color change or just want a temporary bright hair color, then semi-permanent hair dye is an excellent alternative. It’s also less damaging to the hair because it doesn’t contain peroxide. 

But how long should you leave it on your hair? Well, it depends on the brand you’re using. Here’s a quick guide to how long to leave semi-permanent hair dye from 5 popular brands: 

How long do you leave Splat hair dye in? 

Splat hair dye has a wide range of semi-permanent colors to choose from. How much time you leave it in your hair depends on how dark you want the colors to show. But generally, 20-40 minutes will do.

Here’s a quick time guide on how long you should leave it in based on the colors you pick:

  • Light or pastel colors – including pink, light blue, green, yellow, or gray. If you only want to add pastel colors into your hair, leave it in for 20 minutes.
  • Medium colors – including red, blue, yellow, green, purple, or orange. If you want a more intense color, leave it on for 25 minutes.
  • Dark colors – purple, Fuschia, chewing gum pink, turquoise, aqua, or blue. For a darker or intense color, wait for 30-35 minutes before washing.
Temporary purple hair dye for dark hair

How long do you leave Unicorn Hair Dye in?

Lime Crime has a vibrant semi-permanent hair dye line called Unicorn Hair Dye that isn’t damaging to the hair.

The hair dyes can be left on your hair, depending on how thick your hair is. If you have thick hair, you can leave the dye in for 45 minutes; if you have thin hair, leave it in less time.

Leave it on for 1-2 hours if you want a more intense and longer-lasting color.  

How long do you leave Arctic Fox hair dye in?

This vegan and cruelty-free brand has been specializing in semi-permanent hair dyes for a while now, so they really know what they’re doing.

According to their official website, Arctic Fox hair dyes can be left in your hair for a minimum of 30 minutes, depending on how intense the color you want it to be.

Their hair dyes also contain conditioners, so you don’t have to worry about damaging your hair even if you leave it in for a few more minutes or even hours!

How long do you leave Manic Panic hair dye in?

With over 40 shades to choose from, Manic Panic is also a leading brand for bright semi-permanent hair dyes. 

According to their official website, you can leave Manic Panic hair dyes in for a minimum of 30 minutes to an hour or more.

But since we got your back, here’s a quick cheat sheet:

  • If you have a bottle of intense color but only want a lighter or pastel color, leave it in for 15-20 minutes.
  • If you have a bottle of pastel color but want a more intense color, wait for 30-40 minutes.
  • But remember, this trick doesn’t work on all shades. If you have a bottle of light pastel colors like Blue Angel, Blue Steel, Amethyst Ashes, or Virgin Snow, these colors won’t turn darker even if you leave them in longer.

How long do you leave Punky Colour hair dye in? 

Punky Colour is a UK-based hair dye company that has a variety of semi-permanent hair colors.

It’s easy to apply, and you can leave it in your hair for 15-30 minutes, depending on how intense you want the color to be.

CHECK OUT: Does hair dye expire?

Does hair dye get darker the longer you leave it in?

Now that we know the recommended time hair dye needs to process in your hair, what happens if you leave hair dye longer? Well, it depends on what type of dye you’re using.


Semi-permanent hair dye is less damaging to your hair since it doesn’t contain any developer. It’s only designed to deposit color pigments on the external structure of your hair without lightening it. 

As mentioned above, you can leave semi-permanent hair dye in for 30 minutes or longer if you want a darker color. You can play around with different colors without worrying about hair damage. 

But if you don’t like the shade that it comes out, don’t worry; semi-permanent hair dye eventually washes out. 

mixing hair dye developer – Curling Diva


Since permanent hair dye consists of harsh chemicals like ammonia and peroxide, leaving it on for more than 45 minutes can turn your hair dry and brittle. 

Generally, hair dyes stop developing after 45 minutes, but if you’re using black hair dye, it might come out darker than you expect and will look obvious because of how dark it is.

If you’re trying to lighten your hair for one or two levels, leaving the dye on longer can result in lighter strands because of the peroxide.

CHECK OUT: How long does henna hair dye last

Final Thoughts

Changing your hair color is always a fun project, but it also has its downsides if you don’t have the proper techniques. Always do your research or ask a trusted hairstylist before dyeing your own hair.

How long you leave hair dye in your hair depends on what type of dye you’re using. If you’re using permanent hair dye, 30-45 minutes is a good baseline. 

But if you’re using a semi-permanent one, you can go from a minimum of 30 minutes to even several hours!  

That’s the beauty of hair dyes. As long as you’re having fun, paint as much as your heart desires. Just make sure to take good care of your hair to avoid damaging it.

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