What Happens If You Leave Hair Dye In Too Long?

Home hair dyeing is a great solution, isn’t it? Cheaper than a salon, it can lead to great results if you do it properly. But what happens if you leave hair dye in too long? Will it affect the colour? Is it bad for your hair? Let’s have a look into the answers to these questions!

Does leaving hair dye in longer make it last longer?

Does leaving hair dye in longer make it last longer

You may be after a rich, vibrant colour, and are going for a home dyeing kit. If you leave it on longer than the recommended time, surely this will improve the colour?

Well, not necessarily.

The times for leaving dye in exist for a reason, and that reason is that some of the chemicals used in permanent hair dyes are very strong.

  • 30 minutes is plenty enough time to let the dye sit, as this is long enough for the chemicals to develop and permeate the hair shaft.
  • Leaving the dye any longer can seriously damage your hair, and may leave it feeling dry, brittle and damaged.
  • If you exceed the recommended time, you won’t necessarily get a longer lasting colour, but you do run the risk of turning your hair into straw.

Using a semi permanent hair dye can benefit not only your colour but your hair, as these dyes don’t contain so many harsh chemicals.

  • They only last 6-12 washes, but they can give your hair a great colour – and they will be less likely to damage it.
  • You can leave a semi permanent dye on for extended periods; you can even wrap your hair in a towel and sleep on it!

If you want to improve your final colour, whether with permanent or semi permanent dyes, here are a few tips you can try:

  1. Rinse your hair in cool water. Hot water lifts colour more quickly, so rinsing in cold water – although it may make you shiver – is better for the colour.
  2. Soak your hair in white vinegar. After you have dyed and rinsed your hair, soak the entire head in white vinegar. This will raise the pH of your hair and allow the colour to set better.
  3. Wait as long as possible between shampooing. Although you will want to wash your hair when it needs it, shampooing can strip out the colour faster.
  4. Deep condition your hair. Improving the quality of your hair will help the dye set better, so don’t skimp on the conditioner!

Does hair dye get darker the longer you leave it?

Does hair dye get darker the longer you leave it?

Hair dye works by coating each strand of hair with colour, and eventually penetrates the cuticles of the hair and bonds with it.

You may think that if you leave the dye on for longer you would get a deeper colour – and this may be the case, but it may come at a cost!

Leaving the dye on for longer an cause issues with your hair; the chemicals can affect the health of the hair.

Most of the actual colour change happens within the first half hour of having the dye on your head.

You may notice more of a colour change if you leave the dye on for longer, but it is not recommended because it may damage your hair.

If you are after a stronger colour, it is best if you follow the instructions with regards to timing, but re-dye in a few weeks.

Should you shampoo after dying hair?

It is tempting, after dyeing your hair, to get the shampoo out and give it a really good wash. However, this is not the best thing that you can do for your tresses!

It is recommended that you leave it at least 72 hours before shampooing your hair after dyeing it.

This is because some shampoos can contain harsh chemicals which can strip the moisture from your hair, leaving it dry and brittle and prone to damage.

  • You should always wait at least the full 72 hours, longer if you can stand it.
  • When you do finally shampoo your hair, opt for a sulphate free version to avoid further damage.
  • Try to wash your hair with cooler water than you are used to; this will help your hair.
  • Stay out of the pool! Chlorine can affect the hair dye and can potentially change the colour, so avoid swimming for as long ass you can after dyeing your hair.

Here is a short video with a few good tips on how to maintain your colour:


Can I dye my hair again if I don’t like the colour?

If you have had a dyeing disaster, you may be tempted to reach for the dye box straight away, to try to sort the problem.

However, it is recommended that you leave it at least 4 weeks before you re-dye your hair, to avoid damaging it.

If you cannot wait a whole month with the colour that you have, give it 48 hours as a minimum – you can stay indoors for two days, right?

This is because as the colour settles on your hair it will “settle in” slightly, and the hue may change enough to give you confidence to show your face to the world.

You can use a bleach wash – mixing some lightener with a good clarifying shampoo – to lift the tones and lighten the hair all over.

Colouring the hair again, over the colour you don’t like, will not necessarily fix the problem – however it will work pretty well if you are colouring from light to dark.

Try to mitigate any damage to your hair caused by the extra damage by using gentle shampoos, to help gently clean the hair without damaging it further.

Hair masks are also a good idea; these will fill your hair with moisturising ingredients and nutrients, and can help restore your original condition.

Final words

As you can see, leaving hair dye in for too long won’t necessarily lead to an improvement of the colour.

Hopefully you now have a few more hints and tips on how to deal with it if you have overdone your home dyeing and you’re panicking!

  • Add Your Comment