Does hair dye kill head lice and nits?

WIll hair dye kill head lice nad nits

Your head is infested. It’s time to top up your hair colour. You need to know, does hair dye kill head lice and nits??

Nits. Ew! If you have small children, spotting the frantic itching and scratching of their scalp strikes fear into every parent. As well as fumigating the house, it will take a good does of a nit shampoo and raking their hair with a comb to get rid of them. Good luck with that!

Of course, this means there’s a chance you’ve got them too. Unfortunately, no one’s too old for head lice! So rather than go through the same hair frazzling and raking process, if it’s time to dye your hair, does hair dye kill head lice and nits? Let’s find out!

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What’s the difference between head lice and nits?

Head lice are like human fleas. They are teeny, grey/black parasitic insects that can be as big as fleas and resemble tiny earwigs.

They live on human hair and scalp and suck blood to survive, hence the itchiness. Scarily, they can live up to a month and lay eggs, known as nits, up to five times in one day. Yikes!

Nits are head lice eggs. These are microscopic white specks that are found in clusters on warm parts of the head – typically behind the ear and in the nape of your neck.

Contrary to popular belief, nits don’t care if your hair is clean or dirty. They are pretty much impossible to wash out without a chemical nit treatment.

Does hair dye kill head lice?

Most head lice treatments come in lotions or sprays from your local chemist or supermarket and work by suffocating the head lice with chemicals.

Permanent hair dye is said to work in a similar way to effectively kill head lice by suffocating them with the ammonia that the hair dye contains.

To use it this way, use your hair dye normally as instructed but spend extra time rinsing and combing to shake off the dead lice.

Be warned that if you have nits, you’ll still need to use a nit comb and the hair dye may not have successfully killed off all of the lice. So you may need to follow up with a medicinal treatment after a week or so.

Other hair dyes such as semi-permanent and demi-permanent won’t be strong enough to kills off headlice as they don’t contain strong enough chemicals to suffocate the little cretins.

Does hair dye kill nits?

Hair dye will not kills nits as nits have a solid shell coating that can’t be penetrated with chemicals.

The only effective way to remove nits is to use a head lice treatment that will coat the hair shaft, making it slippery. Then, using a nit comb, you can loosen the nits’ grip on your hair by scraping them off.

As you can imagine this is rather damaging for your hair! So you make sure you condition it well with deep conditioners suitable for coloured hair before and after treatment.

Can I use a nit treatment if I’ve just dyed my hair?

It’s needs must if you have nits and you need to act fast to kill off the head lice. Not to mention get rid of the discomfort of sharing your head with blood sucking beings!

So while it’s not a great process to do if you have dyed hair, it’s a necessary one. The sooner you do it the better.

Just make sure you use deep conditioners before and after the process to replenish and restore your hair as much as possible.


  • Use permanent hair dye only. Only hair dye that contains ammonia will kill head lice.
  • Use hair dye to kill nits only if you’re due to dye your hair anyway. You’ll still need to go through the regular nit removal treatment and process.
  • Condition your hair with deep conditioners suitable for dyed hair before and after the process to restore moisture to your hair and smooth the hair shaft.


  • Don’t use hair dye specifically for the purpose of killing head lice. Medicinal treatments will be more effective in the long run.
  • Don’t worry if you have dyed your hair recently and now have head lice. You are likely to notice it affect the condition of your hair more than the colour.
  • Don’t dye your hair straight away after using nit and head lice shampoos and treatments. Wait for at least a week for your hair to regain some natural oils and elasticity so it’s strong enough for hair dyeing.

Find out more answers to common hair dye questions over on our hair dye FAQs page.