How Long Should You Leave Bleach in Your Hair? Expert Tips for Every Hair Type.

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When it comes to hair, the question of how long should you leave bleach in your hair can get a bit complicated. The perfect timing varies depending on your hair type and the level of lightness you’re aiming for.

One golden rule that hairdressers universally agree on is to avoid overdoing it. Getting the duration right is crucial because leaving bleach on for too long can lead to dry, brittle, and damaged hair – a situation that’s not only looks ick but is also really hard to fix.

That’s why we’ve put together this guide on how long you should safely leave bleach in your hair based on your hair type, important things like the strength of bleach used, and what sort of result you want to achieve. We hope it helps!

How long to leave bleach in your hair infographic.

The maximum amount of time recommended for leaving bleach in your hair is 30 minutes. This is so you don't damage your hair with long-term use.

dependent on the hair type, texture and desired reults.

How Long to Keep Bleach in Your Hair: Finding the Right Balance.

Let’s clear up a common misconception: leaving bleach on your hair longer doesn’t necessarily mean better results. The key is finding the right amount of time.

Recommended Bleaching Time.

Experts and hair enthusiasts alike, including those at Healthline and Stylecraze, suggest a maximum of 30 minutes. This timeframe helps prevent potential hair damage due to overexposure.

Risks of Overdoing It.

There’s a bit of a myth floating around that leaving bleach in your hair for hours will intensify its effects.

This isn’t the best approach, as it can lead to brittle strands and an unintended orange tint. This is echoed by the insights from kintegraresearch.com, who talk about how timing is super important.

Striking the Right Note.

It’s about achieving that perfect lightness while keeping your hair in good condition.

Overextending the bleaching time can cause more harm than good, undoing the hard work and care you’ve put into maintaining your hair’s health and appearance.

By sticking to the recommended 30 minutes, you’re more likely to reach your desired hair color while maintaining its health and vibrancy. It’s all about finding that perfect timing for the best results.

What the experts say:

Expert Insights

“The duration you leave bleach in your hair depends on several factors, including your hair type, its current color, and the desired end result. Typically, bleach is left in the hair for anywhere from 20 to 45 minutes.”

Muriel Perez, Certified Hair Restoration Specialist

Expert Insights

“It will depend on the level of the hair being bleached & the strength of the developer being used. Darker haircolors have more red underlying pigment that needs to be ripped through to get to the yellow pigment.”

Versions Vividamnesia, Master Hair colorist, cuts, fades & chemicals 

Expert Insights

“How long the bleach should be in your hair really depends on what you’re aiming to achieve. The higher the volume of developer used, the less time it should sit on your hair to avoid frazzling your hair.”

Enza Piazza, Hair Stylist & Color Consultant

What is hair bleach?

Hair bleach – it’s more than just a product on your beauty shelf; it’s a powerful formula primarily made up of hydrogen peroxide.

It’s our go-to solution for:

  • Achieving Dreamy Blonde Tones: Whether you’re yearning for soft, honey-blonde highlights or daring to go full platinum, hair bleach is your magic wand.
  • Transforming Your Look: Bleaching can completely revamp your style, giving you a fresh, bold new look.
  • Preparing for Color Changes: Sometimes, you need to lighten your hair as a base for vibrant colors to pop.

How does hair bleach work?

It’s a strong chemical that can break down the protein in hair. When it does this, it lightens your hair over time.

As the protein breaks down, the strands become lighter and paler until they get all of the color out of their core.

But how exactly does it do its magic?

According to the American Academy of Dermatology, hair bleach works by altering the natural pigment of your hair, allowing for a spectrum of lightening effects.

The formula changes the color of your hair by first opening up the hair cuticle so that it can penetrate and change your hair coloring, then closing down the cuticle again after processing.

In order to bleach your hair properly, you need to know what type of bleach to buy and how you should be applying bleach to your hair. Your hair type matters too.

Studies published in the Journal of the Society of Cosmetic Chemists have shown how bleach interacts differently with various hair types. The impact of bleach on fine, light hair is quite different from its effects on thicker, darker locks.

Knowing all of this is the secret to avoiding unwanted results and achieving the perfect lightening outcome.

what does bleach do to hair infographic - alkaline hydrogen peroxide in the developer causes the hair cuticles to lift and open. Bleach travels under the cuticle tot he hair cortex where it oxidizes the melanin and causes it to lost its color.

Expert Insights

“You should always read the directions before mixing or applying. This is not just advice for you, but for colorists and everybody else too. In the past, I have seen manufacturers change their instructions on chemical processes that have been around for a long time. So, it is just a good habit to get into.”

Cindy Marcus, Editor-in-Chief at Latest-Hairstyles.com

Will bleach damage my hair?

It’s quick, easy, and relatively affordable– all the makings of a great beauty hack! But don’t let anyone fool ya; bleaching your hair can be a damaging process at times.

The harsh chemicals used in hair bleach kits have been known to cause split ends, dryness and breakage.

Of course as with all dyes, not everyone experiences these side effects as everyone’s hair is different but some common problems are highlighted below:

  • Dryness caused by stripping or removing natural oils from your scalp
  • Brittleness caused by the loss of moisture in the strand/shaft.
  • Damage caused by chemicals (commonly ammonia and ethanol).
Bleach bath mixture 2

General Guidelines for Bleaching Times.

The most important rule in bleaching? Never keep it on for more than 30 minutes. But remember, this isn’t a one-size-fits-all solution. The ideal timing can vary depending on your hair’s unique characteristics and the strength of the bleach you’re using.

Bleaching Different Hair Colors and Textures

Every hair color and texture has its own bleaching needs.

  • Light Blondes: If your hair is already quite light, you might only need a short bleaching time. Aim for about 10-15 minutes, as your hair lifts color more quickly.
  • Dark Browns and Blacks: These hair colors often require a longer bleaching time to achieve noticeable lightening. However, be cautious not to exceed 30 minutes. Starting with a 20-minute mark and checking the progress is a good approach.
  • Fine or Delicate Hair: This hair type processes bleach quickly, so keep a close eye and limit the bleaching time to prevent over-processing.
  • Thick or Coarse Hair: Such hair types may need a bit more time, but again, it’s crucial not to exceed the 30-minute maximum.

Specifics on Bleach Volumes: 10, 20, 30, 40

Bleach comes in different volumes, each designed for a specific level of lightening.

Lower volumes like 10 and 20 are gentler and suited for subtle changes or hair that’s already light. Higher volumes like 30 and 40 work faster and are used for more significant color changes or darker hair.

However, they also increase the risk of hair damage if not used correctly. You need to match the bleach volume to your hair type and desired outcome, and adjust the bleaching time accordingly to protect your hair’s health and integrity.

Bleach volumes and development time infographic 1

How long should you leave 40 volume bleach in your hair?

40 volume bleach is very potent and isn’t supposed to be left in your hair for more than 10-20 minutes.

If you have coarse or very dark hair, you can leave it a few minutes longer. But make sure you keep checking it’s effect so you can rinse it out as soon as it’s achieved the colour you want, before it causes too much damage.

How long can you leave 30 volume bleach in your hair?

For those with dark hair, we recommend leaving volume 30 on for no more than 20 minutes max – any longer and the result could be very damaging.

With lighter hair, you should only leave it on for up to 10 minutes before rinsing out and using a conditioner or hair mask to repair the damage done by prolonged exposure to high concentrations of hydrogen peroxide.

How long should you leave 20 volume bleach in your hair?

If you have blonde, light brown or red hair and are using the recommended developer to lift colour, you should follow instructions on package instructions for a time before rinsing out.

For darker shades of hair – black, dark brown, deep auburn – plan on leaving it in longer than 10 minutes.

How long should you leave 10 volume bleach in your hair?

Volume 10 bleach is the most common bleach that’s used in hair salons to create highlights, streaks, ombre and balayage styles.

That’s because it’s effective at lifting color without causing too much damage.

If you have thick hair, then the bleach will take longer because it has farther to go.

But if you have thin locks, then the time is cut down significantly.

10 volume bleach can be safely left in your hair for up to 30 minutes before the chemicals stop working and the hair starts being over-processed.

What kind of bleach should I use?

There are four main types of bleaching agents:

1.Peroxide – This is the strongest option since it contains 10% or more hydrogen peroxide. Over time, the hydrogen peroxide will lift the color of your hair without damaging it too much. It’s perfect for stripping hair color and bleaching dark hair to light blonde.

2.Hydrogen Peroxide Solution – This option is only 3% hydrogen peroxide so it’s not quite as strong as its more concentrated sibling. However, it still works really well and isn’t harmful to your hair either.

Peroxides are used most often by professionals instead of at-home bleach users because they need a stronger solution to work with their clients’ very dark hair.

3.Bleach Powder Mix – Bleach powder contains 10% ammonium bromate or hydrogen peroxide mixed into a powder form that can be easily applied to hair before being distributed evenly throughout strands of hair. Mixing powder bleach with developer is one of the cheapest ways of bleaching your hair at home.

4.Liquid / Creme Developer – This type comes in a solution that you must mix with either peroxide or developer cream before applying it to your hair. You can also use creme developer on its own if you are already light blonde but want lighter hair without too much damage. (This doesn’t work well on dark hair because it does not contain enough hydrogen peroxide for the job).

Each of these types has different concentrations which means some are stronger than others and require different lengths of time to achieve your desired shade.

What happens if you leave bleach on too long?

While bleaching your hair can be really fun, it can also go very wrong if you’re not careful. You could end up with a colour that isn’t what you wanted or even worse, damage your locks in the process.

This means leaving bleach in for too long – which can make your hair type become brittle and break easily – as well as not leaving enough time between treatments (which makes the colour uneven).

Expert Insights

“Leaving bleach on too long turns your hair into mush and it breaks while combing it. You will be left with brittle mushy hair.”

Lori Hartz, Salon Owner and Stylist

Check out this video to see how bad it can be!

YouTube video

Frequently Asked Questions.

Can I leave bleach in my hair for 2 hours?

There’s no point leaving bleach mixture in for any longer than 30-40 minutes as it will eventually stop working and stop lifting your colour.

This means all it’s doing after 40 minutes is frying your hair!

We really recommend doing a strand test before using bleach because there are so many variables at play when bleaching your hair or someone else’s.

You could have thicker or thinner strands, even the temperature of the water used, and what ratio of developer you’re using all affect timing.

How long do I leave bleach in brown or black hair?

Dark hair colours like black and brown can be really hard to bleach.

You may need to up the strength of the bleach or trying lightening your hair a few times to get the result you want.

You can use the maximum time for your chosen bleach. So up to 30 minutes. But bear in mind you may need to do a couple of bleaching treatments.

Always do a strand test so you know what’s in store and what colour your hair will lift to each time.

How long should you leave bleach on your roots?

Do you ever find yourself wondering how long should you leave bleach on your roots?

Well, the time that the bleach needs to stay on the hair is going to depend upon a few factors: firstly, if your hair is dark or light and secondly, if your hair has been dyed before.

If your hair is naturally light or you have virgin hair (hair that has never been dyed) then there’s no need for as much bleach as someone with light coloured or blonde locks so maybe only 5-10 minutes would be enough.

Whereas those of us with darker locks will have more of a wait on our hands. Remember that roots are naturally darker than the rest of our hair. And the grown out root look like blonde hair with dark roots is so on-trend right now.

So you don’t want to get your roots bleached platinum blonde or white-blonde as it just won’t look natural!

Should I try a bleach bath?

If you think that bleaching your hair will be too harsh for your locks, you can try a bleach bath.

Bleach bath hair is a gentler bleaching process that mixes bleach with shampoo to dilute the strength of the bleach.

If you’re wanting to lift your hair more than two levels, it may not be strong enough for you.

But if you want a more subtle lift or highlights, a bleach bath is totally worth trying out.

Should I shampoo after bleaching?

Many people ask whether it’s necessary to wash the hair after a bleaching session. The answer is yes!

You can’t bleach your hair 100% white. If you do not wash out the residues of the lightener, a yellow colour will still be visible in bright light.

Bleaching alters the structure of hair fibres and makes them weaker. When these strands are wet, they’re even more susceptible to damage from shampooing which can lead to split ends and breakage.

This is why one should apply a moisturising conditioner after washing and give your hair lots of love with deep conditioning treatments once a week.

Should I tone my hair after bleaching it?

Deciding whether or not to tone your hair after bleaching it is an age old question for many, and there is no straightforward answer.

Ultimately it depends on how you want the final result to look.

If you’re aiming for a classic blonde look, then toning is definitely something that’s worth exploring.

With the right shade of toner, you’ll be able to tone down any brightness and bring out the best in your color while taking away any brassy hues.

Plus its a great way to add some dimension and character to your look!

Don’t be afraid to consult with a professional salon stylist if you feel overwhelmed by all of the choices – they can help make sure you get the look you want without compromising on condition!

How soon after bleaching hair can you bleach again?

You can bleach your hair less than a day after bleaching it if you need to.

The sooner you do it, the more the dye will take. This is because the cuticle hasn’t fully closed yet and the inside of the strand hasn’t been exposed to natural oils that would slow down how quickly your hair takes the dye.

However, we recommend leaving your hair a couple of days if possible to let it recover from the harsh process of bleaching before dyeing it again. You don’t want to bleach your hair too often.

How to care for bleached hair.

When it comes to bleached hair, soft and silky is the name of the game!

As tempting as it is to just go for any old shampoo and conditioner, picking one specifically designed for bleached hair will make all the difference.

Bleaching your locks can be a tough process and it’s important to properly care for them afterwards.

From combing to deep conditioning treatments, there are tons of little hair bleach tips and tricks that’ll help keep your bleached hair happy and healthy.

Don’t forget to tone your hair color too. Using a purple shampoo once a week will help to keep any brassy, orange or yellow tones in your hair at bay.

So don’t forget to show your mane some extra love for maintaining soft, silky perfection!


Parting words.

Bleaching your hair is a process that can take time and patience, but it’s worth the final results.

What is the perfect time to leave bleach on your hair? It’s a question that has many answers. For most people, 10 minutes is sufficient. Other people might need 20 or 30 minutes for it to produce the desired results.

If you’re still unsure what time frame will work best for your hair, consult with an expert at your local salon who can provide you with more information on how long should I leave bleach on my hair?

Good luck!

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Authors

  • Nicola Freeman, Creative Director & Content Lead

    With over two decades of passionate hair dyeing experience, I've experimented with nearly every shade imaginable. My journey began long before blogging; as an award-winning copywriter in London and New York, I shaped narratives for iconic brands. However, when friends sought advice during lockdown for at-home hair dyeing, I realized my true calling. Beyond being your hair color expert, I'm a mom of two girls, wife to artist Tony, and an avid soccer player!

  • Enza Piazza, Hair Stylist & Color Consultant

    I’m Enza Piazza, your go-to hair stylist and color consultant with over 23 years of professional salon experience bringing vibrancy and life to hair of all hues. My Italian roots from sunny Sicily infuse passion into every snip and color, a passion that’s been recognized with top honor awards including bridal and party hair at the National Hairdressers Federation’s Championships. After training in Surrey, UK’s most prestigious salons including Head Master Academy, I embraced the entrepreneurial spirit and set up Enza Hair Styling, offering tailored hair care for 13 years, and treating each client like family. Away from the salon, I cherish moments as a proud Nonna to grandson Joseph and as a playful companion to my Jack Russell, Bo.