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How Long to Leave Bleach in Hair | Things to Consider

Wondering how long to leave bleach in hair? It’s always best to do your research, especially when it comes to bleach. But don’t worry — you’re in the right place. Read on to learn everything you need to know.

What Is Bleaching Your Hair?

For a piece on how long to leave bleach in hair, a woman with blonde hair smirks at the camera in a studio

Olga Ekaterincheva/Shutterstock

Bleaching your hair involves removing color pigment (natural or dye) from your hair’s cortex, one of the inside layers of your hair strands. Bleaching will lighten your hair to red, orange, or yellow, depending on your natural color. Then you can take it a step further and go platinum. Before you bleach your hair, consider things like:

  • Scalp sensitivity
  • Hair condition
  • Your desired results (highlights, roots, lightening, or full platinum)
  • Processing time

When you bleach your hair, the processing time makes all of the difference. Rinsing bleach out too quickly will result in little change in your hair color. But leaving it on too long could cause major damage.

Read Next: Should You Bleach Your Hair?

How Long to Leave Bleach in Hair

To illustrate how long you should leave bleach in hair, a woman in gloves painting the hair of a woman in a salon


The perfect time to leave bleach in hair depends on your original color, hair texture, and desired results. But typically, here are a few rules of thumb:

  • Blonde hair: 15 to 20 minutes
  • Dark hair: 30 minutes
  • Fine hair: 10 to 15 minutes
  • Coarse hair: 30 minutes

The longest you should leave bleach in your hair is 30 minutes. If you let it stay on any longer, you risk making your hair brittle or even causing it to break off. Checking your hair every 10 minutes will give you a sneak peek of the results.

Your Ideal Look

Following the guidelines for your hair type will ensure you reach your ideal look. Leaving the bleach on longer than the time recommended for your hair won’t make it any lighter. 

If you want lighter hair, you can do another bleaching session in four to six weeks. Your hair will lighten three tones per bleaching session, so you’ll make progress towards your ideal look, even if you don’t get it the first time.

Time to Care for Your Hair

Because bleach makes your hair dry and brittle, you have to care for it properly. Even brushing your hair normally can cause bleached ends to break off, so you’ll need to be gentle. 

After you’ve bleached your hair, consider keeping it healthy with:

  • Nourishing hair masks
  • Lukewarm water for washing
  • Conditioner after using shampoo
  • Lightweight hair serums you can wear all-day

That said, you should know what happens if you leave bleach in for too long or not long enough. Read this carefully, because it could have some pretty serious consequences.

Read Next: How to Bleach Your Hair

Leaving Bleach in Hair for Too Long

To illustrate what happens if you leave bleach in hair too long, a blonde woman holding the ends of her damaged and burned hair

Roman Smaborskyi/Shutterstock

Many people think that their hair will get lighter the longer they keep the bleach in their hair. The truth is, after 45 minutes, your hair is as light as it’s going to get for that session. You need to rinse out the bleach before it starts frying your hair.

Scalp Burns

Bleach is an aggressive substance that contains ammonia and hydrogen peroxide. These chemicals can burn your scalp if it has extended contact. If you feel your scalp start to burn while you’re bleaching your hair, wash it off immediately.

Dry Hair

The chemicals in bleach dry out your hair. If you leave the bleach in for too long, it will make your hair dry and coarse. When you try to style your hair, it will feel brittle and look frizzy. 

You can help dry hair by using coconut oil and conditioners, but it’s best not to dry your hair out too much in the first place.

Leaving Bleach in Hair for Too Little Time

Guy who messed his hair bleach up and it turned yellow gets his hair dried


When you’re bleaching at home, you might get nervous about how long to leave in the bleach. If you wash it out too soon, the chemicals won’t have a chance to make a difference in hair color.

Undesirable Results

Bleach lightens three tones per session, but if you don’t leave it on for the full time, you won’t get those results. Instead, you might have to bleach your hair all over again to lighten it enough.

Since bleach is harsh on your hair, you have to wait four to six weeks to bleach it again, so you’ll have a long time not loving your current hair.

Read Next: How to Remove Hair Dye

Discolored Hair

If you don’t let the bleach stay on your hair the recommended time, you might end up with discolored hair. The bleach won’t lighten to the degree it’s supposed to, so you might have a color that’s not much lighter than how you started.

Apply the bleach carefully so it’s even. If you don’t distribute the bleach evenly and then wash it out too early, you might have a patchy look when you’re done.

Things to Consider

If you’re ready to bleach your hair at home, remember these key tips:

  • Try a test before you do your whole head. This makes sure you’re not allergic to bleach, and you’ll see the potential color results before you’re too far in.
  • Wear gloves when you apply the bleach so you don’t burn your skin.
  • Check your hair every 10 minutes while you’re bleaching. You might find that you’ve reached your perfect shade well before the timer goes off.
  • Bleach dries out your hair. If you leave bleach in for too long, it can damage the hair and dry it out. 
  • Even if you wait several hours, bleaching your hair twice in one day will still cause damage. It’s best to wait anywhere from four to six weeks before bleaching again.
  • Apply bleach one inch away from your scalp first. Let it sit, and then put bleach on your roots for the last 15 minutes of the session. Your roots are new hair that doesn’t need as much bleach to remove the color.

Frequently Asked Questions

Woman shocked her hair didn't turn out because she didn't read our guide on how long to leave bleach in hair

Mix and Match Studio/Shutterstock

Now you know how long to leave bleach in hair, you might still have some questions. We’ve rounded up a few popular questions to help you decide what steps to take next.

How Does Bleach Work?

Bleach opens your hair’s cuticle and dissolves the melanin, which is what gives your hair its natural color. But bleach also destroys keratin, which is what keeps each strand healthy. That’s why it’s important not to leave the bleach on for so long that it ruins all of your hair’s health.

Read Next: Keratin Treatment Guide

How Do You Know When Bleach Is Done Processing?

The most important factor in bleaching your hair is knowing how long to leave it on for your hair color and texture. If you follow that timeline, you can set a timer and know when your hair has reached its final color for the round of bleaching.

In general, as the bleach dries on your hair, it’s done processing. It won’t lighten your hair more after that point, so you can wash it off. 

What Should I Do After Bleaching My Hair?

You don’t need to wash your hair very often when it’s bleached. Because the strands are drier than normal, it’s better to wash them less frequently. But you still need to apply conditioners, hair masks, and serums to keep your hair moisturized.

If possible, stop using heat to style your hair. Hairdryers, straighteners, and curling irons dry your hair out already, so using them on bleached hair can cause breakage.

Read Next: How to Straighten Your Hair Without Heat

Should I Bleach at Home or Go to a Salon?

This question depends entirely on you. If you feel comfortable bleaching your hair, you can do it at home. It’s much cheaper this way.

If you’re worried about your hair, it’s worth the peace of mind to go to a salon. You’ll pay more, but you’ll be in the hands of an expert. They know what to do to your hair and can give you tips and products to take care of your hair.

How Long Should You Leave Bleach in Hair?

Bleaching is a way to lighten your hair by eliminating the natural colors. You’ll get a lighter, tinted look with the first application. Many people love this look, so you can stop there or bleach again until you’re platinum.

There are so many different hairstyles to choose from, but bleaching gives you a unique look. If you feel ready to bleach your hair, make sure you follow the tips and timelines above to get the perfect shade for your hair.