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How Long Do You Leave Bleach in Your Hair?

Bleaching your hair has become a kind of a trend nowadays. It is easy to be confused about whether to go to the hair salon or just do it at home.

We will be answering a few questions that will make this decision easier for you.

How Long Do You Leave Bleach In Your Hair?

What Is Hair Bleaching?

Hair bleaching is the process by which men and women make the shade of their hair lighter.

Many companies sell hair bleach, including L’Oreal, Clairol Professional, Wella, Schwarzkopf, Jolen.

They are easy to use, and many people prefer doing the bleaching at home, especially since the COVID pandemic has hit the world.

How Does Bleach Dye Hair?

Before we get into the process by which bleach lightens your hair, it is important for you to understand a few fancy-sounding words.

A pigment in your hair, called melanin, is responsible for giving it its color. If your hair color is dark.

It means that the amount of melanin present in your hair is higher than that of a person with blonde hair.

The outer-most layer of your hair is called the cuticle. This external layer protects your hair from outside agents such as heat and too much chemical treatment. Environmental damage includes too much sun or wind.

Your hair strands are made up of a protein called keratin. The more keratin your hair has, the softer it feels. 

When you bleach your hair, your hair cuticle becomes more porous. The chemicals in the bleach then dissolve the melanin in your hair by breaking down the protein bonds between the keratin particles in your hair.  

How Long Do You Need To Leave Bleach In Your Hair In Order To Color It?

The duration of bleach application depends on four things:

1. The natural color of your hair/current hair color (base color) – for people with dark hair, the duration will be longer

2. Your desired hair color or hair goals – The lighter the shade you want, the longer the bleaching process

3. The developer strength – Strong developers, will lead to shorter bleaching time

4. Porosity of your hair – The more porous your hair is, the faster it will change color because the absorption will be faster.

If this is the first time you are bleaching your hair, you can leave it in your hair for up to 30 minutes. For people who already have light hair, around 10 minutes should do the trick.

If your hair bleach is one of a higher volume, 15 minutes should be enough. 

Make sure you keep an eye on your hair, though. Everyone’s hair is different and reacts a different way! The time you leave it in should not exceed 30 minutes!

What Happens If You Leave the Bleach on Your Hair For Too Long?

Since it is a chemical, it’s pretty obvious that leaving the bleach mixture in your hair for too long is going to damage it. Here’s how:

1. It will make your hair brittle

2. It turns hair white due to complete loss of melanin

3. Hair will not be able to retain moisture and remain dry

4. Any skin that the bleach touched will react to it. You may feel itching, irritation, redness of the skin, swelling, etc.

5. Loss of keratin, leading to rough hair, will occur.

6. You may suffer from alopecia. It is a condition that is characterized by severe hair loss

7. For people with dark hair, their hair may even turn an orange color. Orange hair gives your hair a burnt-off look. Orange hair or hair with yellow tones is basically a sign of severe hair damage.  

Other Side Effects of Bleaching

The side effects can be divided into two categories, the first one are short-term and the other one’s having long lasting effects.

Short-term side effects include the following:

1. The Burning sensation of the scalp

2. Redness of scalp 

3. Itching of scalp

Other Side Effects Of Bleaching

4. Allergic reactions (esp for people who have contact dermatitis, psoriasis, or eczema)

5. Asthma reaction due to pungent smell of the bleach

6. Conjunctivitis (pink eye) if the chemicals come in contact with the eye

7. Discoloration of the areas it has come into contact with due to the harsh chemicals

Long-term side effects include the following:

1. Dry hair

2. Brittle hair

3. It can alter your curl pattern 

4. Creates the illusion of volume

5. Requires more effort to maintain hair care. Damaged hair needs more attention

In short, the bleaching process is a damaging process, no matter what kind of natural hair you might have.

The harsh chemicals are not only harmful to your hair but also to your skin and eyes. 

Are there any other Precautions to Take?

1. Wear gloves when you handle bleach to protect your skin.

2. Wear clothes you don’t usually wear so that if they are damaged, you don’t feel too bad about them.

3. Make sure the room you’re working in is properly ventilated in order to flush out the pungent fumes while you work.

4. Be quick while you work, or you will get an uneven result. 

5. Apply bleach to the bottom and then work your way up. That will reduce the time the bleach comes into contact with your scalp. 

6. Mix small amounts of the developer at a time. If left out for too long, it will foam up and lose its bleaching property. It will also harden. 

7. Section your hair before you work so that it’s easier for you to apply the bleach. Make sure you have healthy hair. 

8. Heal your hair before you bleach. If you have had any treatment done to your hair, wait two weeks before you take it to bleach. 

9. Stop using heat on your hair a few days before you want to bleach 

10. Don’t wash your hair three days before your set date

11. Make sure you don’t buy a cheap product while choosing to bleach. 

12. Hair oil, masks, and avocado application 2-3 weeks before you go for it is best. 

What is the Best Way to Take Care of Your Hair Post-Bleach?

1. Oil your hair. The oils you can use include coconut, oil, argan, and castor oils are great to help relieve dehydration.

2. A nourishing hair mask should be used frequently 

3. Sulfate-free conditioners and sulfate-free shampoo should be on your to-buy list.

4. Leave-in conditioners help regain all that lost moisture

5. Stop heat application until your hair regains some of the lost moisture


7. Decrease the frequency with which you shampoo your hair

8. Do not go swimming for a while. The chlorine in the water will make your hair even more brittle. You will also lose the color in your hair immediately.

9. Get a trim frequently to avoid split-ends. 

10. Protect your hair from exposure to the sun

11. Rice water improves the health of your hair from the inside

Bleaching at Home Vs. in a Professional Salon

Home Pros –

1. Less time consuming

2. Cheaper

3. You get to choose the product you use

Home Cons – 

1. Not professionally trained so that you might damage your hair

2. May damage skin

3. You won’t be able to see what you’re doing

4. You don’t know exactly how bleach works, so you might overdo it and get that platinum hair, yellow or orange tones.  

Hair Salon Pros – Your Hairstylist Will Be 

1. Professionally trained 

2. Able to guide you whether or not your hair will be able to withstand the treatment damage

3. Include treatment to improve overall hair quality 

4. Know the exact amount of time required for you to bleach your hair. 

Hair Salon Pros - Your Hairstylist Will Be 

5. Achieve the exact hair shade you need

Hair Salon cons – 

1. Time taking

2. Expensive  

Pros of Going to a Professional

It is essential that you remember that the people at hair salons are professionally trained to carry out different hair procedures.
They undergo months of training before they are allowed to touch a customer’s hair. There is a reason for it. 

Firstly, you are dealing with toxic chemicals. You need to be careful when you handle them, or you will cause damage to your hair, face, eyes, scalp, or hands.

They have been taught the precautions needed while they do the procedure to protect themselves and their clients from permanent damage. 

Have you ever noticed that the professionals there ask their colleagues to work on their hair instead of doing it themselves?

Well, there is a reason for it. It is impossible to do it on yourself because you cannot see the back of your head. If you do it yourself, chances are you will not have an even finish.

You should know that everyone has a different hair type. For virgin hair, the duration of the procedure will be longer than the hair has been treated before.

The professionals will be able to inform you whether or not your hair will be able to withstand the damage from the chemicals that you will be applying to your hair. 

These days, the most popular products to lighten your hair that are used at salons are not bleach.

New technology has helped companies introduce products that are ammonia-free.

That results in less damaged hair. You would only know it by extensive research or by going to the salon.

Pros of Bleaching Your Hair at Home

Ever since the pandemic hit, people have become more and more reluctant to leave their houses and interact with others.

The safest way by which you can color your hair when it comes to COVID is by doing it at home.

When you bleach your hair at home, it saves a LOT of money.

An average at-home kit costs range from $24.99 to $150, depending on the brand you go for. 

Hair salons take more time to complete the procedure, so doing it at home is definitely faster. 

Cons of Bleaching Your Hair at Home

The expertise needed to bleach hair is something you lack. The hairstylists at the salon have completed courses to finesse this procedure, whereas you are still a newbie.

You may apply it on your scalp by mistake; you may not take the proper precautionary measures that are needed.

You may harm yourself in the ways mentioned earlier in the article.

You cannot see your hair behind your head. Since you’re doing it blindly, there are no guarantees on how your result will be.

The bleach kits do not know the type and texture of your hair. So it is safe to assume that the time given on the box may or may not be appropriate for your particular hair type.

You may damage your hair irreversibly if you put bleach in your hair longer than needed.  

How to Tell When It’s Time to Remove Bleach?

1. Keep in mind the tentative time written on the box of those bleach kits.

Keep on checking your hair over and over. When you have achieved the perfect shade, remove it immediately.

2. Do a strand test. As in, bleach a single strand of your hair and time it. Once you know which shade you want and how much time it takes, repeat it but now do the bleach job on your entire hair.

The amount of bleach in hair should also be noted.

How Long Should You Leave 10 Volume Bleach in Your Hair?

Since this is the lowest concentration of hydrogen peroxide developer, it is the best option for people using this for the first time.

The max amount of time you can keep it in your hair is about 45 minutes. There should be little to no hair damage in this case.

How Long Should You Leave 20 Volume Bleach in Your Hair?

The standard time it can be left in your hair is about 20 to 40 minutes.

Since it’s not very strong either, you have to remember that it will only change 2 to 3 shades from your natural hair color.  

How Long Should You Leave 30 Volume Bleach in Your Hair?

The max for this one should be 15 to 30 minutes. Since it is pretty strong, you need to be vigilant while applying it, or it may lead to irritation, burns, etc. 

How Long Should You Leave 40 Volume Bleach in Your Hair?

With 12% hydrogen peroxide, this is one of the strongest ones out there.

When you start feeling a burning sensation, immediately rinse it off! You can only leave it in for 20 minutes max. 

What’s the Difference Between Hair Volume Developer Strengths?

The difference basically lies in the strength of the reacting agent, hydrogen peroxide. The different percentages of H2O2 are as follows:

1. 10 volume – 3% developer 

2. 20 volume – 6% developer

3. 30 volume – 9% developer

4. 40 volume – 12% developer

Basically, if you want to lighten your shade by only 1 to 2 shades, ten volumes should be your choice.

If you want to change your dark brown hair to platinum blonde, a higher percent developer should do the trick.  

How Long to Leave Hair Bleach for Highlights?

The idea is the same, be it for your whole head of hair or just highlights. It depends on your hair color and the kind of highlights you want to go for.

That being said, highlights are usually done in very dark hair, so the average time should be between 20 to 30 minutes, depending on the mix you use. 

Why Apply Bleach When Dyeing Your Hair?

There are a lot of people with a dark base color. As in, the natural color of their hair is very dark.

Bleaching is needed when such people want to cut down their shade and bring it to lighter colors.

That is because the natural color of your hair will not be able to catch the new color you want because it is either a darker shade than the one you want.

Because it is already treated, and dyeing over that will not give you the exact color you want.  

Is 30 Volume Developer Bad For Your Hair?

Because the amount of hydrogen peroxide is high, it is very likely to damage your hair, scalp, and skin.

That causes irritation and really bad allergic reactions. You should not use it unless you know what you are doing.

Is 30 Volume Developer Bad For Your Hair?

If you don’t have anyone with you while you’re changing your black hair to a more exotic color, please refrain.

Bleached hair can be very difficult to deal with if not done properly. 

How Long Do I Leave Bleach in Brown or Black Hair?

The period of time is determined by the kind of developer you’re using.

The 10 and 20 volume developers will not be able to do anything to such dark-colored hair in a single sitting.

If you use developers with such a low percentage, you will have to prepare yourself for multiple sittings. 

If you go with 30 or 40 volume developers, you will need to make sure that your time is right to the second.

A 30 volume developer will be good for 30 minutes, and a 40 volume developer will be good for 20 minutes, not a second longer.  

How Long Do You Have to Leave Bleach for Your Roots?

The average time is 15 to 40 minutes, depending on the developer you use. 

Should I Try a Bleach Bath?

If you have fragile hair, a bleach bath could work. You can easily lighten your shade through this method.

Use a 10 or 20 volume developer; mix it with shampoo and powder bleach.

Split your hair into sections, wet your hands and hair, and apply away! Put a shower cap for 30 minutes, and then rinse with warm water.

Should I Shampoo after I Bleach?

Simple answer? No. Do not shampoo until after one week of your procedure. 

How soon after Bleaching can you Bleach Again?

To reduce the amount of damage done to your hair fibers and the hair follicle, it is wise to avoid using bleach a few weeks after your first try.

Even if you are not okay with the level of lightness, you have to wait until your hair is strong enough to deal with such toxic chemicals again.

I am sure there must be some change from your base color, so waiting is best. 

Final Advice About “How Long Do You Leave Bleach In Your Hair?”

Now that you have all the information, I hope the decision to hair dye at home will be a little more educated.

To give you a quick conclusion, the time taken to bleach your hair at home depends on the type of developer you use.

Once you have bleached your hair, use dry shampoo and deep conditioner to make sure you keep your hair in its most pristine condition. Good luck!

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