Everyone interested in this topic knows that bleach is a very popular product that has the purpose of breaking down pigments in the hair and has one role – to lighten the hair.
It is also known that this is not a product that everyone knows how to work with and that it is safest to leave it in the hands of professional hairdressers. This is especially true due to the fact that there are many situations in which bleach can severely damage your hair, scalp, or skin.
If you plan on lightening your hair with bleach or you have already done so, you’ve probably heard many times that bleach has a bad reputation. There are reasons for that, especially if you want to bleach the hair that was previously colored…
Bleach raises many questions, but the one that we’re the most interested in today is: can you bleach over permanent hair dye?
In general – yes, but, there are many conditions that you should know and many pieces of information that should be taken into consideration before undergoing this hair treatment.
Information that you’re seeking and much more can be found below, so read ahead and enjoy all the information that we have prepared for you!

Can You Bleach Over Permanent Hair Dye?
As we’ve previously mentioned – you can. But, there are many factors that affect the end result of bleaching dyed hair.
- Hair quality – thinner hair must be hydrated and treated with hair care products more often.
- How long the hair has been treated with the dye – long-term hair coloring requires a longer process to the desired transformation.
- What type of dye is used on hair – whether it is a natural preparation, such as henna, or professional color. If it’s henna, there’s no help, no one will take that type of color off of your hair.
- Whether the hair is dyed – is it the entire length or just the root with each treatment?
All four of these factors are extremely important to take into consideration, especially if you’re bleaching your dyed hair for the first time.
One mistake with bleach is enough to ruin your hair for long periods of time that will require you to nurture your hair and practically not do anything to it. So in order to avoid that, take these factors into consideration.
Hair dye plays a significant role in this process since if you’ve used a hair dye that is low quality and doesn’t have any beneficial applications for your hair, it’s more likely that your hair is not as strong and as healthy as it could be.
Because of that, the best thing to do for your hair, regardless of whether you bleach it or not, is to nurture it and keep it in good condition so it withstands hard chemical-involved processes like bleaching or dyeing.
Let’s talk about one more thing.
Perhaps the most important tip for bleaching dyed hair is that, if you are dyed with henna, stay away from bleaching. Henna contains a molecule of plant origin – tannin, which binds to the hair cuticle.
As the color is transferred to the hair, henna binds to the keratin of the hair and reaches the heart fibers, the cortex. By closing the hair cuticle, henna enhances the hair’s resistance to external influences.
After using henna, you will have to wait and grow out your hair. Once dyed with henna, the hair retains its color permanently and is almost impossible to remove.
With plain hair color the situation is easier since here, the matter depends on the above factors. It is the most difficult in the case of black hair color, but even that is not impossible, you just need to be patient.
The less colored the hair, and the lighter the color, the easier it is to bleach it and get the desired shade.
In any case of bleaching, therefore, when working on natural, uncolored hair, and after coloring, it is recommended that you still leave it to a professional, especially in this case where you plan to expose already colored hair to bleach.
Related: How Long To Leave Henna On Hair?

Tips For Using Bleach
If the bleach is used correctly and in accordance with the structure of the hair on which it is applied, the outcome will be positive.
But, before we dive into the useful tips, we would like to advise you about two facts about this chemical that are extremely important to know.
The first one is the fact that you can find bleach in two forms – cream and powder. Depending on what you’re looking to bleach, you’ll want to use the correct form.
Bleach cream is used exclusively for bleaching roots, while the powder is used to bleach the hair along its entire length, and extract strands. Oh, and one more thing – bleach powder can be blue or white in color.
White type is used for dark hair, and blue (which neutralizes yellow tones) for hair that is yellow, orange, or light brown.
The second important topic is the fact that Bleach is not used alone, but in combination with hydrogen since it is the main and basic activator of bleach.
There are four types of hydrogen – 3%, 6%, 9%, and 12%. Depending on what you’re planning on doing with bleach, you’ll need one of these three hydrogen mixtures.
Here are some important tips on how to use bleach:
First of all, it is important to choose the right bleach. We mentioned that there is white and blue bleach powder. If the color of your hair is very dark choose a blue powder that is much stronger. If you have a light brown, orange, or yellow shade, white bleach powder is for you.
In addition to that, an essential thing is choosing the right hydrogen. That is, the percentage of hydrogen that is the smartest choice for your hair. Hydrogen is an activator of bleach, but in its case, more of the stronger hydrogen is not necessarily better for you.
That is why it’s always smarter to leave such decisions to the hairdresser since he will certainly estimate the required percentage that suits your hair, for the simple reason that they are much more experienced.
Using adequate hydrogen in the right proportions with bleach is what keeps your hair from side effects that can include:
- Drying hair
- Yellowing
- “Broom” looks
The two ingredients are mixed and applied to the hair. After some time, you get a new lightened hair look.
That particular time is also a very important determinant. The hairdresser is again the one who will determine how long the bleach should stay on the hair.
Someone needs 5 to 10 minutes to reach the desired shade and someone even more than half an hour!
How long you wait depends on many factors and there is no one-size-fits-all time, so your hairdresser will check every 2 to 3 minutes how the bleach lightening process progresses.
It is very important not to heat the hair while the mixture of bleach and hydrogen is on it! It’s recommended that you do not expose your hair to heat even after the process, at least for a while.
Did you know that where our scalp is warmer, lightning will occur faster than elsewhere?
The part of the hair above the neck is much colder. In order not to get colorful results, the hairdresser must check the process carefully and when he notices that the hair has got the right shade, he will immediately wash the bleach out of it.
You need a plastic bowl and a paintbrush. Do not use a metal bowl as chemical reactions may occur. Pour the bleach to the extent you need. The measure depends on the length of the hair and the degree of lightning.
At the end of the whole process, you need to wash your hair well from bleach because the goal is to remove even the smallest residue from the hair. It takes a long thorough washing of hair with a mild, natural shampoo without sulfate.
Your hair will need more attention after this treatment. After washing, apply a hair conditioner that will nourish and hydrate it. This is especially important for people that have damaged or weak hair since their hair follicles will need more time to recover from the bleaching process, and the conditioner will help immensely with that.
Read Also: How Long To Leave Bleach In Hair 30 Vol?

Final Thoughts
Now that we’ve told you everything we know about this topic, let’s go through some of the most important facts once more.
In short, yes, you can bleach over permanent hair dye, but you must be aware of all the factors and consequences for hair that can befall you if you are ruthless towards your hair.
If you scroll back up, you will find everything you need to know to prepare the right combination of hydrogen and bleach for your hair type.
Also, don’t forget to check how long it takes for your hair to keep a mixture of hydrogen and bleach on your hair to get the desired effect and still keep your hair from drying out.
Remember to avoid all exposure to heat when it comes to your hair, especially during the process and immediately after.
In the end, we have some interesting information for you, so, you must have seen and heard many times that hair treated with bleach is covered with a bag and heated, it is by no means the way!
These are old methods that should be eradicated and forgotten. Hair should be exposed to the visual field, not heated, and closely monitor progress.
Lastly, don’t forget to make the airflow because the bleach has a very strong unpleasant smell!