What happens if you leave hair dye in for less time?

  • If you leave the dye on your hair for less than 40-45 minutes, the chemicals will not penetrate into the hair fiber. So, your hair color will not change.
  • It is essential that you respect the exposure times recommended by the manufacturers.
  • If you want a lighter hair color, you will have to choose a different shade. You will not be able to lighten your hair color by leaving the dye in your hair for less time. If you’re worried that the time you leave your hair dye in will damage your hair, I’ll tell you how to avoid it.

fixing highlights

I usually open the salon at 10:00am. However, I always arrive at least an hour before to get everything ready, so that the atmosphere is relaxed, neat and ready to receive my clients when they come in.

That’s why I was surprised when, at 9:30am, I heard a few insistent knocks on the door of the shop. I was torn away from my morning newspaper reading.


When I went to see, I discovered that it was one of my youngest customers, Candela, who had a really unsettled look. Although it was a little less than half an hour before the opening time, I opened the door for her and she practically threw herself into my arms.

Just then, she threw a few words at me, of which I only understood two phrases: “desperation” and “I left the dye less time”.


 When I looked at her hair and I realized what had happened. She had decided to dye her hair, but she hadn’t respected the exposure times.  



The color hadn’t had time to hold on to some sections of her hair. When I asked her why she had let the dye work less time, she said she was afraid the dye would damage her hair.

Oh, God! When will they understand that hair products have a proper use, specifically described by the manufacturers?


 Exposure times of dyes are not a whimsical matter or something the manufacturer uses to justify the price. It’s the time it takes for the dye to work within your hair fiber and achieve the change you want.  

Candela’s drama ended when we applied a new dye to her hair. This time, of course, we left it on long enough.

Do you want to know why it’s so important that you respect the dye exposure times?


Then, stick with me, because I’ll tell you:

  • How the dye works on the hair fiber during the exposure time
  • How to protect your hair before applying the dye and respecting the exposure times
  • How to choose a lighter tint, so as not to have to let the tint act less time


Tabla de Contenidos


How the dye works on the hair fiber during the exposure time

at least forty minutes

To understand why you shouldn’t leave the dye in for less than the prescribed time, you must first know how it works.

The dye is applied with developer or cream developer that is hydrogen peroxide. It is usually used with 20 volume peroxide.


In addition, the dye contains ammonia. So, if we add the peroxide to the ammonia, we are dealing with two chemicals that react together in the hair, but for different functions:

  • The developer opens the cuticles so that the hair fiber absorbs the color
  • The ammonia in the dye is responsible for fixing the color in the hair fiber


quantities for the mix

So, when you apply the dye, the chemical reaction that is triggered takes about 20 minutes, during which the peroxide will open your cuticles completely.

Up to now, no news about the new color. So, then, the ammonia in the dye will work during the next 20 minutes to fix the new shade in your hair.


  •  If you leave the dye in for less time, the coloring process will not be completed.  That is, you will not be able to fix the new color to your strands. You will also make an even bigger mistake. If you remove the dye after twenty minutes, your cuticles will be open.
  • That will cause the hair fiber to break. When hair breaks, split ends appear, leading to a haircut.
  • If you remove the dye after thirty minutes, you will not allow the ammonia to fix the color correctly in your hair, resulting in a weak tone that will fade quickly.


 So, for your dye to be perfect, you need to respect the exposure times, which will always be between 40 and 45 minutes.  

We’ll look at some of the issues that might lead you to think about reducing that time. For example, to avoid damage to your hair.


How to protect your hair before applying the dye and respecting the exposure times

for everyday use

All hair processes involving chemicals generate damage because they seek some kind of change in the hair structure. Some may be severe, such as bleaching, and others much less harmful, such as dyeing.

The damage generated by the dye is minimal and will not leave your hair dry, dull or porous, as it may be the case with bleaching. If not, imagine the number of lawsuits coloring companies would receive!


 If you’re worried that the dye will dry out your hair, you need to prevent damage and not let the dye work any less. 

How do you prevent the adverse effects of dye on your hair?


  • Apply coconut oil from root to tip, 24 hours before dyeing, so your cuticles will be more flexible.
  • Do not wash your hair for 48 hours before coloring, because the hair’s natural oil will protect it from chemical wear and tear.
  • Do not apply peroxide dye with more than 20 volumes, so as to avoid the chemical reaction from being excessive
  • Apply about 8-10 drops drops of coconut or argan oil to the dye mixture, so that your hair fiber is hydrated during the process.


Now, if you want to leave the dye in for less time, because you want the color to be clearer, you’ll be making a big mistake. I’m talking to you next about that.


If you’re looking for a lighter shade of dye, do this

The only way to make your color lighter is by applying a lighter dye.

You will not achieve it leaving the dye less time, or mixing it with water or shampoo. The only thing you’ll achieve by removing the dye early is a half-faded, untidy, dull color, like Candela did.

You must let the process come to an end if you want a successful result. If you want a lighter color, you must choose a lighter shade of dye.



If you want the dye to work properly on your hair, you should leave it in for 40 to 45 minutes.

If you rinse it out before that time, the only thing you will achieve is the color to not hold on to your hair fiber. You will have wasted time and money.

Always respect the exposure times recommended by each manufacturer because this is the only way to ensure the shade you want.


Deja Tu Comentario