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What Happens If You Leave Hair Dye In Too Long?

What Happens If You Leave Hair Dye In Too Long?

Modern-day life can get a little hectic; surely you felt it too. If you ever left the hair curler on by mistake, you know what we’re aiming at here. 

What happens if you leave hair dye in too long, though? Is there something specific you should do to fix it?

The answer is – not a whole lot will happen! At least not to the naked eye. 

If this unfortunate slip brought you here, don’t move a hair strand! Take a moment to figure out what’s happening inside your hair right now – and what should be your next “rinse.”

What Builds The Hair Strand?

Indeed, you’re made of courage and patience since coloring your hair is a risky choice – but could the same be said about your hair?

This time we should start from the bottom. There are tiny holes in your skin and, in this case, the scalp. They’re called hair follicles and at the bottom of their sacs are special cells that reproduce for only one purpose – to give your hair new cells! 

These new cells get stacked on the root of the strand, causing it to grow longer.

They deserve a paycheck of their own, right? 

The living tissue hides in these follicles, but the shaft – the part that you can see and probably call the strand – contains dead cells. That’s one of the key things you should know. Why?

It means you can hurt your skin, and it will heal – but when you hurt your hair, that’s not the deal!

The best thing you can do to mend the “scar” is to repair the damage as little as you can, or call it quits and cut it a little above the “wound.”

Hair Layers 

Each hair shaft has a few distinct layers: 

  • The cuticle 
  • The cortex
  • The medulla (which is of no importance for hair dying, by the way)

The cuticle is the outermost layer, and it’s made of flattened cells that overlap like tiles on a terra-cotta roof. They have the same function, too – protecting the inside “residents.” 

You can feel this structure if you do a little experiment:

Take one strand between your fingers and slowly move them from the root to the tip, and it will feel slick and smooth. 

Now do what we women love the most – do the opposite!

Take the same strand and move your fingers slowly from the tip to the root. Can you feel how the surface is a little rough? 

That means your fingertips are going in the opposite direction of the cuticle cells’ alignment, and you’re bumping into their edges.   

That’s the secret that hides behind puffy hairstyles!

Besides this hairstyle, sunlight irradiation and frequent hair washing could damage the strand’s surface or the cuticle.

Now, let’s go beyond the surface. 

The middle layer is the cortex, and it’s made up of long strands of protein that twist like the curly telephone cord around the medulla. So, when you stretch a hair strand, it will show you just how much those protein bands can stretch, too. 

Their main chorus could sound like this:

I’m elastic; it’s fantastic!

While we’re at it, you can learn more about your hair quality here:

Keep track of how fast the hair dye develops. Finer and higher porosity hair absorb the pigment more quickly than thicker and lower porosity hair.

The Pigment In Your Hair

Color is the reflection of light off of the colored pigments called melanin. These pigments can be dark, called eumelanin, or yellowish to reddish, called pheomelanin. Sometimes, there can even be an absence of pigment, called albinism.

So, this means that by changing the color of your hair, you’re just replacing the molecules that the light reflects on when they hit your hair.

Where could the pigments be hiding?

The pigments of melanin responsible for giving the hair its natural color hide among the protein strands – having double protection from the translucent cuticle cells. So, in essence, when you have split ends, you slip that cuticle protection right open. 

Here’s a piece of advice: The initial condition of the cuticle could be an essential factor when it comes to damaging your hair, so we recommend being extra protective of your hair right from the start!

Related: How Long to Leave Hair Dye in Your Hair?

Choose The Right Type Of Hair Dye

The dye you choose is, in a way, the warrior you get – and in this case, the fight is against your hair’s natural pigments.

With that said, hair dyes are generally divided into three categories, depending on the level of “aggression” and how lasting the effects are:

  1. Semi-permanent colors
  2. Demi-permanent colors
  3. Permanent colors

Knowing the category of the dye you used could be crucial for understanding its impact on your hair – especially if you left it in for too long!

1. Semi-Permanent Colors

Semi-permanent is level one and adds color without making dramatic changes. The hair dye contains tiny color molecules that enter the cuticle and go straight for the cortex – but they don’t interact with your natural pigments. 

Who doesn’t love a tease, right?

All jokes aside, since the color molecules are small, they leave the hair shaft after only several rinses, leaving your hair as it was. This type of dye generally lasts for 6 to 12 hair-washing cycles.

Most importantly, semi-permanent dye won’t change your natural hair color since it contains no ammonia or peroxide.

2. Demi-Permanent Colors

Now, this would be level two and is a bit more dangerous. Such hair dye contains the so-called pre-color molecules that are smaller in size. However, when they reach the hair cortex, they pair up into larger molecules. 

Size matters, as it turns out: 

Larger color molecules take longer to wash out, usually around 24 to 26 rinses. The dye doesn’t contain ammonia and peroxide, though.

3. Permanent Colors

And here we have level three – the most effective if your goal is a significant change since both ammonia and peroxide are used.

Some even say that the chemical reaction between these ingredients is so strong that it kills lice

Here, tiny color molecules invade the cortex and react until they expand to a size that can’t be washed out. But bigger isn’t always better, as it turns out. 

That means the best thing might be to get a haircut – or wait until the colored hair grows out.

Previous Color Choices: The Ghost Of The Past 

Sometimes previous choices can haunt you, but is this the case when it comes to hair, too?

If you have blonder hair and you chose to go darker, permanent hair dyes rely on the interaction between the ammonia and peroxide to form a new color base in your hair strand. 

But if you’re choosing to go from darker to blonder there’s an additional step: 

First bleach is used to physically strip the pigment molecules from the strand, then permanent colors create a new base color thanks to the ammonia-peroxide reaction. 

Unlike their permanent counterparts, semi-permanent colors serve as a “topcoat” of sorts here.

Leaving The Hair Dye In: Excuse Me, What Time Is It?

It’s time to rinse the hair dye off!

On average, it takes from 30 to 45 minutes for most hair dyes to do the job. Knowing this makes no difference, as you should always read the instructions and the ingredients on the packaging you’re using.  

If you had any doubts about it, no, leaving the dye on longer than recommended won’t make the color darker – or make it last longer!

It takes roughly half an hour for the ammonia and the peroxide to penetrate the cuticle and get to the cortex. The final 15 minutes are meant for color molecules to fully develop. 

Take note: 

Non-permanent colors still contain a certain amount of chemicals, as well, and can have a drying effect on your hair, much like their permanent counterparts.

The two mentioned components are also considered to be one of the most dangerous in the hair dye formulas. That’s why you should dispose of the package right after usage! 

It seems there is hope for the future, though: 

Scientists are in the process of making natural and economical hair dyes based on DOPA that might use atmospheric oxygen to create basic colors. How cool is that?

What If You Leave It On Too Long?

Tick-tock! It’s rinsing o’clock! 

If you forgot to rinse on time, your scalp will be a little irritated and have a strong smell that can give you a headache. The hair can become fragile, dry, and brittle from the strong and overdue reaction of strong chemicals. 

Take note: 

We know you might try to be gentle with your hair, but be careful if using hair conditioner to dilute the dye – it can cause uneven coloring when not properly used and left in too long!

You may feel the way your hair will look, but nothing more serious will happen!

Learn More: How To Dilute Hair Dye?

What Happens If You Leave Hair Dye In Too Long – Conclusion

You’ve probably got used to doing all sorts of new things yourself – especially this year, during the lockdown. Even though being your own colorist is suitable for the budget, it may not be so good for your hair!

Since many factors are affecting the possible outcome – including your natural pigment’s color, the state of your protective cuticle, your previous coloring choices, and the dye you’ve just used, the last thing you need is to wonder:

What happens if you leave hair dye in too long?

If you’re here because of trouble, we recommend that you don’t panic. Nurture your cuticle with high-quality products for hydration, avoid hair coloring for a while – and go for a haircut if all else fails. 

Being a woman, you know there’s one golden rule: A woman that changes her hair is on her way to change her life!

So, maybe this accident can predict something good!

Related Read: How Long Does It Take To Dye Hair? An Hour Or More?