If you’ve ever indulged in a little at-home hair color, you’ve likely run into hot roots at one point or another.
You know what I’m talking about… like when you wash out your hair color, and your roots are a nice shade of super-bright brassy… while the rest of your hair is that perfect tone.
…and you can’t even hide them with all the glitter in the world.
These, my friend, are called “hot roots,” and they’re generally frowned upon in the hair industry.
But then you mix in Billie Eilish and a world-wide lockdown, and you’ve got yourself a new hair color trend.
So what’s the deal? Are they hot or not?
Let’s talk about what causes the undesirable look, how to avoid and/or fix it, and how you can get trendy roots at home if you wanted to…
💡TIP: Pin this article to your Hair Color board on Pinterest so you can always come back to it when you need to! 👇🏼👇🏼👇🏼
*This post contains affiliate links meaning that if you make a purchase after clicking the link, I earn a small commission at no additional cost to you. This helps me provide the best possible content on this site for free. Keep in mind that I only link to quality products that I use myself and feel would be beneficial for my readers.
Please read my full affiliate disclosure for more information.
What Are Hot Roots & Where Do They Come From?
Let’s start by talking about virgin hair… aka hair that has never been colored. Never. Not even one tiny bit.
It reacts completely differently to color than hair that has been previously colored.
And as you probably concluded, your outgrowth consists of virgin hair. And it reacts completely differently to the dye than the previously colored hair right next to it.
Are you keeping up? Good… because here’s another thing we need to throw into the equation: your scalp emits body heat, which makes hair color process faster and lighter than the rest of your hair.
Last but not least, if there is a contrast between the outgrowth and the previously colored hair (like blonde hair with dark brown roots), you’ll have to use different color formulations on each section.
For example, you’d have to lighten the dark roots without lightening the blonde hair, etc.
So as you can imagine, all of this is the perfect recipe for disaster.
What Causes Hot Roots?
Typically, when someone colors their hair, it’s because they have outgrowth they want to cover… which means that they’ll be starting with two different base colors.
If the previously colored hair is darker than the new target color, you’ll have to lighten it before adding the new color. In other words, you can’t lighten hair color with more hair color… it has to be lifted with bleach or color stripper (see The Golden Rule of Hair Color for more info on this phenomenon).
If you don’t lift the previously colored hair with bleach first, only the roots will get lighter, while you just add more pigment to the previously colored hair… which can actually make it darker.
Let’s sum that all up with an example: Let’s say that you’re naturally dirty blonde, but dyed your hair medium brown. Then, let’s pretend that one month later, you put a golden blonde color all over your whole head. The roots would turn perfectly golden blonde, but the medium brown would stay brown.
On the contrary, if you use a different level, shade, or base color on the roots than the rest of your hair, you’ll end up with two different shades.
For instance, let’s say you already have a level 10 ultra-blonde on your hair, but you touch up your roots with a level 8 golden blonde. This will result in two different colors.
Especially if your hair is already lighter than your roots.
Last but not least, if you apply a lighter color from scalp to ends, the body heat makes the color lift more at your scalp, resulting in a different level.
To prevent this from happening, start by applying color 1″ away from the scalp. When the hair is halfway-through processing, apply the color to the roots. But don’t worry about doing this when going darker… it only needs to be done when going lighter.
So many different scenarios, right? Remember: this is why hair colorists make the big bucks.
How to Prevent It From Happening
Of course, the absolute best advice I can give you is always to get your hair done by a trained professional. They’ll be able to match the tone and level of your roots to the tone and level of the rest of your hair.
BUT… if you still want to give it a go, here’s what you’ll need to do:
- Like I previously mentioned, if you are going lighter on virgin hair, don’t apply color to the root area until the rest of the hair is 50% done processing.
- Likewise, you can always use a shade darker at the root area to prevent it from going lighter than the rest of your hair.
- If you have outgrowth and are going lighter all over, you can lighten your roots and freshen up the rest of your hair with a “color-balancing” pre-treatment. This will cause minimal damage while giving you a clean slate to work on. If your previously colored hair is super dark (like black or dark brown), you may need to bleach it first.
- You may need to formulate color or bleach differently for the outgrowth than the rest of your hair. For instance, it might be wise to use a lower-level developer on the outgrowth.
- When touching up outgrowth with the same color as the rest of your hair, make sure not to overlap the color onto the previously colored hair. This can cause a halo or color-banding effect.
- Also, when touching up regrowth, make sure to use the same tone as the previously colored hair.
Just remember that color isn’t a “one-size-fits-all” type thing. Every formulation is different for each unique situation.
How to Fix A Hair Color Mishap
So you ended up with a mishap… now what?
If your roots are super brassy, you may need to tone them down with a cooler color. Apply the toner to the line of demarcation and slightly smudge it into the rest of your hair.
You could also try purple shampoo to counteract yellow undertones.
The other option is to wait a day or two before applying a color that is one shade darker to the root area.
How To get Billie Eilish Hair
If you want to give yourself hot roots purposely, make sure to use a smudging technique, like this one by Gal Biller. This helps blend the color into the rest of your hair.
If you want bright colors like Billie Eilish, you may need to bleach out your root section first.
You can tone them down or color over them, but they usually don’t go away on their own. However, they may be less noticeable as your hair grows out.
Several things could cause this phenomenon to happen. That being said, the most common reason is that body heat from the scalp causes the hair to lift more in that section.
You can use a shade darker near the scalp or formulate the color differently for the hair near the scalp. You can also wait to apply color to the scalp area until the rest of the hair has processed 50%.
Since different things can cause this phenomenon to happen, different outcomes could occur. However, it usually looks like hair that’s lighter near the scalp (generally with brassy tones).
Dying your hair is typically more complicated than slapping on color and calling it a day. You have to formulate the color with love and have a plan of attack before you start.
While it’s always best to have a professional help you, it’s not impossible to come up with the correct color formulation at home.
With these tips and a little common sense, you’re sure to avoid the dreaded hot root dilemma.
Until next time,
► YOUR TURN: Have you ever ended up with hot roots? What did you do to get rid of them? Drop your thoughts in the comments section below! 👇🏼👇🏼👇🏼