What Are Hot Roots? (How to Fix & Prevent Them)

Let’s talk about hot roots!

You wash out your hair color, towel dry, take one look in the mirror, and there they are. Brassy, orange, way-too-bright roots that look nothing like the rest of your hair.

Hot roots. The most common at-home hair color mishap there is.

…and you can’t even hide them with all the glitter in the world.

I fielded questions about this constantly when I worked at Sally Beauty Supply, and later in the salon when clients came in after a DIY color job gone sideways. The good news is that hot roots are completely fixable, and once you understand what causes them, they’re just as easy to prevent.

Here’s everything you need to know.

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What Are Hot Roots?

Hot roots are exactly what they sound like: roots that come out warmer, brighter, or brassier than the rest of your hair after a color service. They usually show up as a stripe of orange color right at the scalp, while the lengths and ends look completely different.

They’re called “hot” because of the warm, fiery tones involved. And they’re one of those problems that’s impossible to ignore once you see them.

Hot roots can happen to anyone coloring at home, but they’re also something I saw in the salon when formulas weren’t dialed in correctly. Understanding why they happen is the first step to fixing and avoiding them.

What Causes Hot Roots?

There are three main scenarios that cause hot roots, and honestly, most at-home color mishaps come down to at least one of them.

#1. Body Heat from Your Scalp

Your scalp emits heat constantly. That heat causes hair color to process faster and lift more at the roots than it does at the lengths and ends. So even if you apply the exact same color from root to tip, the roots will often come out lighter or warmer than the rest of your hair simply because of the extra heat at the scalp.

This is the most common cause of hot roots and the one that catches most people off guard. You did everything right, followed the instructions, and your roots still came out brassy. Scalp heat is almost always the culprit.

#2. Virgin Roots vs. Previously Colored Hair

Your outgrowth is virgin hair. It has never been colored, which means it reacts completely differently to dye than the previously colored hair right next to it.

Virgin hair lifts more easily and more evenly than hair that already has color molecules packed into the shaft. So when you apply color from roots to ends, your virgin roots can lift several levels while your previously colored lengths barely budge. The result is two completely different tones on the same head of hair.

#3. Using the Wrong Formula or Level

If you’re touching up roots with a color that’s a different level or tone than what’s already on your hair, you’re going to get two different results. Even a one-level difference can be noticeable, especially on lighter hair.

For example: your hair is a level 10 ultra blonde, but you touch up your roots with a level 8 golden blonde. Those roots are going to look noticeably darker and warmer than the rest of your hair.

How to Fix Hot Roots at Home

If you already have hot roots, here’s how to address them depending on how severe they are.

Option #1: Purple or Blue Shampoo

This is your first line of defense for mild brassiness.

Purple shampoo neutralizes yellow tones and blue shampoo neutralizes orange tones. If your roots are only slightly warm, a few washes with the right toning shampoo can calm them down significantly without any additional color.

Purple shampoo works best for blonde hair with yellow or brassy roots. On the other hand, blue shampoo is the better call for darker blonde or brunette hair with orange tones.

Use it two to three times a week and leave it on for 3-5 minutes before rinsing. You should see a difference within a week.

✅ Best for: Mild brassiness, slightly warm roots on blonde hair

⚠️ Won’t fix: Significantly orange or red roots that are several levels off from the rest of your hair

Option #2: Toner

If purple shampoo isn’t cutting it, a hair toner is the next step. Toners are semi-permanent colors that deposit a cool or neutral tone to neutralize unwanted warmth.

They don’t lift, they just deposit, so they work best when your roots are close to the right level but just too warm.

Apply the toner to only the root area and smudge it slightly into the lengths to blend the line of demarcation. Don’t pull it all the way through unless your lengths need toning too.

Wella T18 is a reliable at-home toner for blonde hair. For warmer, more orange tones, Wella T14 is a better choice.

Read more about how to use a hair toner for brassiness here!

✅ Best for: Roots that are the right level but too warm or brassy

⚠️ Won’t fix: Roots that are significantly lighter or darker than the rest of your hair since that’s a level issue, not a tone issue

Option #3: Root Concealer

If you need a fast fix before your next color appointment, a root concealer spray or powder is a temporary solution that buys you time.

It’s not a permanent fix, but it works in a pinch.

Color Wow Root Cover Up is the most widely recommended option and comes in a range of shades. It washes out with shampoo and doesn’t transfer onto pillowcases or clothing once dry.

✅ Best for: Buying time between appointments, covering roots for a specific event

⚠️ Not a permanent fix: This is a bandaid, not a solution

Option #4: Fix Hot Roots With a Darker Color

If your roots are significantly off and toning isn’t enough, re-coloring with a slightly darker shade is often the most effective fix. The goal is to bring the roots down to match the rest of your hair rather than trying to lift the lengths up to match the roots.

Wait at least two weeks before applying any more color to give your hair a break.

When you do re-color, apply only to the root area, not root to tip. Choose a shade that’s one level darker or cooler than your target color to account for the extra lift from scalp heat. That way when it processes, it lands right where you want it.

More on how to apply it correctly in the prevention section below.

✅ Best for: Hot roots that are several levels or tones lighter than the rest of your hair

Blonde Hot Roots: A Special Case

Hot roots on blonde hair deserve their own mention because they’re the most common scenario and the most visible.

When you’re working with blonde hair, even a small amount of warmth at the roots stands out dramatically against the lighter lengths.

If you have blonde hair and your roots came out orange or brassy, here’s the fastest fix:

• Mild yellow or gold roots: Purple shampoo used 2-3 times a week will neutralize the warmth within a week or two.
• Orange or copper roots: Purple shampoo won’t be strong enough. Go straight to a blue shampoo or a toner like Wella T14, which is specifically formulated to neutralize orange tones.
• Roots that are significantly lighter than the rest of your blonde: This is a level issue, not a tone issue. A toner won’t fix it. You’ll need to re-color the roots with a slightly darker blonde shade as outlined in Option 4 above.

The key with blonde hot roots is identifying whether the problem is the tone (too warm) or the level (too light). The fix is completely different depending on which one you’re dealing with.

How to Fix Hot Roots at the Salon

Sometimes the smartest move is to put down the box color and book an appointment. There’s no shame in it.

Color correction is one of the most technically complex services in a salon… but a good colorist can fix you up in one appointment vs. several failed attempts at home.

When to call a professional:

• Your roots are significantly lighter or warmer than the rest of your hair and toning hasn’t worked
• You have visible color banding, a halo effect, or an obvious line of demarcation
• You’ve already colored over the problem and made it worse
• Your hair is damaged, breaking, or over-processed
• You’ve had multiple box color applications and the color is unpredictable

What a colorist will do: Depending on how severe the hot roots are, your stylist has a few options. A root gloss or toner applied specifically to the root area can neutralize brassiness quickly and affordably.

For more significant level differences, a targeted color application on the roots alone brings them back in line with the lengths.

If the contrast is dramatic, a shadow root or root smudge technique blends the two tones together seamlessly so the difference becomes invisible.

Be honest with your stylist about everything you’ve done to your hair at home. The more information they have, the better the result. A good colorist isn’t there to judge you. They just need the full picture to formulate correctly.

How to Prevent Hot Roots Next Time

Prevention is always easier than fixing the problem after the fact. Here’s what to do differently next time.

⏱️ Apply color to the roots last, not first. When going lighter, apply color to the lengths and ends first and leave the roots for the last 15-20 minutes of processing. This accounts for the extra heat at the scalp and gives the lengths more processing time to catch up.

🎨 Use a shade slightly darker or cooler at the roots. If you know your roots tend to go warm, formulate the root color one shade darker or cooler than what you’re putting on the lengths. The extra scalp heat will bring it up to match.

🚫 Don’t overlap onto previously colored hair. When touching up outgrowth, apply color to the new growth only. Pulling color through the lengths every time you color causes color buildup, uneven results, and eventually damage.

🔍 Match the tone at the roots to the tone on the lengths. This sounds obvious but it’s where a lot of at-home color goes wrong. If your hair has a cool ash tone, use a cool ash formula at the roots. Using a neutral or warm formula on cool-toned hair will always result in a mismatch.

💧 Use a lower developer at the scalp. If you’re doing an all-over color and want to minimize the risk of hot roots, use 20 volume developer at the roots instead of 30. The lift will be slightly less dramatic, which helps keep things even.

What About Intentional Dark Roots? The Shadow Root Trend

Not all visible roots are a mishap.

The shadow root trend is exactly what it sounds like: intentionally keeping the roots slightly darker than the rest of the hair. It looks natural, grows out beautifully, and requires far less upkeep than a traditional all-over color.

The technique is called root smudging or shadow rooting. A colorist applies a slightly darker formula to the root area and blends it softly into the lighter lengths.

No harsh lines, no demarcation. Just a seamless, effortless transition.

The difference between hot roots and a shadow root comes down to two things: intention and execution. Hot roots are uneven and brassy. A shadow root is deliberate, blended, and beautiful.

FAQ

Final Thoughts

Hot roots are frustrating, but they’re also one of the most fixable hair color problems out there. But, fortunately, you have real options.

And next time you color, a few small adjustments to your application technique will make all the difference.

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! 👇🏼👇🏼👇🏼

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