When you’re dealing with hot roots, it’s helpful to understand keratinization. When new hair grows from the scalp, it takes about a month to fully “harden” once it emerges from the hair follicle. Most people’s hair grows about ½ – 1 inch per month (this figure can vary based on individual hair growth rates). Hot roots appear at that point of new hair growth.

Newer hair is softer and doesn’t have as much hardened keratin as older hair, so dyes and bleach can penetrate more quickly into the hair shaft. When coloring agents are left on new hair for the same amount of time as old hair, they’ll inevitably turn out lighter. Hot roots!

‘I Dyed My Hair and Roots Are Lighter’ – Here’s A Quick Fix

How to Avoid Hot Roots

Most salon professionals believe the best way to avoid hot roots is to minimize errors in the timing and formulation of hair color applications.

When people dye their hair at home, they tend to buy one box of color and apply it to the entire head of hair, from the roots to the ends. The problem is, hair that’s growing out from the scalp is virgin, and therefore, it absorbs the dye faster than the older hair. That’s why the hair at the root level can often be lighter or brassier.

To combat this problem when you apply a color treatment, always dye the full length of your hair first, and save the ½ – 1-inch new growth area until the end. This technique gives the older hair more time to “catch up” to the newer hair that’s absorbing the coloring agent more quickly.

Another way to avoid hot roots is to use two different color formulations on your hair. If you choose to go this route, select a slightly darker shade for the regrowth hair near the roots.

Bleaching Hot Roots

Always apply bleach to the lengths of your hair first, just as you do when using a permanent dye. Hair lengths are older and cooler than root hair that’s located closer to the scalp, so they take more time to lighten.