Can heat damaged hair be reversed?

Hair strands start to split at the ends where the hair is oldest and has experienced the most damage, but those splits can move up the hair shaft splitting multiple times, making the damage worse.

Because the hair has lost its elasticity, the strands are more susceptible to breakage. When the hair becomes too weak, the ends will snap off, leaving you with flyaways.

The best way to deal with heat damaged hair is prevention. However, if your hair is currently experiencing heat damage, there are steps you can take to manage it.

Heat damaged hair: causes, treatments, and prevention

After using hot tools on a regular basis, you may notice that your hair isn't as shiny, soft, and full as it once was. You may also notice more split ends or an excess of strands going down the drain each time you shower. These are all symptoms of heat damaged hair.

Heat damaged hair occurs when you blow dry, flat iron, or curl your hair at the highest temperature settings over an extended period of time. Most hot tools reach temperatures of more than 400°F, but this is misleading. Most hair can't handle such high heat, and heat damage can affect all types of hair from pin straight to tightly curled.

To test for heat damaged hair, pull a strand of hair from your head after you shower so it's wet. Carefully pull the strand from both ends. If the hair stretches approximately one-third before returning to its normal length, then your hair might be dry but has not been damaged. If the strand only stretches a small amount, doesn't stretch at all, or breaks when you stretch it, then you're dealing with heat damaged hair.

According to L’Oréal, there are three levels of damaged hair. Level one damage includes lifted cuticles that create a jagged appearance, but the cortex is not completely exposed. Level one hair is slightly less shiny and is thinner at the ends.

Level two hair has experienced abrasions to the cuticles, which means the cortex below has been exposed. When the cortex is unprotected, it's more vulnerable to additional damage. Your hair color – natural or dyed – may fade, your hair feels rough, and you have split ends.

Level three is the most extreme damage. The cuticles are the most damaged at this level and parts of the cuticles may be missing completely. The cortex is unshielded, so it becomes weaker, and hair feels very rough and coarse, it's dull, it tangles and knots easily, and hair is breaking off.

How does heat damage hair?

High temperatures permanently alter the structure of the protein bonds in your hair. Each strand of hair is made up of a protein known as keratin that has a natural curve called the alpha helix. This is present in both curly hair and straight hair. 

When the keratin is heated to temperatures higher than 400°F, the alpha helix begins melting. Once the alpha helix is melted, the change is permanent, and your hair will retain the shape of the melted keratin bonds.

Once your hair starts growing past the follicle, it's made up of dead cells. Because of this, the cells can't adapt, and when they're changed, it's permanent. There are no active cells that can be sent in to repair the damage.

The damage done to your hair is cumulative. The chances of you experiencing heat damaged hair after one blow dry or one straightening session are slim. However, using hot tools at high temperatures on a regular basis prolongs the changes to the protein bonds and moisture levels of each strand. Eventually, those bonds are broken, and hair becomes hydrated in a way that can't be fixed. If you continue using hot tools, the damage progresses as well.

To understand the extent of the damage to your hair, consider the following: 

• Have you applied chemical treatments like perms or relaxers to your hair?
• Do you rub your hair with a towel after you shower?
• Do you bleach or color your hair often?
• Do you skip moisturizing products post-shower?
• Do you spend a lot of time outdoors in the sun?
• Do you tend to brush your hair aggressively to work through knots?

If you've answered yes to any or all of these questions, then your hair might have been further damaged by environmental or mechanical factors in addition to heat.

9 Signs of heat damaged hair

As we've noted, damaged hair repair isn't possible because the protein bonds and cuticles have been permanently altered. Instead, the focus should be on maintaining hair to prevent further damage.

If your hair is severely damaged, the most extreme solution is to cut it off and start fresh. Depending on how high up the strands the damage goes, this could be less than an inch to several inches. Cutting your hair is the only way to completely remove the damage.

You might not be ready for such drastic measures yet. There are heat damaged hair treatment options you can try to minimize the look and feel of the damage and to keep your hair as strong as possible.

It's recommended that you get regular trims to manage and remove split ends. This gets rid of the most damaged parts of your hair, and it helps prevent the splits from moving further up the strands.

Try to let your hair air dry whenever possible. The continued use of hot tools can exacerbate the damage, so while you're managing the situation, it's helpful to avoid using the blow dryer, curling iron, and or flat iron as much as possible.

If you do use your hot tools, try them on lower heat settings and when possible, at a temperature between 200°F to 300°F. Before use, apply a heat protectant product to help minimize further damage.

Switch to moisturizing or damage-repairing shampoos and conditioners and choose ones that are free of sulfates and parabens. After showering, apply products that help rehydrate your hair, such as argan or jojoba oil and leave-in conditioners.

Heat damaged hair treatments