The bottom line when it comes to heat styling? If it’s hot, it hurts. Whether your hair is short, long, thick, or fine, applying blow dryers or hot tools directly to your strands will always cause some level of damage. But for a lot of us, heat styling is a non-negotiable part of our routine, a way to express ourselves–and we’d never dream of telling you to give that up. 

Yes, hot tools are here to stay—and no, they aren’t the enemy. The real problem lies in the persistent myths that surround them, leading to more damage than necessary. For example, for a long time many of us have been led to believe that air drying is a more virtuous option than blow drying (not necessarily true!) or that heat damage only happens when you crank the temperature all the way up.

The truth is, heat styling doesn’t have to mean compromising your hair’s health if you know what you’re doing–and that starts with separating hard facts from hair fiction.

To help set the record straight, we asked Emma Cooban, K18’s senior hair fiber and measurement scientist, to debunk five of the most common heat styling myths. 

myth #1: low heat doesn’t damage hair

Fact: All heat damages hair—even at lower temps.

“Styling at lower temperatures (under 392°F on dry hair) can be less damaging than higher temperatures,” says Cooban, “But ‘less’ isn’t ‘none.’ Even at gentler settings, heat can weaken the structural proteins of the hair—especially if the hair already has some pre-existing damage from color, bleach, or chemical services.”

Heat damage is also cumulative, meaning even small amounts of exposure can add up over time. That’s why using a heat protectant like HeatBounce is essential for every heat style, including diffusing or blow drying—without exception.

myth #2: heat damage only affects the surface of the hair

Fact: Heat doesn’t just crack the surface—it denatures the cortex.

Sure, you’ll notice the frizz, split ends, and dullness when heat lifts and breaks the hair cuticle, but the real damage extends far deeper than you think. “Temperatures above 392°F start to denature proteins in the hair’s cortex (the very heart of the hair fiber), meaning they become weaker as they lose their strength and elasticity,” says Cooban. 

That’s why we made HeatBounce. Formulated with patented resilicore™ technology, it goes further than traditional heat protectants can reach to defend hair all the way to the cortex.

myth #3: hotter tools make styles last longer

Fact: Higher heat doesn’t equal more hold—just more harm.

Cranking up the temperature may speed up styling time, but it won’t lock in that look for longer. What it will do is amplify the damage—especially if you're not using adequate heat protection and are doing a service that is inherently more damaging, like a silk press. “Styling at high temps (again, above 392°F), rapidly leads to more hair damage,” says Cooban.

This is where HeatBounce really earns its name–bouncing away heat up to a scorching 450°F (aka grill-level hot) to keep hair protected, even under the most extreme conditions.

myth #4: thick hair doesn’t get damaged as easily

Fact: All hair types are vulnerable to heat damage.

“No texture is immune to thermal damage,” says Cooban, adding that in all hair types, the hair’s cortex is made up of chains of keratin proteins which provide hair with its core strength and elasticity. “High heat damages these proteins,” she says, “which means the structure of hair is weaker, and more prone to breakage.”

That’s why K18 takes a biology-first approach to protection and repair, working at the innermost layers of hair where all hair types are the same. So, no matter what your texture, HeatBounce (and everything else in our product lineup) will work for your hair.  

myth #5: you shouldn’t use hot tools every day

Fact: Daily heat use causes damage—unless you're protecting and repairing.

Even occasional heat styling can weaken hair if you’re not safeguarding it where it matters most. But daily? That’s a fast track to fragility. To cover your bases, Cooban recommends K18 molecular repair mask a few times a week to restore strength at the core, plus HeatBounce conditioning heat protectant to soften, detangle, and shield hair from temps up to 450°F every time you blow dry or reach for a hot tool. 

It’s high time we set the record straight on your straightener. The more you know, the better you can take care of your hair. So go ahead, turn on the heat (without the damage). 

*www.k18hair.com/disclaimers