It’s no secret that HeatBounce has changed the heat protection game, forever. Heat styling has rapidly evolved in recent years with faster tools, dynamic temperatures, and more frequent consumer use. But the tech to protect hair hadn’t kept up. Most heat protectants on the market rely on surface coatings that act like rubber raincoats: heavy, temporary, and ineffective where it matters most to hair’s health. 

K18 saw the need for something smarter, so (as always) we turned to biology for inspiration. Patented resilicore™ heat-shielding technology dynamically activates with heat to reinforce the inner structure of the hair fiber like a flexible shield from outer cuticle to inner cortex*—just like nature intended.

But how? Let’s back up.

a biology-first solution 

Scientists have long explored resilient proteins found in nature as a source of inspiration and awe. The natural world has a way of showing off evolution's most refined engineering solutions, the plants, animals, and organisms built to absorb tremendous stress from the environment (think: cacti thriving in 100°F deserts) while finding a way to flourish even under the most extreme conditions. 

So we asked: How does nature intelligently defend against heat, and how can we apply that to hair? 

the heat protection paradox

For decades, heat protection has stopped at the surface level—hair’s outer cuticle. The way most heat protectants work is by creating a barrier that sits on top of hair like a protective coating, offering the promise of defending against heat styling damage, but still leaving hair susceptible to dullness, breakage, and frizz over time.

There's a fundamental mismatch between where these products work and where heat damage actually occurs. If heat goes deep, but protection stays shallow, your hair ends up paying the price.

what is heat damage? 

When you apply high heat from styling tools, that energy travels deep into the hair's structure, penetrating past the outer cuticle and reaching the cortex (the innermost layer of hair) responsible for its structural integrity.

Inside the cortex, this heat causes keratin proteins (the building blocks responsible for hair's strength and elasticity) to denature—a fancy way of saying the proteins lose their natural structure and function.

The result? Hair that loses its strength and resilience, leaving it dry, lackluster, or frizzy—just a few of the visible signs that hair’s internal structure has been compromised.

the problem with traditional heat protectants 

Most heat protectants rely on silicone-based ingredients with large molecular structures. These molecules are too big to penetrate through the hair's cuticle and reach the cortex, where heat damage occurs and deeper protection is needed.

Instead, they form a coating on the hair's surface, creating a barrier that may deflect some heat but can't protect what's happening underneath.

Surface-only protection fails to prevent keratin protein denaturing under heat stress because the thermal energy travels right past the protective coating and into the hair's vulnerable interior. It's the molecular equivalent of trying to protect a building's foundation by only painting the exterior walls - the protection is in the wrong place entirely.

Adding to this fundamental efficacy issue, today's consumers are increasingly rejecting silicone-heavy formulations due to concerns about product buildup and environmental impact. Many people find that traditional heat protectants leave their hair feeling weighed down or coated, requiring frequent washing to remove residue.

patented resilicore™ technology protects from within

Enter patented resilicore™ heat-shielding technology—a biomimetic innovation inspired by a highly resilient protein found in nature, best known for its ability to stretch more than three times its original length and bounce back hundreds of millions of times while maintaining its structural integrity.

resilicore™ takes inspiration from nature’s astonishing protective properties, and was recreated in the lab to apply these properties in a form designed to work where all hair types are the same—the molecular level. 

The smaller, optimized molecule found in HeatBounce penetrates from hair's cuticle to cortex* and protects keratin proteins from heat damage. It provides internal structural protection while maintaining the weightless, conditioning benefits to make hair soft, shiny, and bouncy.