Do Heat Protectants Actually Shield Your Hair From Damage?

Mackenzie Dunn
·4-min read

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Despite what you may have heard, people with dark skin need to wear sunscreen, and shaving your hair won’t make it grow back thicker. In Myth Busters, we debunk common beauty misconceptions and set the record straight.

From flat irons to curling irons to your everyday blow dryer, styling your hair often means enlisting the help of scorching hot tools. By heating up the hair and weakening the hydrogen bonds that form between keratin proteins in the cortex of each strand, hot tools allow you to manipulate the hair's shape to your desired look.

However, as effective as hot tools are, the heat can damage the hair if not used correctly. One study on flat irons found that thermally stressing the hair led to a significant increase in hair breakage, which is why professionals and novices often turn to heat protectants before styling their hair.

But how effective are heat protectants? What do they do, and are they necessary for shielding hair from heat? To find out, we talked to two professional stylists to get the scoop on whether or not heat protectants are actually necessary.

What are heat protectants?

“Heat protectants create a barrier between the hair and the hot tool,” explains celebrity hairstylist Justine Marjan. They come in the forms of spritzes, aerosol sprays, and serums and are usually applied onto hair before styling it with any kind of heat-conducting tool.

How do heat protectants work?

Marjan tells us that many of these products are silicone-based. Silicones have low thermal conductivities so that when they’re coating your hair fibers, they slowly transfer the heat from the tool to the hair shaft to prevent overheating. When the hair heats up too suddenly, it can cause what’s known as “bubble hair,” which can induce water bubbles that become trapped inside your hair and end up damaging the shaft by "bubbling up" underneath. This can make strands feel dry and rough to the touch. Heating the hair more gently and evenly causes less damage to the hair, making it smooth, shiny, and healthier all around.

Other common heat-protecting ingredients include PVP/DMAPA acrylates copolymer, quaternium-70, and hydrolyzed wheat protein, but they all work in the same way. The goal of any heat protectant is to slow down the heat conduction from your hot tool and distribute it more evenly on the hair. Additionally, quality heat protectants often contain humectants to help preserve moisture as well as natural oils to protect and seal the hair's cuticle.

Are heat protectants necessary?

This depends on who you ask. Senada Ceka, a New York-based hairstylist, believes that heat protectants are an integral part of a healthy haircare routine. “I recommend them to all my clients,” she tells us. “I tell my clients to think of them as sunblock for their hair.” According to her, you especially don’t want to skip out on heat protectants if your hair is fine, bleached, or damaged as the heat will make it even more prone to breakage.

However, Marjan says that some hot tool brands—like GHD, for example—use revolutionary technology that limits damage by providing optimal, even heat—without the need for a heat protectant. “I usually don't worry about using a heat protectant when I am styling with GHD hot tools,” says Majan. “They only heat up to 365 degrees, which is the ideal temperature to style the hair without blowing out the cuticle and causing damage that can cause hair color to fade [and hair to] frizz and break.” According to her, it's a myth that the hotter the iron, the better they will work: “365 degrees is called the glass transition phase and is the same temperature used to melt and reshape glass without it breaking. The same idea can be applied to styling hair,” she says.

Additionally, heat protectants can only shield the hair so much. According to LabMuffin.com, a beauty research site, even the best results only show about 50% heat protection at most—and most don't offer broad protection from other threats, such as UV rays or pollutants in the air. Plus, Marjan points out that many of the most common heat protectants, which contain silicone, can weigh down finer hair types, making it more difficult to achieve a look with maximum volume.

If you want to be on the safe side, it doesn't hurt to spritz on a heat protectant before grabbing your favorite hot tool, but you may also be able to do without it by investing in high-quality tools that are specifically designed to distribute even heat. So, when it comes to the final verdict on this one, it's totally your call.