The One Hair Product Experts Agree Everyone Should Be Using For Stronger, Thicker, Healthier Hair (2025)

Using a 400-degree flat iron without a heat protectant is asking for trouble. That's the point of these products—they create a crucial buffer between your hair and all that sizzling heat so you can still nail your favorite style, whether that's a sleek blowout or beachy waves.

But here’s the twist: Even if your go-to look is au-naturale and your hair dryer is gathering dust in a drawer, you should still be using a heat protectant every single day. A generous spritz doesn't just shield hair from extreme temperatures—it also defends against pollution and other environmental stressors that quietly compromise your hair’s strength and shine over time, says Gregorio Ruggeri, who is a trichologist—that's someone who specializes in the study and treatment of hair and scalp disorders—for OGX.

Meet the experts: Gregorio Ruggeri is a trichologist for OGX. Valerie Aparovich is a biochemist and science team lead at OnSkin.

But what if you've never picked up a bottle of the stuff in your life? We've got you covered: Here, cosmetic chemists and hair experts break down exactly how these products work, what ingredients to look for, and what to know before adding *apply heat protectant* to your daily to-do list.

The science of how heat protectants work.

These products are typically categorized as styling products, since their primary job is to create a barrier between your hair and hot tools like blowdryers, straighteners, and curling irons. Ingredients like silicones (such as dimethicone) and polymers (like polyquaterniums and acrylates) form a smooth, flexible coating along the hair shaft, creating a physical barrier that helps distribute heat more evenly and promotes better moisture retention across the hair’s surface, says Valerie Aparovich, biochemist and science team lead at OnSkin.

But that invisible barrier can do more than merely shield against scorching temps. "Many heat protectant formulas also include proteins like milk protein, elastin, or keratin, as well as polysaccharides, which enhance the film’s ability to envelop and protect the hair," says Aparovich. And once this protective film binds to your strands, it not only seals the cuticle to reduce moisture loss, dryness, and breakage, but also protects against airborne pollutants like dust, pollution, and smoke, helping to the minimize oxidative stress that can compromise hair over time.

Many of these products also contain UV filters like benzophenone-4 or octocrylene to also protect against the sun's damaging rays, though research on their efficacy as it relates to hair is still evolving, says Aparovich, pointing to limited and inconsistent studies from 2006 and 2023.

Here's what to look for in a heat protectant.

It's important to note that not all heat protectants are created equal. When shopping, keep these factors in mind:

Ingredients

Truly effective formulas blend traditional film-formers (those silicones and polymers) with nourishing ingredients like proteins, plant extracts, and oils, says Aparovich, who recommends looking for products that include botanical antioxidants like agave leaf extract, jackfruit extract, or argan oil to help neutralize free radicals from UV exposure and pollution.

Just be careful to avoid heavy, silicone-loaded formulas that lack other good-for-hair ingredients—they can coat locks without delivering meaningful conditioning benefits.

Formulation

The product's format matters, too. Lightweight sprays are great for thick or oily hair and warm weather, while creams and serums better serve dry, damaged, or frizz-prone hair—especially in colder or more humid conditions.

Handle With Care: The Right Way to Use Heat Protectant

When used properly, daily application of a quality heat protectant is generally safe—and beneficial—for most hair types, says Aparovich. For best results, avoid applying heat protectants directly to the scalp or close to the hair root. Sticking to the mid-lengths and ends will help avoid any sticky or oily residue, plus minimize scalp irritation and congestion.

Don't be too heavy-handed, either. Overusing products rich in non-water soluble silicones (dimethicone, cetearyl methicone, cetyl dimethicone, stearyl dimethicone, and dimethiconol) can cause the kind of buildup that weighs down strands, decreases natural volume, and even leaves the hair sticky and greasy.

To that point: "Washing the hair regularly with a clarifying shampoo is crucial to minimize keep the strands fresh and bouncy," says Aparovich. The catch-22? Over-clarifying—especially with sulfate-heavy formulas—can dry out and weaken hair, she adds, noting this is especially true for those with dry and color-treated hair. Stick to once a week.

And finally, remember that while heat protectants are incredibly helpful tools to have in your beauty arsenal, they don't make hair invincible. Limiting mechanical stress (brushing too aggressively, tight hairstyles, rough towel drying), using gentle cleansing routines, and embracing sun-safe habits (like wearing a hat or seeking out shade) all contribute to healthier hair over time.

Now that's hot.