Do I Need a Heat Protectant?

Yes. The American Academy of Dermatology's guidance on healthy hair is to use low or medium heat settings and a product to protect your hair from the heat. It is one of the few points where a professional body is explicit about this, and it is worth taking at face value.

The rest of this page is about what that product actually does, because the marketing around the category oversells it in a specific and unhelpful way.

What a heat protectant does

• Slows heat transfer into the fiber. A film on the outside of the hair means the strand takes longer to reach the temperature of the tool, so less of the exposure lands on the keratin.
• Reduces moisture loss during styling. Rapid water loss from the cortex is part of what makes heat-styled hair brittle.
• Reduces friction, which matters more than people expect — a brush or a plate dragging on dry hair lifts cuticle mechanically, independently of any heat.
• Smooths the cuticle cosmetically, which is why hair looks shinier immediately after using one. That part is appearance rather than protection.

What it does not do

• It does not make wet-hair ironing acceptable. Wet keratin denatures between 120C and 150C. No film changes that.
• It does not repair existing damage. Nothing does. See preventing heat damage.
• It does not have a measurable SPF-style rating. There is no standardized scale for heat protection, so claims like "protects up to 450F" are not comparable between brands the way an SPF number is.
• It does not replace lowering the temperature. The AAD recommends low or medium heat AND a protectant. Both, not either.

How to use one so it works

1. 1Apply to damp hair, before drying — not to dry hair immediately before ironing. The drying stage is heat exposure too, and it is the stage most people leave unprotected.
2. 2Distribute it properly. Comb it through. A protectant sitting on the top layer protects the top layer.
3. 3Focus on the mid-lengths and ends. They are older, more damaged and get more tool contact than the roots do.
4. 4Do not soak the hair. More product does not mean more protection, and excess weighs fine hair down and can sizzle on a hot plate.
5. 5Let it dry before an iron touches it. Applying a wet product and immediately ironing puts you back in the wet-hair scenario, which is the thing you were avoiding.

Which pairs with which tool

A protectant matters most where contact heat is highest, which means the tools rather than the sprays are what to prioritize. In rough order of exposure: flat irons and curling irons first, then contact brushes, then dryers.

• [Flat irons](/straighteners) — highest exposure on this site. 330F to 450F in direct contact. Always use one.
• [Curling irons](/curling-irons) — same order of contact heat, similar durations.
• [Blow-dry brushes](/blow-dry-brushes) — contact heat, but far lower. Worth using.
• [Hair dryers](/hair-dryers) — no contact, and published maximums of 212F to 230F on the tools that publish anything. Worth using, and the lowest priority of the four.

If you only do one of the things on this page, apply a protectant before the drying stage rather than before the ironing stage — that is where most people leave the biggest gap.