What Is Worse for Your Hair: A Curling Iron or a Straightener?

Avoid overexposure to heat.

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Styling your hair with heated tools such as curling irons and straighteners may give you the “just stepped out of a salon” look. However, you need to use those tools wisely or else your styling efforts may end up leading to fried-looking hair in the long run. Neither a curling iron nor a straightener is necessarily more damaging than the other. The factors that matter most are the quality of the tool, how frequently you use it and what you do to protect your hair from heat damage.

The Problem

Curling and straightening your hair can cause the topmost layer of each hair to lift. When this outer layer -- called the cuticle -- lifts, it releases moisture and causes your hair to become brittle, according to “Good Housekeeping” magazine. If you regularly use a curling iron or straightener, try testing your hair’s brittleness. Start by running a fingernail along an entire hair that has fallen or been removed from your scalp, much like you would curl a ribbon, recommends Cheri McMaster, a scientist for Pantene. Toss that strand of hair into a clear glass filled with water and wait for it to uncurl. If it doesn’t uncurl, chances are it is no longer as elastic as it should be.

Curling Iron Drawbacks

One factor that could make a curling iron extra damaging to your hair is the iron clamp. Avoid using it unless you plan to curl the ends, recommends CBS News. Regularly wrapping all your tresses in a hot clamp is bound to cause extra-dry, frizzy, dead hair. To reduce your risk of heat damage, separate your hair into sections that are 1 to 2 inches thick and use a curling iron that is ceramic and has a wide barrel. Limit curling time to no more than 10 to 15 seconds per section.

Risks of Straighteners

Having perfectly straight hair may be sleek and sexy, but having straight hair with unruly, broken pieces sticking out is not. Overuse of a straightener can lead to unwanted damage in the same way that overexposure to a curling iron can destroy healthy hair. To reduce your risk of losing too much moisture, stick with a ceramic iron, carefully read the instructions on the iron’s box -- generally about five seconds of heat per section -- and only use the tool about once a week, recommends “Allure” magazine. If you use a chemical straightener rather than a straightening iron, switch to a keratin treatment to keep your strands coated and to avoid aggravating the middle layer.


If you choose to use a curler or straightener, keep some damage-control methods up your sleeve. Ditch any heat-styling device that is more than five years old to increase the likelihood that the temperature gauge is still intact, recommends “Good Housekeeping.” To keep your hair as shielded as possible, apply a special heat-protectant serum or spray that has dimethicone in it. The compound dimethicone melts and is a barrier between your hair and some of the high temps you’ll be exposing it to. Also, use regular conditioner on your hair every day and deep condition once per week with a hot-oil treatment or a hair mask.

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