Expert Q&A: How to Prevent Hair Damage
Zoe D. Draelos, MD, Explains How Hair Dryers and Chemicals Can Damage Your Hair
By Charlene Laino
WebMD Health News
Reviewed by Laura J. Martin, MD
woman flat ironing hair

Feb. 7, 2011 (New Orleans) -- Dyes and blow dryers may help make you stylish in the short term, but over time, harsh chemicals and heated styling devices can damage your hair, an expert says.
At the annual meeting of the American Academy of Dermatology, Zoe D. Draelos, MD, consulting professor at Duke University School of Medicine in Durham, N.C., discussed the most common sources of hair damage and offered tips to maintain a healthy, lustrous head of hair.

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Are chemical dyes bad for the hair?

Chemical damage is one of the most common culprits of hair damage, as processed hair loses its natural moisturizers and the protective lipid layer of fat on the outside of the cuticle -- responsible for making the hair shiny -- is removed. The result: dried-out, dull, frizzy hair.
What's the best way to combat chemical damage?

Use conditioning shampoos and conditioners regularly to improve the appearance of frizzy hair. Two-in-one shampoos that remove oil from the scalp, clean the hair, and then condition the hair in the rinse phase also are good choices.

Look for shampoos, conditioners, sprays, and creams containing dimethicone, which has been shown to decrease static electricity, increase shine, and improve manageability.

Hair serums, which are rubbed through the length of the hair, may also help.

Of course the best option is to stop dyeing your hair. If you do dye, choose a shade that's within three shades of you natural color. Dyeing hair darker, rather than lighter, also generally is less damaging.
Can the sun damage hair?

Hair can get tanned and damaged, just like skin. Exposure to ultraviolet light from the sun or a tanning booth weakens the hair structurally, resulting in hair breakage and loss.

The best protection is a hat or umbrella, though conditioners that contain a sunscreen can help. Just be sure to reapply after each shampoo.

Grey hair is most subject to damage from the sun, followed by blonde hair. If your hair is grey and you’re going to be out in the sun a lot without a hat, you may want to consider dyeing it dark; it's a trade-off, but damage from the sun is worse in this case than damage from the dye.
Can blow-drying my hair result in damage?

Yes. Water in hair is what makes it flexible. Heating appliances boil the water within the hair shaft, creating escaping steam. Hair bubbles form on the hair shaft, creating a loss of cuticle. Signs of heat damage include hair that smells burned, has frizzy ends, and breaks easily.
How can I dry my hair without damaging it?

Allow it to air dry, when possible. If you have to use a hairdryer, start out on the lowest heat setting first and gradually increase it.

Moisturizing the hair regularly will help the appearance of heat-damaged hair to some degree, but hair damaged by heat cannot be repaired. The affected hair will need to be cut off and allowed to regrow as healthy hair.