How Does Hair Dye Damage Your Hair?

by Andrea Campbell ; Updated September 28, 2017

How Does Hair Dye Damage Your Hair?

Trouble for Hair?

Hair has been called "our crowning glory," but apparently women don't like their hair because more women are changing the color of their hair than ever before. But is this obsession with finding the perfect color bad for our hair? The answer is: It depends.

What's In It?

The three types of hair color --- permanent, semi-permanent and temporary --- all have chemicals in varying levels. The permanent colors are obviously meant to last longer and, according to the Food and Drug Administration, they are broken up into two categories: oxidation dye or progressive dyes.

The oxidation type becomes a dye after a chemical reaction with hair. The progressive type are dyes themselves but need additives to get to the desired shade; some of the chemicals used to do that are ammonia, soap and detergent, a conditioner and hydrogen peroxide. What you generally see in the box are a developer and an ammonia-based dye that are mixed together to form a cream.

What Happens to Hair?

The cream dye mixture makes the hair shaft swell to accept the color and process further. Certain ingredients that do this are metallic lead and bismuth citrate --- and in proscribed doses that are approved as safe. Our hair has keratin and it's the sulfur within that oxidizes with the chemicals, causing a color change.

Lesser Color Products

Another category of color -- semi-permanent and temporary color -- have coal tar (an antiquated way of saying "petroleum") that sticks to the hair shaft and leaves behind color. Inside this mixture are coal tar dyes, organic solvents --- salts or vegetable substances, gums, wetting agents called "surfactants" and conditioning ingredients.

Your Caveat

In your color box will be a pair of plastic gloves and a cap (optional), but there will generally be a cautionary warning. This protects the manufacturer, but it also protects you. There are two main instructions with this warning: to do a preliminary test on your skin before proceeding, and to refrain from trying to color eyelashes or eyebrows, which can cause blindness.

Problems Associated with Hair Dyes

Hair dyes have caused bad reactions among some people like redness, itchy or irritated skin, burning, hair loss and -- with an extreme allergic reaction -- facial swelling and labored breathing.

Long-Term Damage

The FDA has backed off of approving coal tar dyes; if the box has the patch test instructions, that's all it needs. The problem with continued use however, is that someone can develop an allergy later on in life.

Another problem to the hair emerges when women have their hair straightened and colored, too. Also, overuse of dyes, dye sitting too long to develop, and other variables can damage hair. This will typically mean breaks in the shaft of the hair.

Under a microscope, a hair is not smooth but appears to have scales. These are proteins called keratins, in three different layers. Most dye can penetrate the layers, causing hair to dry out, produce fly-aways and create breakage that makes for open spots in the scalp.

Most of these poor results are not permanent, however. If you stop the coloring, hair should grow back. And the outer layer --- the cuticle --- has the scales; so when it accepts conditioning agents, it will get smoother.

Report a Bad Reaction

Complain to the Food and Drug Administration (FDA) by calling 1-800-FDA-1088 or email:

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About the Author

Andrea Campbell is the author of 12 nonfiction books on a variety of topics. She is also an e-instructor, editor and columnist who has been writing professionally since 1991. Campbell, the daughter of a builder, writes frequently about home improvement. She uses her degree in criminal justice to write about forensic science and criminal law.