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A plant-derived, hair-coloring product sounded like a good idea until you started hearing scary stories about cancer and organ damage. Nature can be scary at times, but in the case of henna, it's not the natural product that's dangerous. The problem is the ingredients manufacturers use to alter the color or improve the convenience and performance of their products labeled as henna. Some of these additives are dangerous.
The Real Deal
Real, pure henna is a natural coloring derived from the plant lawsonia inermis. In its paste form -- the version you apply to hair -- it's brown, green or khaki and smells earthy, like soil or musk. Because most women don't want to smell like Jungle Jane, manufacturers sometimes add natural and harmless essential oils to mask the odor. Pure henna produces a brown, reddish brown or orange-brown color and is never "instant" in its effect. It continues to darken over several days following the application. The U.S. Food and Drug Administration (FDA) deems henna safe for use in hair coloring but not for use on eyelashes or eyebrows, or for skin applications such as temporary tattoos. Health Canada has approved natural henna for use in hair dyes and cosmetics.
Beware of so-called "black henna," "blue henna" or hennas that purport to produce a dark brown color. These products contain additives, which may be harmful. A primary culprit is the colorant p-phenylenediamine, or PPD, which comes from coal tar. Although the FDA allows the use of PPD in hair dyes, the agency cautions that PPD produces allergic reactions in some people. Health Canada allows the use of PPD only in hair products that you rinse off in less than 30 minutes to avoid prolonged skin contact. And just because a henna product is the right color doesn't mean it's all natural. Some brown henna dyes contain ingredients to make them darker, perform quicker or last longer. These may include solvents and other chemicals that have serious side effects.
If you apply a henna hair product that contains PPD, you may not immediately realize that you're about to embark on an odyssey of epic proportions. If you are allergic, your reaction can take two to 10 days to manifest and may include blistering, rashes and open sores. These reactions may leave permanent scars and also may cause you to develop new sensitivities to other products, including sunscreen, hair dyes and some clothing dyes.
Read the Label
The U.S. Packaging and Labeling Act requires manufacturers to list ingredients for all cosmetics sold in the United States. The Canadian government also requires ingredient labels on all cosmetics. So, read the label and see whether the henna product contains additives other than essential oils. Then, to put things in perspective, read the label on your favorite brand of mainstream hair dye. You'll find it contains some scary substances, most of which you can't pronounce. Even if you don't see PPD, look out for the following, which also are coal tar-based additives: 4-chloro-m-phenylenediamine 4-amino-2-nitrophenol 2,4-toluenediamine 4-methoxy-m-phenylenediamine 2-nitro-p-phenylenediamine 2,4-diaminoanisole Bottom line: Natural henna may be a good option for you if it's pure and if its limited color range works for you.