The problem with hair products :
Some hair products aren't all they're cracked up to be. Consider the following:
1. Shampoos contain 70 to 80 percent water, plus detergent, perfume, and conditioning oils. Harsh ingredients include formaldehyde, propylene glycol, and quaternarium 15. "Oily," "dry," or "normal" classifications depend on how much detergent and conditioning oils a shampoo contains. A "gentle" shampoo may be a regular shampoo with extra water. Detergents may dry out the hair and skin and irritate the eyes. But the chance of getting cancer from a lifetime of shampoo use is extremely remote.
2. Dandruff shampoos may keep your scalp from peeling, but they can also contain such irritants as coal tar, selenium sulfide, resorcinol, and cresol; if you are sensitive to them, they may even make dandruff worse. If a shampoo causes itching or burning, switch to another. To prevent the scalp becoming resistant to a dandruff shampoo's active ingredient, users should alternate between sulfur-based products.
3. Hair sprays can irritate the eyes, skin, and respiratory tract and should be used in a well-ventilated area. Pumps are safer than aerosols because they emit larger droplets that are less easily absorbed into the lungs. Styling foams are safer, but they often contain alcohol, which may dry the hair.
4. Permanent-wave solutions often contain ammonium thioglycolate, which may cause rashes on the hands and scalp. Look for ammonia-free solutions instead. Obstetricians and gynecologists say it's safe to perm or colour hair while pregnant.
Do hair dyes cause cancer?
For years dark hair dyes have been suspected of causing cancer. But most experts say there is little to fear, even though some hair dyes contain such potential carcinogens as coal-tar derivatives and paraphenylenediamine (PPD) compounds. But one would have to use them constantly over 20 or more years to even slightly increase the risk of certain rare cancers. Progressive hair dyes for graying men are not carcinogenic, but some products do contain lead, so wash your hands after use. Some dyes may trigger allergic reactions. Before using one, dab a bit behind one ear and leave it on for 48 hours. If you do develop a reaction, consider henna or vegetable dyes.