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1. You should brush your hair with 100 brush strokes every day.
Sorry, budding Rapunzels. The American Academy of Dermatology (AAD) addressed this conventional hair wisdom in a PSA. "Keep brushing to a minimum. Brushing your hair 100 strokes each day can cause split ends," the AAD wrote.
2. You should wash your hair every day.
"Washing your hair daily will remove hair's natural oils and proteins, drying it out," says stylist and Rahua brand creator Fabian Lliguin. "Then more products will be needed, causing a cycle of excessive product usage. Best to wash twice a week." (Or when your hair's dirty!)
3. Going outside with wet hair when it's cold can make you sick.
We've all heard this one from a concerned mom or grandmother, right? "Colds and other illnesses are caused by airborne pathogens like viruses and bacteria," James Choi, MD, says. "Standing outside with wet hair won't make you sick." Unless someone sneezes on you while you're standing out there, that is.
4. If you pluck a grey hair, two more will grow.
"Each hair follicle can reproduce [one hair] after being plucked, regardless of the color," Lliguin says. In fact, plucking is a bad idea. Think about what happens when you over-pluck your eyebrows. "Too much plucking will create a bald spot instead," Lliguin warns.
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5. You can "close your hair cuticles" with a cold water rinse and make hair shinier.
Ever been to a salon where they blast you with cold water at the shampoo bowl? It may feel refreshing, but it's not doing anything for your hair. "The degree to which cuticles are open or closed is not a function of temperature," cosmetic chemist Randy Schueller says. Water itself can cause hair follicles to lift away from the hair shaft (which leads to dull-looking hair) and things like relaxers and perms cause them to lift a lot. Physical and chemical damage can also cause follicles to lift. Conditioners can help with smoothing in this case, but cold water? Nope.
6. You can't dye your hair when you're pregnant.
This is one that often causes a lot of panic, but don't worry. You needn't give up your highlights once you get pregnant. Maternal-Fetal Medicine Specialist Cynthia Gyamfi-Bannerman, MD, at the New York Presbyterian Hospital tells us it's safe to dye your hair during pregnancy. "There are some caveats. Older dyes were formaldehyde-based. While it is difficult to find these, they should be avoided," she says. Gyamfi-Bannerman recommends that if you're doing DIY hair color, you should wear gloves and stay in a well-ventilated location.
7. A beer wash can make your hair stronger.
The common wisdom here is that the yeast and protein from malt and hops can help strengthen hair if you use it as a topical rinse. "Overall the alcohol will dry hair more than the proteins repairing it. Be cautious," warns stylist Lliguin. And who wants her hair smelling like beer?
Photo credit: Nacivet/Getty Images
This story originally appeared on ELLE.com
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