Myth 11: Brushing your hair 100 strokes a day will make it shine.
Marcia Brady, it turns out, was overzealous in her beauty routine. "One hundred strokes is too much," says Christopher Mackin, a trichologist (someone who studies hair) at the Gil Ferrer Salon, in New York City. "You'll do more damage than good." Hair will break if you tug on it too much. However, gentle brushing―a few strokes here and there―will make hair shine by distributing the natural oils from the scalp down the hair shafts and flattening the cuticles to make them reflect more light. More significant, light brushing removes impurities and stimulates blood flow to the scalp, which nourishes hair follicles and keeps them healthy.
Myth 12: Tanning or dotting on toothpaste can help get rid of pimples.
True to both, but don't run for the tanning booth or apply a Colgate face mask. "A particular wavelength of light has been shown to stimulate porphyrin, a chemical that eradicates the bacteria that cause acne," says Pinski. But while some sun exposure may help pimples get better temporarily, you can experience a rebound effect. "If the skin gets dry and damaged from the sun, your body's response is to produce oil," says Frank. Plus, sun exposure can lead to bigger problems, such as premature aging and skin cancer. As for toothpaste, it often contains menthol, which can help dry out a pimple. But other common toothpaste ingredients can irritate the skin. And there are much better over-the-counter options than toothpaste, such as Clinique Acne Solutions Emergency Gel Lotion ($17.50, sephora.com). If, however, you're on a reality-TV survival show and all you have is a tube of the white stuff, a couple of million viewers, and a blemish, a dab on your dot will work.