Let's start with the myth that I was so enamored with back in high school. Women's Health pointed out that pumping your mascara wand lets air into the tube and dries your mascara out. Great way for peope to spend more money on product. To get more product, try swirling the wand instead.

If your pores are a problem, it's easy to imagine them opening and shutting like tiny, demanding monsters that want water or astringent or blackhead strips or what have you. But Elena Arboleda, head aesthetician at Mario Badescu, told Refinery29 definitively that pores do not open and close, no matter how fabulous your facial makes you feel.

Drinking water is important for tons of reasons, but thirsty skin isn't one of them, Dendy Engelman, a dermatologist and cosmetic surgeon in New York City, told Refinery29 that drinking water doesn't hydrate your dry complexion. In order to do that, you need a moisturizer. But you should keep drinking your H2O, because there are plenty of other benefits.

The myth that junk food causes acne may have been invented by parents who hoped to curb their teenager's appetite for Skittles, Snickers, and other classics. It's just a myth, though. Dermatologist David Bank told Real Simple that there is no connection between junk food and breakouts or acne.

Long believed to be a zit remedy, toothpaste isn't a useful tool for battling blemishes. In fact, Cosmopolitan warns that while the menthol may have a cooling effect, the other ingredients in toothpaste can be really aggravating to your skin.

Matt Fugate, a hairstylist at Sally Hershberger Downtown in New York City, tells Oprah.com that regular trims are good for your hair because they get rid of split ends and reduce breakage, resulting in healthier hair. But trims don't actually make your hair grow faster.

Sorry, Marcia Brady. According to Cosmopolitan, a few brushing before bedtime helps distribute natural oils which can temporarily make hair appear shiny.

There's a rumor that using the same shampoo prevents it from being affective. But celebrity hair expert Philip Kingsley told Marie Claire that there is no scientific evidence or reason to change shampoos if what you are using is working.

If you're looking for very long-term benefits, this one isn't a myth. "Wax rips the hair out at the follicles," Heather Woolery-Lloyd, a dermatologist in Miami explained to Real Simple. "And any repeated injury to the follicles over time―we're talking 20 years―could damage some follicles to the point that they don't grow back." So yes, in 20 years, you'll see less hair growth. If that doesn't do it for you, you can feel free to stick to shaving.

On the same subject, shaving your body hair doesn't make it grow back thicker. If it seems to, it's only because "hair just appears shorter and a bit more stubbly, making it seem thicker than it really is in between shaves," according to Women's Health.

Stained yellow nails — yuck. Fortunately, Bustle reports that a base coat keeps nails healthy.

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