Crossing Your Legs Doesn't Cause Varicose Veins (and 6 Other Beauty Myths Not to Believe)

Myth #1: Shaving will make hair grow back thicker.

There's no need to shy away from the blade: As opposed to what your mother may have told you, shaving will not make your hair grow back thicker, faster, or darker. The growth of hair is controlled by the follicle, and shaving doesn't affect the follicle or growth pattern whatsoever. Your hair just might appear more stubbly because the blade cuts the hair at the thickest part (the ends are blunt from the razor rather than naturally tapered).

What to Do About It
For starters, body hair is completely normal and shaving is a personal choice. However, if you do choose to shave, it can have its benefits. For example, dermaplaning (shaving your face with a single blade to help remove dead skin cells and peach fuzz) can create a more seamless base for makeup application, allow for better absorption of other skincare products, and act as a physical exfoliator for glowier skin. Just avoid making these shaving mistakes—steady downward strokes, with the blade at a 45-degree angle, should be employed to prevent nicks.

Myth #2: Smiling causes crow's feet.

This isn't completely true—it's actually more about squinting, says Doris Day, MD, clinical associate professor of dermatology at New York University Medical Center and author of Forget the Facelift ($12; amazon.com). Creases around the eyes are more prevalent in women with thin, fair skin. If your mother has crow's feet and you share her skin tone, you could be at increased risk of developing them, too. But the real culprits are usually sun exposure and repeated squinting, according to Dr. Day.

What to Do About It
Wear sunscreen and sunglasses every day to protect your skin from UV damage. "If you find yourself squinting often while you're inside, you might need glasses, or a different prescription, to reduce the strain on the skin around your eyes," says Whitney Bowe, MD, a dermatologist in New York City. "You should also use a moisturizing eye cream that contains antioxidants to keep the area hydrated and prevent damage from free radicals triggered by the environment."

A good eye cream for day: Caudalie VineActiv Energizing and Smoothing Eye Cream ($39; sephora.com). At night, apply an eye cream with retinol or peptides, which can strengthen and repair skin. Try Roc Retinol Correxion Eye Cream ($25; ulta.com). If you still develop these fine lines—and they bother you—talk to your dermatologist about whether Botox or Dysport injections could soften their appearance.

Myth #3: Hair loss is determined by your maternal grandfather.

Not so, says Joshua Zeichner, MD, director of cosmetic and clinical research in dermatology at Mount Sinai Hospital in New York City. It has more to do with your parents. However, if your mother's hair has thinned, it's not a foregone conclusion that yours will, too. "The risk is higher if you have a mother with female-pattern hair loss," says Jeffrey Epstein, MD, director of the Foundation for Hair Restoration in Miami and New York City. But many factors can affect your chances of hair loss—including the genes inherited from Dad, hormonal abnormalities, nutritional deficiencies, stress, and underlying health conditions, such as anemia and hypothyroidism.

What to Do About It
For healthy hair, eat a nutritious diet rich in iron, zinc, B vitamins, vitamin D, protein, and omega-3 fatty acids. It may help to take a nutritional supplement that's formulated to promote thicker, fuller hair, says Dr. Zeichner. (We like Nutrafol for Women, $79 a month; nutrafol.com.) You could also try an over-the-counter topical product containing minoxidil (an FDA-approved treatment for hair loss). But if you're noticing considerable thinning, see a dermatologist or cosmetic surgeon who specializes in hair loss and can provide a stronger treatment. One option is laser or light therapy, in which visible red light is absorbed by the hair follicle, potentially stimulating growth; another is platelet-rich plasma injections, in which your own plasma is injected into your scalp so growth factors in the blood encourage your hair to grow.

Myth #4: You can permanently shrink your pores.

Unfortunately, once pores have expanded (usually from persistent clogging and sun exposure), there's no way to make them disappear, says Day. (You can create some optical illusions, though.) "Pore size is determined by genetics. The more active the sebaceous glands, the larger your pores may appear," says Dr. Zeichner. Pores can become even bigger if you have acne, which may also run in the family, or don't take good care of your skin.

What to Do About It
Clear pores look smaller than clogged ones, so use products that contain salicylic acid or retinol to exfoliate the dead skin cells that line the pores. Try product with 2 percent salicylic acid, plus hydrating hyaluronic acid to prevent dryness. Also, wear sunscreen religiously. When the sun damages the collagen in your skin, your pore walls lose elasticity and sag, making pores appear larger. If you have oily skin, act fast when it comes to treating blemishes: The longer oil sits and clogs pores, the more they grow. Use blotting papers to remove oil throughout the day, says Dr. Zeichner, such as Too Cool for School Dinoplatz Blotting Paper ($8; toocoolforschool.com). And don't squeeze pores. Doing so leads to inflammation, which makes them bigger. If your pores are extremely noticeable and really annoy you, consider investing in microneedling. This treatment uses tiny needles to create microscopic wounds in the skin that trigger your body to build new collagen and elastin as part of the natural healing process. "This makes the walls of your pores firmer and appear smaller," says Dr. Bowe. "It also helps topical treatments work better."

Myth #5: Removing a skin tag—a small flap attached to the body by a narrow stalk—will cause more to grow.

That's false, according to Dr. Day; however the skin tag you removed may grow back, though. And if you are prone to skin tags, you will likely develop more, whether you remove one or not. Skin tags tend to run in families. They're incredibly common, says Dr. Bowe: "Almost everyone will develop a few throughout her life." Generally, they occur where skin rubs against itself or against clothing, which is why they often appear around the breasts, neck, and underarm area.

What to Do About It
See your dermatologist. Some people confuse skin tags with other growths, such as warts, which feel firmer than skin tags. If a skin tag isn't bothering you, there's no need to remove it. But if you want it removed, your doctor can snip it off, says Dr. Day. "Don't treat these yourself!" she urges. "The area can bleed a lot and get infected."

Myth #6: A lack of sleep causes dark under-eye circles.

Dr. Day says insufficient sleep doesn't actually cause permanent under-eye circles, but it does cause temporary changes that make the skin look darker. Natural shadows from deep-set eye sockets, blue veins that show beneath the skin, and darker pigmentation are all things you can inherit from either parent. But your habits matter, too: Sun damage, sleep deprivation, and aggressive eye rubbing can exacerbate under-eye circles, says Dr. Zeichner.

What to Do About It
Wear sunscreen daily and protect the area with sunglasses whenever you go outside. Eye creams with peptides or hyaluronic acid, like Neutrogena Hydro Boost Gel Eye Cream ($21; walgreens.com), can prevent or minimize under-eye circles. And creams with retinol, vitamin A, vitamin C, vitamin K, niacinamide, or growth factors can help strengthen and thicken the skin, making blood vessels less visible, says Day. Try Dr. Dennis Gross C + Collagen Brighten & Firm Eye Cream ($65; sephora.com). If you're prone to bluish discoloration, a product that has caffeine, such as 100% Pure Coffee Bean Caffeine Eye Cream ($29; 100percentpure.com), can constrict the blood vessels beneath the eyes, says Zeichner. The vitamin K cream Isdinceutics K-Ox Eyes ($93; isdin.com), has a similar effect, reducing reddish discoloration and puffiness. Have allergies? Take an antihistamine to reduce symptoms, and avoid rubbing your eyes. Be sure to remove eye makeup gently with a fragrance-free product, like Almay Oil-Free Eye Makeup Remover Liquid ($20; amazon.com). If all else fails, invest in a good concealer that's the right hue for you. We love Lancôme Teint Idole Ultra Wear Camouflage Concealer ($31; sephora.com), available in 19 shades.

Myth #7: You get varicose veins or spider veins by crossing your legs too much.

Crossing your legs won't cause either problem, says Paul Jarrod Frank, MD, a cosmetic dermatologist in New York City. "Bulging blue varicose veins have an enormous genetic component," he says. "They have to do with an inherited weakness in the valves of the blood vessels." The smaller, squiggly purple spider veins are less attributable to genetics; sun damage to fair skin is a bigger factor, says Dr. Zeichner.

Your best bets: If your mom has bulging veins, you can lessen your risk of having as many by keeping your weight in a healthy range, staying physically active, and never smoking. Avoid sitting or standing for long periods; this causes blood pooling and increased pressure on the veins. "Elevate your legs when you can, and flex and point your feet when you're sitting at your desk to stimulate circulation," says Dr. Day. To prevent spider veins, slather legs with a broad-spectrum sunscreen, like Coola Body SPF 30 Body Unscented Moisturizer ($32; amazon.com), every day they're exposed. If you're unhappy with spider veins or varicose veins, talk to a dermatologist or cosmetic surgeon about injections to minimize their appearance.