Certain skin care and beauty myths have been circulating for decades. No one knows quite where these “facts” originated, and many are downright scary! Today, in honor of Friday the 13th, we’ll debunk a few of the most common beauty superstitions and misconceptions.

Myth: Crossing your legs causes varicose veins.

Crossing your legs will not cause varicose veins, and neither will wearing high heels or standing for long periods of time. Varicose veins are the result, however, of a preexisting condition of the veins called venous insufficiency, and crossing your legs may exacerbate this condition over time. Genetics play the biggest role in whether you are susceptible to vascular issues, so if you’re a habitual leg-crosser, you can rest easy knowing your go-to sitting position isn’t directly responsible for unsightly leg veins. Just keep in mind that it’s a good idea to get up and stretch your legs from time to time to regulate blood flow and promote healthy circulation, and even more so if a family member struggles with varicose veins.

Myth: Dabbing toothpaste on a pimple will make it disappear overnight.

You may remember dabbing a little toothpaste on blemishes as a teenager in the hopes that they would heal as you slept. The truth is that while toothpaste does indeed contain naturally drying ingredients like alcohol, menthol and hydrogen peroxide, placing products that are meant for the teeth on your face can cause redness, peeling and irritation. In other words, toothpaste will over-dry skin and disrupt its balance. You’re far better off with an acne treatment that contains gentle exfoliators and skin-healthy ingredients. We recommend LovelySkin Acne Care Gel, a formula that helps remove acne-causing bacteria with a blend of amino fruit acids.

Myth: If you pluck one gray hair, ten more will grow in its place.

This is thankfully false! Gray hair is caused by lack of melanin in the hair follicle. As we age, production of melanin, the pigment responsible for hair color, is slowed or stopped altogether, causing the shaft of the hair to appear gray or white. Each hair is on its own growth cycle and loses pigment in its own time. Plucking one hair will not have an impact on any of the hair follicles around it. That said, plucking gray hairs is never in your best interest, as this could permanently damage the follicle. To mask gray safely, you’ll want to consult with a colorist.

Myth: Pores have the ability to open and close.

It might be nice if we could will our pores to open and close depending on our needs. But pores are not muscles, and they do not have that ability. There is also no getting rid of them since they actually serve a crucial purpose in skin health. Pores house hair follicles, allow impurities to be pushed out and act as a gateway for balancing oils to reach the skin’s surface. Pores that are clogged with dirt, excess oil and other debris temporarily stretch and enlarge, becoming much more noticeable. Clear pores may be practically invisible at first glance, especially in those with fair skin, but they have not actually disappeared or shrunk. Adding a toner, such as Obagi Nu-Derm Toner, to your cleansing routine can help keep pores clear and free of debris.

Myth: Shaving hair will make it grow back darker and thicker.

Shaving hair will not change its color, thickness or rate of growth. Once hairs start to grow back post-shave, their blunt tips may feel stubbly or appear darker, but this is only an illusion. The hair shaft is naturally thicker at the root, and as hair grows, it will taper and appear as it originally did. This is true for all areas of the body. Dermaplaning, a professional exfoliation procedure that is used to remove dead skin cells and peach fuzz, will not cause fine facial hairs to grow back coarser.

Do you have a common beauty myth you’d like to see debunked? Let us know in the comments section.