Skin-telligence: What You Need to Know—and Forget—about Your Epidermis

This article is not meant to diagnose or provide medical advice—that responsibility lies with physicians. The author is not a licensed medical professional.

Beauty may only be skin deep, but who doesn’t want to be beautiful?

No one, it would seem; the U.S. Census data and Simmons National Consumer Survey (NHCS) reported that 1.35 million Americans spend $500 or more on skin care products within a three-month timespan.

That might be because there’s a lot of ground to cover. According Forefront Dermatology, the organ amounts to 15 percent of your body weight. So remember that next time you’re on the scale.

If you’re looking to maintain, improve or simply learn more about the casing holding together your insides, read on for the truth about the body’s dynamic tissue.

You Only Need to Apply Sunscreen Once, and Only When Its Sunny: FICTION

Time to reapply. “You have to reapply sunscreen every two hours at the beach and every time after you go swimming,” says Debra Jaliman, M.D., world-renowned board-certified NYC dermatologist and author of the book, Skin Rules: Trade Secrets from a Top New York dermatologist. It’s especially important to apply sun protection when it’s not that sunny, adds Skin Authority CEO, founder and product formulator Celeste Hilling. “UV radiation from the sun comes right through clouds. UVA rays are very long and penetrate deep into the dermis layer of the skin, where new skin cells and collagen are formed.”

Exfoliate Daily: FICTION

Washing away dead and dry skin is healthy, but don’t go overboard. “Using an exfoliant every single day is too irritating for the skin,” says Dr. Jaliman. “Exfoliate twice a week. For those with sensitive skin, we recommend a mild exfoliant no more than twice a month.” Adds NYC-based dermatologist Marnie Nussbaum, M.D., “Frequent exfoliation can cause redness, irritation and micro tears in the skin, which can be sources of infection and blotchiness.”

Warm Water Is Best for Washing Your Face: FACT

While cold water might feel refreshing after a hot summer day, and hot water feels therapeutic in winter, resist both extremes. “When you’re using your cleanser, use warm water—not hot, not cold,” says NYC-based dermatologist Neal Schultz, M.D. “Hot water over-dries your skin, and cold water makes it difficult to get all of the dirt and debris off that the cleanser is capable of removing.”

Your Skin Will Be Fine If You Sleep with Makeup On: FICTION

No level of exhaustion or inebriation makes it OK to sleep in a made-up face. “If you leave your makeup on at night, you will end up with clogged pores and breakouts,” says Dr. Jaliman. Adds Dr. Zeichner, “Even if makeup is labeled as being able to last 24 hours, you should remove makeup every night. Sweat, oil and dirt accumulate on the skin during the day and can get trapped under makeup.” Makeup can cause irritation to the skin, leading to rashes, Dr. Zeichner warns, so the longer it’s on, the more likely it will leave an unwelcome mark.

Tanning Is the Best Way to Get Vitamin D: FICTION

Sorry to burst your bubble, but getting vitamin D is not a reasonable excuse for lying out as long as it takes to get that coveted tan. “One can get the recommended daily dose of vitamin D by eating a well-balanced diet including fortified milk, fatty fish and other foods,” says Dr. Nussbaum. “Your risk of melanoma, the deadly form of skin cancer, doubles after just five sunburns!” According to skincancer.org, one in five Americans will get skin cancer in their lifetimes. Vitamin D is available in supplement form, as well.

Inefficient Moisturizer Causes Wrinkles: FICTION

Worried about wrinkles? Step away from the sun and cigarettes, not the moisturizer. “Wrinkles are caused by smoking, sun damage, rapid weight loss, genetics and repetitive muscle movement,” says Dr. Jaliman. More so, wrinkles develop over time—not from using (or not using enough) lotion. “Wrinkles become present with age, however, overexposure to UV light can affect the connective tissue and elasticity, and eventually speed up the skin’s aging process.”

Food and Supplements Have an Affect on Skin Health: FACT

We’ve heard it time and time again: alcohol and sugar are terrible for the skin (in addition to waist lines). Instead, opt for more healthful and nutritious meals. “Many consider the Mediterranean diet to be the best type of food for skin health,” says Dr. Zeichner. “Rich in antioxidants and omega three fatty acids from fresh vegetables, it provides the necessary building blocks for healthy skin cell production.” Don’t like olives? “A supplement rich in vitamin C can also help produce healthy collagen, which strengthens the skin.”

Drinking Tons of Water Now Means Glowing Skin in the Future: FICTION

For the generations that appreciate immediate satisfaction, there’s a silver lining when it comes to H2O consumption. “The effects of skin hydration are pretty immediate,” says Arash Akhavan, M.D., board-certified dermatologist at Dermatology and Laser Group. “Skin dehydration can easily be reversed with just a day or two of adequate water intake.” So, how much water should we actually be drinking? The Food and Nutrition board recommends women ages 19 to 30 consume 2.7 liters daily and men ages 19 to 30 take in about 3.7 liters daily.

The Sun Eliminates Acne: FICTION

According to the American Academy of Dermatology, up to 50 million Americans are affected by acne. Not one of those 50 million should use sunning as a way to clear up pimples. “The sun actually stimulates sebaceous glands to produce more oil, which makes your complexion greasier and more acne prone,” says Dr. Nussbaum. “Furthermore, it increases the risk of acne scarring by producing post-inflammatory hyperpigmentation.”

Toothpaste Is a Great Pimple Remedy: FICTION

Save minty fresh toothpaste for cleaning your pearly whites. “Toothpaste may contain baking soda and other chemicals that can dry out occasional pimples, but it isn’t the right way to get rid of blemishes,” says Alina Cimpoeru, lead esthetician at The Guerlain Spa at The Plaza Hotel. In fact, the problem could get worse as the toothpaste dries out the skin, resulting in redness and peeling, she warns. Um … definitely not the result you were going for. Instead, Cimpoeru suggests applying a salicylic acid acne treatment on the blemishes. “It will reduce the inflammation and kill the bacteria that causes breakouts.”

Hilary Sheinbaum is a travel, health, food and lifestyle writer.