We all know how important it is to slather on sunscreen before heading outdoors, but did you know that it’s equally — if not more — crucial to apply SPF even when you’re inside? Or that you really should be reapplying about every two hours?
Because the hard and fast rules of UV protection are often blurred, we’ve reached out to dermatologists to find the truth behind sunscreen: when to wear it, how much to apply, and for how long.
Meet the experts:
- Elizabeth Tanzi, MD, is a board-certified dermatologist and associate clinical professor at George Washington University Hospital in Washington DC.
- Ava Shamban, MD, is a board-certified dermatologist in Los Angeles.
- Debra Jaliman, MD, is a board-certified dermatologist in New York City.
- David Colbert, MD, is a board-certified dermatologist in New York City.
- Joshua Zeichner, MD, is a board-certified dermatologist and the director of cosmetic and clinical research at Mount Sinai Hospital in New York City.
- Amy B. Wechsler, MD, is a board-certified dermatologist in New York City.
- Carmen Castilla, MD, is a board-certified dermatologist in New York City.
1. Sunscreen should be worn daily, no matter your location — indoors and outdoors.
“Completely indoor activities don’t require sunscreen, but many of us discount the sun that we get on a daily basis from just running errands and all the ‘incidental’ sun damage adds up,” explains Elizabeth Tanzi, MD, a board-certified dermatologist and associate clinical professor at George Washington University Medical Center. “That’s why we recommend daily sunscreen application, so you are always protected and don’t have to think about it.”
That means even if you spend most of your day indoors, says Ava Shamban, a board-certified dermatologist in Los Angeles, “UV exposure can occur from ultraviolet that penetrates through glass, which is UVA. UVA is emitted at the same level all day long whereas UVB, which is blocked by glass, peaks midday.”
2. For everyday wear, sunscreen should be applied to the face as well as other areas of concern.
Sunscreen should be worn all over the face, ears included, recommends New York City-based, board-certified dermatologist Debra Jaliman, MD. “Cover your entire face with sunscreen as well as your neck and hands,” she says. “You can apply it first thing in the morning.”
3. Follow the “two-finger” rule for your face and neck.
Board-certified dermatologist Carmen Castilla, MD, suggests following the “two-finger” rule for your face and neck. Dispense sunscreen along the length of your pointer and middle fingers. This amount will ensure that your face and neck are protected. “There really is no harm in applying extra sunscreen, so if you are unsure that you are adequately protected, just apply some more,” she says.
4. The magic SPF number is 30.
“The American Academy of Dermatology always recommends an SPF of 30 because it is clinically proven to be a sufficient amount of protection to reduce or minimize the adverse effects of sunlight,” says David Colbert, MD, a New York City board-certified dermatologist.