SPF Is Always Necessary, But Try To Avoid It Before Bed, Okay? Here's Why

If you want to find your way to the fountain of youth, make SPF your first port of call. Slathering up with a broad-spectrum sunscreen before walking out the door is the only way to protect your skin from the destructive glare of the sun, rain or shine. "Research suggests that daily use of sunscreen could decrease the incidence of melanoma, the deadliest form of skin cancer," dermatologist Dr. Henry W. Lim tells The American Academy of Dermatology. Wearing SPF products also prevents premature skin aging, such as fine lines, wrinkles, and hyperpigmentation.

When it comes to sunscreen, we're often told that there's no such thing as too much SPF. That's why many skincare enthusiasts entertain the idea of doubling down and wearing an SPF product to bed. Truth be told, when dermatologists advise you to wear sunscreen liberally, what they mean is quantity — not the extent of time. SPF ingredients might be a lifesaver for skin health, but they're not meant to be all over your face 24/7. An SPF-loaded beauty sleep can cause your skin more harm than good. Here's why you should not go to bed with a full face of SPF product.

At this point, you might argue that nobody in their sane mind would put on sunscreen at night when there's no sunlight. Well, your sunscreen is not the only thing that has SPF. Many moisturizers have SPF built into their formulations so people can get both sun protection and hydration in one swipe. If your moisturizer has SPF, save it for daytime use. 

Dermatologist Jody A. Levine tells NewBeauty, "One mistake I see people make is using their moisturizer with SPF when they go to sleep as a nighttime moisturizer. There is no need to use SPF at night, as it can unnecessarily dry out the skin or clog the pores." 

Besides, the sun protection ingredients used in sunscreens and sunblocks tend to be heavy and more suitable for daytime use, dermatologist Dr. Fredric Haberman points out. These ingredients may clog the pores of acne-prone skin. If you have a habit of sleeping on your stomach and pressing your face against your pillow, wearing an SPF moisturizer can predispose your face to a breakout. Furthermore, because the molecules of SPF ingredients are large, ramming them into your skin while sleeping can result in bigger pores.

If you've already bought an SPF moisturizer, keep it for daytime use. However, keep in mind that a moisturizer infused with SPF cannot replace sunscreen, the reason being you'll barely get enough sun coverage from sunscreen mixed with moisturizer. Even though it may state SPF 15 or 30 on the label, the amount you apply to your face won't be sufficient to provide that much coverage, and the moisturizer will dilute it, medical dermatologist Nava Greenfield points out (via Byrdie). As a result, your skin will only have an SPF of 10 to 12 in effect. 

Besides, it's not practical to reapply moisturizer all over your face every few hours as you do with sunscreen. That's why most dermatologists would recommend using a moisturizer and a sunscreen separately. The ideal approach is to apply moisturizer first, followed by a sunscreen of SPF 30 or higher at least 15 minutes before heading out. Sunscreen should always be the last step in your beauty routine to seal in the UV defense.  

Dermatologic surgeon Dr. Mary Stevenson echoes the sentiment. "My biggest issue with SPF moisturizers is that you're not putting enough on," Dr. Stevenson tells The Cut. "You want to put it on your face, jaw, neck, hands, anything that's exposed." If you'll be using SPF moisturizer, start at SPF 50 to make up for potentially inadequate coverage, advises dermatologist Dr. Ife Rodney. As long as it's daytime, more SPF is better than none.