Your beard can protect you from the sun's UV rays.
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Your beard can protect you from the sun's UV rays.

Beard season is here, a.k.a. the NHL Playoffs, wherein players and fans traditionally grow their beards until their teams are eliminated. It's supposed to bring good luck, but superstition aside, there's a good reason for all players, and maybe even you, to keep beards on well past the playoffs, the Stanley Cup, and into those baseball diamond dog days of summer.

Beards can reduce anywhere from 50-95 percent of the ultraviolet (UV) rays reaching the skin underneath, according to a study conducted by researchers in Australia. "Facial hair has an Ultraviolet Protection Factor (UPF) of anywhere from 2 to 21," says Alfio Parisi, one of the study's authors and professor of radiation physics at University of Southern Queensland in Toowoomba.

UPF is the system of SPF (Sun Protection Factor) that's used for apparel, which, yes, UV rays can penetrate. A UPF rating of 15 is considered good, but the ratings go up to 50+, which is the most protective.

"The percentage of UV blocked to the skin depends on the thickness and angle of the sun," Parisi says. So how do you know if your beard is thick enough to obviate the need for some kind of sunscreen on your face? "Provided the beard is of reasonable thickness, I do not think there is a need to slather sunscreen over the beard due to the protection it provides," says Parisi. "However, it is necessary to use sunscreen over the parts of the face not covered by a beard."

Just what is "reasonable" thickness? "That can be difficult to quantify," Parisi says, "but it has to be a thick bushy beard and not just stubble." In the study, the shortest length that provided protection was at just .4 inches thick, with a UPF of about 2, while the strongest protection started with beards that were 3.5 inches thick, delivering a UPF of 21. Since it's unlikely that you're measuring your beard, and because those UPF numbers are also dependent upon the harder-to-quantify thickness of the hair on your face, we're gonna go ahead and say that if you can reasonably misplace, say, a tooth knocked out by a hockey puck in your beard, it has a good level of UPF. In less savage terms, if you have a beard like Henrik Zetterberg (especially the playoff-ready one from 2009), you're good to go without sunscreen. Ryan Callahan's stubble? Not so much.