Yes, unless they're caked in snow and ice. For centuries, bearded men have contended that a furry face is nature's insulation. In a 1854 philosophical treatise on the topic, a Mr. Thomas S. Gowing contended that a beard's function is to protect "some of the most susceptible portions of our frame from cold."
Science has since proved him right. A 2012 study in China compared the skin of nearly 100 men's upper lips to their upper (and hairless) cheeks. Lips were, on average, 1 degree warmer than cheeks, suggesting a clean-shaven man is more likely to lose body heat from a susceptible bare ledge.
That mystery solved, some scientists now contend that beards might actually be too good at their intended jobs. Physiologist Michel Cabanac says there's a real danger (however slim) a beard will overheat the brain. To compensate, he theorizes, evolution came up with an adaptation: hereditary male-pattern baldness.
Cabanac believes that less hair atop the cranium offers ventilation, which makes up for the heat-trapping chin pelt. He calls this hypothesis "thermoregulatory compensation." To test it he studied 39 men over 10 years. He found that, sure enough, men with higher beard lines — shaved or not — had the most receding hairlines.
There's one other downside to a fuzz face: ice. Polar adventurer Eric Larsen, who treks through minus-50-degree weather, finds he needs a well-shorn chin. "I try to shave as much as possible," he says. "The benefits of having a beard are outweighed by the energy it takes to melt the ice that forms on it."
Source: Popular Science