Many men choose to have facial hair for the aesthetic, but it turns out a mustache acts as a kind of shield. University of Kansas researchers looked at a bunch of men who were diagnosed with actinic keratosis on the head or face-- it is a scaly spot on the skin that can develop into squamous cell carcinoma, a type of skin cancer. They found that men who had a long history of sporting substantial "sheltering" mustaches (one that is at least a third of an inch thick) had a 16 times lower risk of developing actinic keratosis on their lower lip compared to their peers who never had a mustache. This held even when researchers took other risk factors into account. Study author Dr. Daniel Aires adds that growing a mustache now might not really help, as the men in the study had them for years and years, but it doesn't hurt to wear sunscreen or just grow the facial hair if you feel like it.