From sprouting a little scruff to going straight-up Zach Galifianakis, there's good reason to take a break from your razor this summer—and not just because it can speed up your morning routine. Research shows that growing a beard is actually the key to keeping you younger-looking, naturally moisturized, and cancer-free.

Here, five doctor-approved reasons to let your beard grow.

1. Sun Protection

According to recent research from the University of Southern Queensland, beards block up to 95 percent of the sun's UV rays, which can play a huge role in preventing basal-cell carcinomas (the most common form of all cancers). Key stats to know: Four out of five cases in men appear on the face, head, or neck and the sun is to blame for up to 90 percent of the visible signs of aging. So while facial hair won't keep your forehead from developing Jack Nicholsonesque creases, it will keep the bottom half of your face looking young.

2. Blemish-Free Skin

Forgoing the razor doesn't just hide blemishes—it actually prevents them. "Razor rash, acne, and folliculitis [hair-follicle inflammation] are often the result of shaving," said Dr. Shannon C. Trotter, a fellow of the Osteopathic College of Dermatology and a dermatologist at the Ohio State Wexner Medical Center. "Razors can irritate the skin or even spread bacteria, causing an infection of the hair follicle."

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3. More Masculinity

There's a reason you'd never steal a lumberjack's lady: The more facial hair a man has, the more masculine both men and women perceive him to be, according to research published in Evolution and Human Behavior. If pure, unadulterated masculinity is what you're going for, let your beard hang low. If you're looking to impress the opposite sex, skip the razor for 10 glorious days in a row; the study found that's the length women find the most attractive.

4. Natural Moisture

You probably didn't know your face has its own built-in moisturizing regimen—it's called your sebaceous glands (oil glands for short) and, according to Trotter, it secretes a natural oil that keeps skin moisturized. A thick beard not only prevents you from rubbing it off of your face, it also protects the face from wind exposure, which leads to redness and dryness (just in case you were planning your next high-altitude climb).

5. Trapped Allergens

Your nose hairs trap more than you think they do. In addition to what you see in a tissue, nose hairs trap pollutants that could actually cause your body harm. So the more hair you have under your airways (read: the bigger your beard), the more pollutants you're snaring every day, according to Dr. Clifford W. Bassett, Allergy and Asthma Care of NY medical director. Just be sure to treat your beard like any other filter and wash it regularly.