Look, we know that certain style and grooming choices—no matter how egregious we might find them—are ultimately a matter of opinion. However, some of them can get you into real, actual trouble.

No, really. It’s science. And research suggests that things like man buns and tighty whiteys can cause you to lose your hair, your friends and even your sperm. So as if the following trends weren’t bad enough on the surface level, here are scientific reasons you need to stop doing five things we’ve already asked you to stop doing.

Trust us, it’s for your own good.

Man Buns
Men’s Fitness asked 100 women how they feel about man buns. An overwhelming majority said they don’t seek out men with man buns and most avoid them. The men’s magazine also reported, however, that the man bun does more than scare off women; it actually rips out your hair. The phenomenon is known as traction alopecia, which can cause receding hairlines, permanent hair loss and acute baldness around your forehead and temples. Follicles under extreme tension are also prone to infection, so it’s no wonder women don’t want to run their fingers through those locked-up locks.

Shoes Without Socks
We already told you, “You look like a man-boy in a short suit. You look like a guy named ‘Blake’ who wants to tell you about his yacht that never leaves the slip.” And we told you that your feet probably smell. But we’re not the only ones behind this sentiment; science is, too. Sockless men are contributing to a plague of foot odor sweeping the nation—as ventilation decreases and bacteria and sweat increase—from more than 250,000 glands in each foot. According to The Guardian, socklessness has caused a dramatic rise in cases of foot odor and athlete’s foot. In fact, the sales of foot odor products have gone up more than 10 percent, and men have turned online to seek advice regarding odor-repellent products. Fellas, the answer is simple: Wear socks with your shoes!

Untucked Shirts
A recent Fruit of the Loom survey of 1,000 men between 25 and 60 years old found that 61 percent of those who tuck in their shirts were happy on the job (vs. 49 percent for non-tuckers). They were also 22 percent more optimistic about the future, had a 19 percent higher income and were eight percent more likely to date often—probably because they were 10 percent more likely to report being socially outgoing. More money, friends and dates could come to those who tuck.

Beard Transplants
Citing the “hipster beard craze,” recent reports indicate facial hair transplants, which can cost upwards of $7,000, have increased six-fold in the past five years. But hair transplant surgeons face challenges that all-too-often prevent optimal results, including hair survival (the transplanted hair can fall out after just two weeks) and concealing evidence of the surgical procedure (because the beard comes from hair on the back of your scalp). The past has seen a surge of concern surrounding scars that result from strip harvesting. These scars, caused by taking too much tissue or patient skin characteristics like poor scalp laxity, can be disfiguring and very apparent. Throw in the fact that a Tinder/Gillette study found that 100,000 college age guys got 19 percent more right swipes when they shaved, and it might be time to forget about that fake beard.

Tighty Whiteys
We don’t just joke that tighty whiteys aren’t manly; they’re actually killing your sperm and essentially your manhood. You see, wearing tight underwear increases levels of estrogen and lowers testosterone. When briefs constrict your package, blood vessels get compressed, causing ischemia or a lack of fresh blood and oxygen. The Leydig cells, which produce testosterone, suffer more than the Sertoli cells, which produce estrogen. Worse, high estrogen levels in men are associated with prostate cancer, enlargement of the prostate and breast growth—that is subsequently associated with increased risks of breast cancer. Switching to boxers or boxer briefs could naturally lower your estrogen levels by 20 to 70 percent. And, it almost goes without saying, increase your odds of hooking up astronomically.