Everybody's body is unique, but there are some things that many people seem to believe about their bodies.

For example, some people mistakenly think that shaving hair can cause it to grow back thicker and darker. But Men's Health reported that this is not true. This is the reason why some men who want to grow beards prefer to shave. Robert Dorin, a hair restoration expert, said running a razor over one's hair near the root means that people can see a larger portion of the shaft's diameter when it grows back, but looks are deceiving.

Another lie about the body is that people lose heat through their heads. But Rachel Vreeman, M.D., assistant professor of pediatrics at the Indiana University School of Medicine, said heat escapes from every area of the body.

"If you're still cold, and you're not wearing a hat, by all means put on a hat," Vreeman said. "But there's nothing special about your head. There's no reason why a hat would keep you more warm than, say, putting on pants."

The third lie about the body Vreeman shared is that people only use 10 percent of their brain. "We love this idea that we have untapped potential and if we just like really were able to engage more of our brain, who knows what might be possible?" she said.

However, brain scans fail to reveal a huge and dark expanse of neurons that lie dormant in one's brain, since nearly all parts of the brain are working all the time.

Next, Vreeman debunked the notorious five-second rule. The five-second rule states that it's acceptable for people to eat food off the floor, just as long as it hasn't been on the ground for more than five seconds. But based on studies, Vreeman said the amount of bacteria that latches on the food depends not on how long it stayed on the ground but on the type of food and type of floor.

"Bacteria can live for weeks on the floor," said Vreeman. "And if you drop food on the floor, the bacteria transfer to that food almost instantly."

Lastly, some people think that urine is sterile. But researchers from Stritch School of Medicine, Loyola University Chicago, discovered that women's urine actually harbors at least 85 species of bacteria.

Study co-author Alan Wolfe, Ph.D. added that they haven't done the test on men's urine, but they don't expect the results to be any different. Despite being filled with bacteria, urine is not a complete waste. Wolfe said there's "urinary microbiota" that can help doctors treat infections and other issues.