Somehow, some fighters—including UFC fighter Lyoto Machida and Mexican boxer Juan Manuel Marquez—got the idea that they should give number 1 a second trip through their systems. Machida drank urine as part of his morning ritual, believing it is natural medicine that cleanses the body. Marquez used it before fights, because "that's where a lot of proteins and vitamins are."
Except, um, no. They're wrong on both counts. Your urine is about 95 percent water, with the rest consisting of toxins and other waste that your liver and kidneys separated from the nutrients your body actually needs. Therefore, drinking pee just puts back into your body things that it already determined to expel.
In the MLB, urinating on your own hands to toughen them up and combat blisters is not all that unusual. Current and former players like Rich Hill, Jameson Taillon, Moises Alou, Kerry Wood and Jorge Posada have all admitted to the practice. There's no science to back this up—if anything, urine should actually make your hands softer, if anything.