Testosterone is the male sex hormone. It’s involved in a lot of things that are important for guys, including our sexual drive, our energy levels, our libido, our erectile function, even our overall mental wellbeing. We do know that after the age of 30, a guy’s testosterone levels typically decreases by 1 to 2% every year. And at the age of 45, about 40% of guys are experiencing low testosterone levels. Good thing is that we do know what low testosterone is and there’s ways in which we can accurately diagnose this as well as treat it.