Science says it does not work. But those studies are always suspect because the controls are just not there. What I mean is the hebal stuff is gonna be more subtle and take longer to have effect than hard core drugs. If the test subjects were taking meds, smoking or drinking 6 cups of coffee a day that can counter the herbs effect. When I take Trib for a while I start to see zits so at my age that means it is doing sometime to boost testosterone.