It's honestly the best thing ever. Evolution did well when it invented this stuff.
It's the most extreme painkiller capable of nullifying any physical pain, and the effects under an adrenaline rush are just awesome. It's like there's no more limit to physical capacity, and it's loving amazing in a fight or sparring session. It's like you think and then your body does and you don't feel anything and you don't feel strained.
The side effects thereafter are kind of stuff though. It's like the day after a hard workout, except compressed into 30 minutes of dead.