Know that spending money on pre-workout is an expensive way to just get in caffeine, which is the only proven supplement to boost workout performance.
Did you know that past a certain dosage caffeine is banned in the Olympics because of its performance enhancing effect!
Most pre-workout drinks just have a high caffeine content that is actually doing anything.
The other ingredients in pre-workouts have varied testing results to support any claims so it would be prudent to concentrate on proven supplements i.e. caffeine.
Not only is it less expensive it also will guard against you reacting to the other ingredients that form pre-workout powders, itching, redness etc.