Having a pre-workout or smashing a can of red bull before a workout may be your pre-training ritual, but is it actually hurting your results? The kick from these products can give you energy on days when you really aren't feeling it and they can make you feel like a superhero in the gym, however the negative impact they are having on your progress has to be addressed.
What these stimulants are doing is 'stealing' energy and creating a debt that must be paid. Everytime you take a stimulant you are stressing your adrenal glands, do this often enough and you will crash, no way around it. The overexertion of the adrenal glands also drives up cortisol, somthing we do not want. Coritsol is the stress hormone and is catabolic - it breaks down tissue, the more cortisol you have the more your gains will suffer. Cortisol is also made from the same mother hormone as testosterone - pregnenolone, the more pregnenolone is used to make cortisol, the less there is to make testosterone, again diminishing your progress.
Furthermore the false energy you get from these stimulants will mask the fatigue your body has from training, you can no longer tell if your body is actually feeling good or of it needs a break, you just power through regardless, in time this will lead to a crash or possibly even injury.
So stop having those stimulants! Wean yourself off them, drink water or normal coffee instead and learn to listen to your body! edit.