I have been using a pre-workout for the past 3 years, but I'm not entirely sure why. I can drink my pre-workout 30-45 minutes before my workout starts and not feel a thing. No "tingling" that so many people talk about. No burst of energy and definitely no sustained energy. I've tried many different brands, even did the much talked about 2 scoops. Nothing. My current brand is PreKaged by Kaged Muscle, I like the flavor, but still not feeling a difference.
I do have a high tolerance to a lot of medications; Ambien did absolutely nothing. Hydrocodone just gives me cotton mouth and nothing for pain relief. I can even drink a cup of coffee or a pop and take a nap.