Hi, I been using preworkout supplements for about 1 year now. Not every day but most days, if I'm honest. They contain 5g creatine, 300mg caffeine, and a few other ingredients. One i was taking had dmaa in it too. I also take a fair bit of protein powder. I don't drink and my diet is pretty good. I'm 43 just! And exercise everyday and not overweight. My sister in law died last november of liver disease and it's really put the frighteners on me!