Most people get the best results by taking 100 to 300 mg of caffeine in the two hours before working out. The highest amount that most people can tolerate before hard exercise is 350 mg.
Is caffeine bad for you before a workout?
Overall, the research team found that taking a dose of caffeine 30 minutes before an aerobic workout increased fat oxidation during exercise regardless of the time of day. Caffeine also increased exercise intensity by 11% in the morning and 13% in the afternoon.
Is 100mg of caffeine good for pre workout?
However, most governments do offer rough guidelines when it comes to Caffeine consumption. If you're going to choose a pre workout containing Caffeine, then it's important to check the dose in each serving. As a general guideline, you'd expect to find around 100mg of Caffeine in a regular cup of coffee.