Research shows that caffeine intake shouldn’t exceed 6 milligrams per kg of body weight per day (this would be about 600 mg for a 200-lb man or 450 mg for a 150-lb woman).
Energy Surge contains 100 milligrams of caffeine per serving, which means that most people can safely “stack” it with any well-dosed pre-workout and still be within the maximum daily dosage guidelines.