Keep in mind that the International Society of Sports Nutrition indicates that if dosing caffeine based on body weight, the range for optimal effectiveness is 3-6 milligrams per kilogram or 1.3-2.7 milligrams per pound of body weight. For a 150-pound person, this would be a range of 204-408 milligrams of caffeine. That’s a big range! Know where your pre fits in it before you take it, and if you’ve only ever taken 100 milligrams of caffeine at a time, perhaps don’t jump right to 350 milligrams before an important workout.
That said, you can also take some control of the situation by paying more attention to your other pre-workout nutrition.
“If you ever drink coffee on an empty stomach, you know the feeling: light-headed, jittery, and sometimes even nauseous,” explains Krissy Kendall, Ph.D., in the article “3 Mistakes You’re Making with Your Pre-Workout.” “If you drink a pre-workout with 200-300 milligrams of caffeine without eating anything, you can feel exactly the same way.”
The answer, Kendall says, is to treat your pre-workout meal just as seriously as you treat your pre-workout supplementation. “Having a small meal 30-60 minutes before you take your pre-workout can help minimize side effects like these,” she says. “Plus, those extra nutrients will help you push through your workout.”