If you’ve ever taken a pre-workout supplement to get you energized for a tough gym sesh, then you may know the uncomfortable feeling that often comes with sipping these concoctions: your face gets itchy and your hands and feet feel tingly.
Pre-workout supplements, which can come in powdered or pill form, are supposed to help boost energy, strength, and endurance with a variety of vitamins and ingredients. They’re usually made with caffeine and B12 (for energy), creatine (to increase strength and muscle size), and the amino acid tyrosine (to improve performance and focus). But they also usually contain two ingredients that can give you that uncomfortable itching side effect: beta-alanine and niacin.
Beta-alanine is an amino acid that decreases muscle fatigue during high-intensity exercise by increasing carnosine in the muscle, explained Pamela S. Hinton, PhD, associate professor of nutrition and exercise physiology at the University of Missouri.
Overall, pre-workout supplements are generally harmless for the average healthy person when taken at the appropriate doses, says Patrick Saracino, CSCS, research assistant at the Institute of Sports Sciences and Medicine at Florida State University. Of course, you should always check with your doctor before starting a new supplement or workout regimen to be 100 percent sure. Regardless, the side effects of itching and tingling are nothing to be worried about — just make sure you read the package and don’t exceed the recommended serving size.