The pre-workout supplement category has grown rapidly and these products now contain a growing list of nutrients. Although scientists often like to isolate variables in an experiment (e.g., a single nutrient) to examine its impact on the body, more studies are evaluating products with multiple ingredients.

One such study examined a low-calorie (15 kcal) pre-workout supplement consisting of common pre-workout ingredients such as creatine, beta-alanine, betaine, taurine, citrulline malate, beetroot extract, branched-chain amino acids, tyrosine, caffeine (300 mg) and more. The supplement was given to a group of healthy active men 30 minutes prior to a series of strength and power exercise tests. On a separate occasion, the men were given a placebo in a double-blind manner.

Compared to placebo, the men were able to perform more bench press repetitions to fatigue (9.8 vs 9.1) and achieve a greater total volume of work after consuming the preworkout supplement. Mean power during a 25-second sprint on a treadmill was 5% higher in the pre-workout supplement group compared to placebo. Other tests were not different between conditions. The level of perceived fatigue was lower and the level of alertness was higher in those who took the pre-workout supplement.

It’s impossible to attribute these positive effects to a specific nutrient combination given the nature of the experiment. The dose of caffeine likely had an important effect on the improvement in perceived effort and alertness. Some of the other ingredients like creatine and beta-alanine likely take several days or weeks to accumulate in muscles so any beneficial effects would likely accrue over a longer period of time. The findings provide support for use of multi-ingredient pre-workout formulas to improve subjective ratings of fatigue and alertness as well as improve certain aspects of strength and power.

Dr. Jeff Volek is a registered dietitian and Full Professor in the Department of Human Sciences at The Ohio State University. He has published 270 articles examining health and performance effects of low-carbohydrate diets and other dietary supplements including seminal work on creatine, carnitine and whey protein.

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