Pre-workout supplements are among the most heavily-marketed products targeted to recreational and elite athletes. In this article we will discuss if they work and if they are safe. What are pre-workout supplements? Also known as multi-ingredient pre-workout supplements, these are products designed to be taken before exercise to enhance performance. They typically contain several ingredients in various quantities which are sometimes undisclosed and marked as “proprietary blends” (1, 2, 3). Common ingredients Common ingredients in pre-workout supplements include caffeine, creatine and beta-alanine (2, 3), branched-chain amino acids (BCAAs), nitrates (2), citrulline, taurine, tyrosine and B vitamins (3). Jagim et al. analysed 100 pre-workout products and found that, in average, they…