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 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 contain 18.4 ingredients with approximately 8 of them included in the “proprietary blend” with undisclosed quantities (3).
According to manufacturers, pre-workout supplements can improve exercise performance in the short term and facilitate training adaptations in the long term (2, 3).
Efficacy of ingredients
Caffeine has been shown to improve cognition and performance in endurance, power and resistance exercise when consumed in doses 3-6 milligrams (mg) per kg of bodyweight (2). For a 70 kg athlete, this means between 210 and 420 mg in a serving of pre-workout supplement.
Taurine present in pre-workout supplements in doses of 1.5 grams per serve can improve muscular endurance (2).
Ingredients like L-arginine and L-citrulline may increase nitric oxide, which increases blood flow to muscles, potentially enhancing performance. The effective dose for L-citrulline seems to be 6-8 g per day (2).
Creatine in doses of at least 3 g per day taken for at least 28 days can improve exercise performance by increasing phosphocreatine levels in muscle (2). Phosphocreatine provides energy during the first seconds of muscular activity.
Betaine can improve exercise performance via a few mechanisms in doses of 1.25-2.5 g per day, which are higher than those contained in most pre-workout supplements (2).
Beta-alanine in doses of 4-6 g per day for at least 14 days can improve high-intensity exercise performance.
Pre-workout supplementation doesn’t seem to increase strength but the caffeine in some products may mitigate fatigue over multiple reps when taken acutely or for less than 10 days. However, long-term supplementation may improve force production, especially in the upper-body (2).
In addition, acute intake of pre-workout supplements may improve muscular endurance. However, this effect is not clear when supplementing in the short or long term (2).
Some studies have reported improvement in upper-body and lower-body power production, including sprints and anaerobic cycling. However, these results are not consistent, especially with chronic use of pre-workout supplements (2).
Subjective benefits of pre-workout supplements include improved focus, fatigue, alertness and energy levels (2).
Other benefits of pre-workout supplements may include improved reaction time and increased energy expenditure when taken acutely, and improved body composition in the long term (2).
Two important concerns about pre-workout supplements are the possibility of harmful interactions between ingredients (1) and the contamination with banned substances (1, 2), heavy metals or stimulants (2).
Assuming the product has not been contaminated, most studies have found minimal side effects when pre-workout supplements are taken in recommended doses (2).
Pre-workout supplements in Australia
Some of the products available in Australia that have been batch tested for banned substances include:
- Musashi Pre-workout
- BodyScience KOS Pre-Workout
- True Protein Pre (with and without caffeine)
- Bulk Nutrients Pre Workout 101
The table below shows the ingredients present in the mentioned supplements. This is just to highlight the heterogeneity in the composition of different supplements.
The chart below shows a visual comparison in the amount of certain ingredients contained in the mentioned products (hover over for more details).
Summary and recommendations
Pre-workout supplements vary greatly in their formulations and therefore is very difficult to assess whether they are effective or not. Moreover, there is risk of contamination with banned substances.
If you want to experiment with a pre-workout supplement, keep in mind the following:
- Use a batch-tested product from a reputable brand, especially if you participate in competitions or get tested for substances at work
- Single components that have strong evidence that can improve exercise performance under specific circumstances are: caffeine, beta-alanine, bicarbonate, beetroot juice/nitrate, creatine and glycerol (1). Pre-workout supplements that contain those components in adequate quantities are more likely to be effective.
- As always, consult with a sports dietitian before making any changes to your diet or supplementation protocol
- Australian Institute of Sport. The AIS Sports Supplement Framework 2019. Australian Capital Territory: Australian Institute of Sport; 2019.
- Harty PS, Zabriskie HA, Erickson JL, Molling PE, Kerksick CM, Jagim AR. Multi-ingredient pre-workout supplements, safety implications, and performance outcomes: a brief review. J Int Soc Sports Nutr. 2018;15(1):41.
- Jagim AR, Harty PS, Camic CL. Common Ingredient Profiles of Multi-Ingredient Pre-Workout Supplements. Nutrients. 2019;11(2).