Are Caffeine Based Preworkout and Energy Drinks Worth It? The Science, Dosing, and Side Effects

The Science

Caffeine, commonly found in coffee or tea, is a stimulant that affects the central nervous system and has shown to increase fat oxidation via mobilizing free fatty acids from intramuscular fat sores or adipose tissue (Haff, & Triplett, 2016, p.244). Due to it’s affect on the excitation-contraction coupling, caffeine enhances power production. Caffeine has also shown to improve the time to fatigue in both aerobic and anaerobic performance, decreasing the feeling of perceived exertion, improving mental alertness, and improving overall work capacity (Haff, & Triplett, 2016, p.244-245). Although studies have shown caffeine to improve peak power output, research is limited and can not establish power increase as a proven benefit (Haff, & Triplett, 2016, p.245).


Dosing recommendations for caffeine are 3 to 9 mg per kilogram of body weight for consumers, approximately an hour prior to exercise (Haff, & Triplett, 2016, p.245)

Side Effects

Aside from the addictive nature of caffeine, the supplement has the adverse side effects of gastrointestinal disturbances, anxiety, insomnia or restlessness, tremors, and even irregular heart rhythms. If discontinued, withdrawal symptoms may include fatigue, headaches, difficulty concentrating, and even flu-like symptoms (Haff, & Triplett, 2016, p.245). Consumers may rely on caffeine and develop dependence syndrome, feeling a sense of craving for the drug (Cappelletti, Piacentino, Sani, & Aromatario, 2015).


Cappelletti, S., Piacentino, D., Sani, G., & Aromatario, M. (2015). Caffeine: cognitive and physical performance enhancer or psychoactive drug?. Current neuropharmacology, 13(1), 71–88.

Haff, G., & Triplett, N. T. (2016). Essentials of strength training and conditioning. Champaign, IL: Human Kinetics.

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