How Safe Are Energy Drinks?

Energy drinks—they are a purported panacea for late night studying, long work weeks, midday pick-me-ups, and more. While energy drinks have been around for more than 40 years, their popularity has skyrocketed over the past decade. According to Allied Market Research, the energy drinks market will reach $108.4 billion by 2031 and is currently expanding at a compound annual growth rate of 8.2%. But with such rapid growth, many people are wondering: Are energy drinks safe?

Although the specifics vary between brands, most energy drinks contain a few core ingredients: caffeine, taurine, B vitamins, and herbal extracts. Caffeine acts as a stimulant in the central nervous system, leading to increased levels of excitatory neurotransmitters (Somers et al. 2020). This can increase not only cognitive arousal and aerobic endurance, but also heart rate and blood pressure. Caffeine intake of up to 400 mg per day is generally considered safe, though this threshold applies only to adults with no underlying health conditions. Energy drinks contain an average of 159 mg of caffeine per serving (Jagim et al. 2023).

Taurine is an amino acid found in the brain and muscle tissue of humans and other mammals. It appears to play a role in mitochondrial function and aerobic metabolism, as well as in the contraction and relaxation of muscle fibers (Gutiérrez-Hellin and Varillas-Delgado 2021). Studies have also shown that taurine supplementation can decrease blood pressure and that it may act as an inhibitory neurotransmitter in the brain (Caine and Geracioti 2016). However, the exact mechanisms by which it is involved in these processes are poorly understood, as are its potential interactions with caffeine (Caine and Geracioti 2016).

B vitamins play an essential role in energy metabolism and red blood cell production, as well as many other processes, but current evidence does not support the claim that they improve cognitive or physical function in the absence of deficiency. Most Americans obtain adequate amounts from their diets (Kaur et al. 2022). That said, only a few of the B vitamins have established upper limits, and the amounts found in energy drinks are unlikely to cause toxicity (Jagim et al. 2023).

Lastly, most energy drinks contain one or more herbal extracts, such as ginseng, Ginkgo biloba, and guarana. While there are various claims tied to these herbal extracts, there is little evidence to support such claims. Moreover, the doses in energy drinks often are not quantified, complicating efforts to assess their effects (Jagim et al. 2023).

Perhaps it is unsurprising then that it is difficult to separate the effects of caffeine from the effects of other ingredients when evaluating energy drinks. Indeed, most of the improvements to physical and cognitive performance seen with consumption of energy drinks have also been seen with consumption of caffeine alone (Jagim et al. 2023). One study from 2017 investigated the effects of energy drinks versus caffeine alone on blood pressure and electrocardiograph (ECG) findings (Fletcher et al. 2017). Systolic blood pressure was significantly higher in the energy drink group 6 hours after ingestion, but this difference had dissipated by the 24-hour mark. The ECG revealed a slightly longer corrected QT interval at 2 hours in the energy drink group, but this change was gone after 4 hours, and this study had a small sample size, with only 18 people included (Fletcher et al. 2017).  (The QT interval is a measurement of the time it takes for the heart’s ventricles to contract and then relax.) There have been numerous case reports of adverse cardiovascular events, including myocardial infarction, arrhythmia, and cardiac arrest, following the consumption of energy drinks (Cao et al. 2021). But these reports can be misleading. Most of those who presented with such conditions did so after consuming multiple energy drinks or energy drinks mixed with another substance, namely alcohol or stimulant drugs (Cao et al. 2021).

For now, energy drinks appear to be safe, at least in the short term. Due to the lack of long-term studies, it is impossible to say whether energy drinks confer any lifetime cardiovascular or neurological risks for consumers, especially for those who habitually use energy drinks over periods of months to years. Current recommendations suggest that, among others, people with a history of cardiovascular disease, children, adolescents, and those sensitive to caffeine should avoid energy drinks, or consume them only after consulting with a health-care provider (Jagim et al. 2023). Otherwise, as in many things, moderation is key.ft

References cited are available at content.ift.org/dec-2023.