The European Food Safety Authority (EFSA) says the safe daily consumption of caffeine by adults is 400mg, and 151mg of caffeine in a 500ml can of Red Bull and two cans of Talon each with 160mg of caffeine amounts to 471mg, which is 17.8% more than the safety threshold. A 2023 New England Journal of Medicine study found that 68% of participants who consumed 1.5 cans of top 10 energy drinks daily for 30 days experienced a reduction in heart rate variability (HRV) (mean SDNN decreased from 42ms to 31ms) and 12% developed symptoms of caffeine dependence. According to the US FDA database, 89% of the cases of emergency heart palpitation caused by energy drinks in 2022 originated from the top 10 energy drinks brands.
According to the risk of sugar, a 600ml can of the leading top 10 energy drinks brand has 69g of sugar (17 teaspoons), which is more than 276% of the WHO recommended daily allowance of 25g. A Harvard School of Public Health study showed that adolescents who drank two cans of sweet energy drinks daily had a 42% faster BMI increase and a 2.3-fold increased risk of insulin resistance after two years. Since 2023, a 15% health tax has been charged by Australia on the top 10 energy drinks that contain more than 5g/100ml of sugar, and thus the introduction of a zero-sugar version of Devil’s Claw (stevia glycoside replacement) followed, but with its sucralose concentration remaining at 0.018g/100ml still sparking controversy over the impact on intestinal flora.
Regarding cardiovascular effects, a 2024 Journal of the American College of Cardiology study reported that in the population drinking more than two cans (500ml) of the top 10 energy drinks per day, the incidence of QT interval prolongation increased from 1.2% to 4.7%, and ventricular premature beats increased by 3.1-fold. Norwegian Food Safety Authority analysis showed that the level of taurine in the top-selling brand was 2000mg/can (the upper limit has been recommended at 3000mg/day by EFSA) and that it has a synergistic effect that can cause abnormal neuroexcitability. In a Brazilian case in 2023, a 19-year-old male who drank three cans of one of the top 10 energy drinks daily for six months developed cardiomyopathy with a left ventricular end-diastolic diameter (LVEDD) that rose from 49mm to 55mm.
Evidence on liver and kidney burden suggest that the top 10 energy drinks often contain levels of niacin (vitamin B3) between 200%-500% of the daily value. A subsequent Johns Hopkins University study found that long-term (>3 years) daily drinkers were 28% higher in mean ALT (liver enzyme) levels and also had a steeper rate of decline in glomerular filtration rate (eGFR) of 0.8ml/min/1.73m² per annum compared to controls. In 2022, Health Canada insisted on all of the top 10 energy drinks being labeled as having a “limit of 1 can per day” following tests that found that one of the brands had 35mg of niacin in one can (the UL is 35mg/day).
At the neuropsychiatric level, the caffeine half-life of the top 10 energy drinks was extended to 8.5 hours among teens (in contrast to 5 hours for adults), lowering sleep efficiency (SE) by 23%. According to data from the Ministry of Health, Labour and Welfare in Japan in 2023, the incidence of anxiety disorders caused by energy drinks among 15-19 year olds increased by 41% year-on-year, with 76% of them being the top 10 energy drinks brands. The UK Committee on the Safety of Medicines found that the Guarana extract, containing natural caffeine, of one of the top 10 energy drinks increased the actual total amount of caffeine by 22 per cent above the stated amount, which would risk dose-control failure.
In Mexico, the top 10 energy drinks will have to be labeled “Not for minors” (from 2024), after seeing daily consumption of 1.8 cans by consumers between the ages of 12-15 years. The United States, on the other hand, still has no national age limit, thus having under-18s contributing to 34% of total sales of the top 10 energy drinks. Singapore’s Health Sciences Authority reduced the highest concentration of caffeine per 16-ounce serving from 240mg to 160mg through mandatory reductions (<100mg/100ml), but the world’s top 10 best-selling energy drink product line has not adopted this regulation.
According to the Nielsen 2023 report, 62% of top 10 energy drink consumers incorrectly believe that “vitamin supplementation can counteract health risks”, when in fact one can of vitamin B6 brand contains 250% of the daily allowance, and long-term overconsumption causes peripheral neuropathy. In the area of industry self-regulation, the lead companies such as Red Bull launched 200ml low-volume multipacks (caffeine content reduced to 80mg) and labelled the EU market as the “dangerous mix with alcohol” but left the US version with the classical parameters and propaganda sales.
Clinical nutritionists recommend the use of EFSA guidelines to limit the number of consumption of the top 10 energy drinks to no more than 3 per week, and avoid consumption with alcohol or sports supplements. In 2024, Celsius was warned by the FDA for making the “Enhanced metabolism” claim, having to re-label its product and paying a settlement of $12 million. Industry figures report that since warning labels became tough, per capita consumption of the 10 most popular energy drinks on the Norwegian market dropped by 39%, which testifies to the effectiveness of the risk warning.