The data that support the findings of this study are available from the corresponding author upon reasonable request.
This study was approved by the Institutional Review Board (IRB) at University of the Pacific (Stockton, CA). All participants were provided written informed consent consistent with university requirements for clinical studies involving human subjects. The clinical study was registered onClinicalTrials.gov (NCT03196908).
This was a randomized, double‐masked (participants and care providers), placebo‐controlled, crossover clinical trial conducted at a university campus setting (July 2017 to December 2017). Healthy volunteers between the ages of 18 and 40 years who were willing to avoid ingestion of caffeine and energy drinks for 48 hours before each study day were eligible for enrollment. Participants were excluded if they had any known medical condition (confirmed through participant interview), were pregnant or breastfeeding, were current smokers, had a baseline QTc >450 ms, or brachial blood pressure >140/90 mm Hg. Those who were taking any chronic prescription or over‐the‐counter medications were excluded except those who had been taking oral contraceptives for over 1 month. An overnight fast (with allowance for water only) was required preceding every study day, and no food was allowed during the study monitoring period. A commercially available non‐caffeinated granola bar (Nature Valley Crunchy Oats ‘N Honey, General Mills) was provided after the 180‐minute time point upon participant request.
Participants were randomized into 1 of 3 intervention phases using a computer‐generated code fromhttp://www.randomization.com . Participants received two 16‐oz bottles of a commercially available caffeinated energy drink brand (drink A), another brand of a caffeinated energy drink (drink B), or a placebo‐drink (placebo) on 3 separate days with a minimum 6‐day washout period in‐between. The beverages were consumed within a 60‐minute period but no faster than 1 bottle in 30 minutes. Based on the package labeling, both drink A and drink B contained caffeine (304–320 mg/32‐fl oz), taurine, glucuronolactone, and vitamins along with other proprietary ingredients.24 Some differences between the 2 energy drink brands include the presence of carnitine, guarana, and panax ginseng. The placebo drink contained carbonated water, lime juice, and cherry flavoring. All drinks were packaged in identical, masked containers prepared within 24 hours of administration and stored in a refrigerator before administration.
This study was approved by the Institutional Review Board (IRB) at University of the Pacific (Stockton, CA). All participants were provided written informed consent consistent with university requirements for clinical studies involving human subjects. The clinical study was registered on
This was a randomized, double‐masked (participants and care providers), placebo‐controlled, crossover clinical trial conducted at a university campus setting (July 2017 to December 2017). Healthy volunteers between the ages of 18 and 40 years who were willing to avoid ingestion of caffeine and energy drinks for 48 hours before each study day were eligible for enrollment. Participants were excluded if they had any known medical condition (confirmed through participant interview), were pregnant or breastfeeding, were current smokers, had a baseline QTc >450 ms, or brachial blood pressure >140/90 mm Hg. Those who were taking any chronic prescription or over‐the‐counter medications were excluded except those who had been taking oral contraceptives for over 1 month. An overnight fast (with allowance for water only) was required preceding every study day, and no food was allowed during the study monitoring period. A commercially available non‐caffeinated granola bar (Nature Valley Crunchy Oats ‘N Honey, General Mills) was provided after the 180‐minute time point upon participant request.
Participants were randomized into 1 of 3 intervention phases using a computer‐generated code from
