Label-Declared Caffeine, Taurine, and Co-Ingredient Disclosure in 532 Energy Drinks: A Cross-Sectional Survey across Eleven Markets

Energy drinks are sold worldwide as a compositionally defined category, with no harmonized definition across jurisdictions. Typical concentrations have been reported market by market, but whether they are set product by product or held constant across a market, and whether the amounts determining co-ingredient exposure can be read from the label, remain unknown. This study examined label-declared caffeine and co-ingredient composition in a cross-sectional convenience sample of 532 commercially available ready-to-drink products from 43 brands across eleven markets with differing compositional and labeling regulations; products entered the sample where composition was published for the market concerned, so the findings describe the sampled products rather than national markets. One caffeine concentration recurred across the category, as did one taurine concentration among products stating an amount, held at the market level in several European markets, though not in the United States or Japan. The two varied independently, so the fixed ratio they appear to form is arithmetic rather than a formulation rule. Most co-ingredient declarations carried no amount, and the labeling regime, not the ingredient, decided whether one appeared, with quantification scarcest for constituents carrying published safety thresholds. Where a concentration is a market constant, intake is governed by the volume consumed rather than the product chosen, and across much of the category the amounts needed to apply an existing exposure assessment are absent from the label. Because these concentrations are declared rather than measured, chromatographic assay of these products would test their validity for exposure assessment and quantify the botanical caffeine the declared values omit.