In a small heatproof container, combine sugar and glucose syrup with 2 tablespoons (30 ml) of hot water and stir until fully dissolved. Add the citric acid and stir until dissolved. Allow the syrup to cool to room temperature.

Dissolve powdered actives

In a separate small bowl, dissolve the taurine and the measured vitamin mix in 1 tablespoon (15 ml) of warm water. Stir until fully dissolved. Separately weigh the caffeine powder carefully (50 mg) using an accurate scale and add it to the dissolved taurine/vitamin mixture, stirring thoroughly. Note: handle caffeine powder with caution — do not exceed recommended amounts.

Combine flavor and color

Add the natural/artificial flavoring and the single drop of blue food coloring to the cooled sugar-citric syrup and stir to combine.

Mix energizing components

Pour the flavor-sweetened syrup into a chilled tall glass. Add the dissolved taurine/vitamin/caffeine mixture and stir briskly to integrate.

Top with carbonated water

Carefully add the carbonated water (about 1 cup) to the glass, pouring slowly to retain as much fizz as possible. Stir gently once to incorporate — avoid vigorous stirring to keep carbonation.

Adjust sweetness and acidity

Taste and, if desired, adjust sweetness with up to 1 additional teaspoon sugar (dissolve first) or adjust acidity with a very small pinch more citric acid. If using sodium benzoate as preservative, add a pinch and stir to dissolve.

Serve

Add the ice to the glass if desired and serve immediately. Garnish with a lime wedge on the rim if using.