The drink comprises carbonated water, citric acid, taurine (0.4%), sodium citrate, flavourings, caffeine (0.03%), sweeteners (aspartame, acesulfame K), inositol, sodium benzoate, colours (sulphite ammonia caramel, riboflavin), and vitamins (niacin, pantothenic acid, vitamin B6, vitamin B12). It contains a source of phenylalanine due to the presence of aspartame.

Boost Energy Sugar Free Original does not list any major allergens such as milk, eggs, gluten, nuts, or soy in its ingredients. However, it contains aspartame, a source of phenylalanine, making it unsuitable for individuals with phenylketonuria (PKU). As formulations can change, it’s advisable to check the product label for the most current allergen information before consumption.