The drink is primarily composed of water and glucose-fructose syrup, providing readily available carbohydrates to support energy levels during exertion. Citric acid is included for its sharp, citrusy taste, while sodium citrate helps regulate acidity and maintain electrolyte balance. Natural flavourings and vegetable and plant concentrates (carrot and hibiscus) give the drink its distinctive mixed berry taste and colour. Essential electrolytes such as sodium and potassium are added to aid in proper hydration. Preservatives like dimethyl dicarbonate, potassium sorbate, and sodium benzoate help extend shelf life and ensure product safety. The beverage also contains sweeteners (aspartame and acesulfame K) and added B vitamins (niacin, pantothenic acid, vitamin B6, and vitamin B12) to support energy metabolism. ​

Boost Isotonic Sport Mixed Berry contains no major allergens such as milk, eggs, gluten, nuts, or soy. However, it does contain a source of phenylalanine due to the presence of aspartame, making it unsuitable for individuals with phenylketonuria (PKU). As with all food and drink products, it’s important to check the label for the most accurate and current allergen information, especially for individuals with allergies or dietary restrictions, as ingredients and manufacturing processes may vary over time. ​