Some energy drinks are sweetened with sugar (providing caloric energy), but there is also a variety of sugar free options available. Sugar-free energy drinks are commonly sweetened with non-nutritive intense sweeteners like aspartame.

Sugar-free energy drinks can contain one sweetener, or a combination of different sweeteners (e.g. aspartame, acesulfame K, sucralose). These sweeteners are among the most-tested and most-used sugar substitutes worldwide, and they all have an excellent safety profile. Numerous scientific studies demonstrate that these substances are safe for use as sweetening ingredients.

The safety of these sweeteners has been evaluated by regulatory institutions all over the world (e.g. the Food and Drug Administration in the US). Authorities rely on the safety evaluations of independent scientific advisory bodies such as the European Food Safety Authority (EFSA), the United States Food and Drug Administration (US FDA), and the Joint FAO/WHO Expert Committee on Food Additives (JECFA)