It’s up to 200 times sweeter Trusted Source than table sugar, but acesulfame potassium has a sour reputation.

Also known as acesulfame K or Ace-K, the ingredient is a calorie-free sweetener found in sugar-free products. Alone, it’s a white crystal powder with a slightly bitter after-taste. Because of this taste, it’s often blended with other sweeteners like sucralose (used in Splenda) or aspartame (used in Equal) — both controversial in their own right.

Ace-K can be found in soft drinks, protein shakes, drink mixes, frozen desserts, baked goods, candy, gum, and tabletop sweeteners. The Food and Drug Administration (FDA) approved of Ace-K’s use in soft drinks in 1998, increasing consumer exposure to the ingredient.

Though it’s considered safe by the FDA, some are convinced it has potentially dangerous health effects.