Pure Liquid. Dietary Supplement. Non-Bitter. Zero Calories. NuNaturals uses our highly concentrated NuStevia extract and should not be confused with less potent powdered herbs or extracts. NuNaturals uses plant-based natural flavors that help to make our Stevia products the best-tasting ones available. NuStevia brand Stevia is a natural plant extract. NuStevia is a non-bitter extract with no unpleasant after taste.