The FDA approved only the purified form of stevia, called stevioside, as safe to use. If you see whole stevia leaves or crude stevia extracts at your local natural foods store, don’t buy them.
You may even get your sweet caffeine fix without calories or artificial sweeteners. Major U.S. soda companies now sell diet cola soft drinks sweetened with stevia. Some flavored waters also have stevia.
If you have diabetes, stevia could be a way to sweeten your yogurt or hot tea without adding carbohydrates.