Stevia comes from a South American plant (Stevia rebaudiana) that happens to be very very sweet, but doesn't contain calories or nutritive value. It's like a natural form of the synthetic versions found in the wedding mint colored packets (powder blue, sunshine yellow, and It's-A-Girl pink) in any coffee shop you go into.
Because of this, Stevia also happens to be a huge business opportunity for food manufacturers.
I love it that there's a natural alternative to zero calorie synthetic sweeteners. And if you take a leaf from the plant, put it into your Darjeeling tea because you're worried about the whopping 16 calories found in a teaspoon of sugar, well that's fine.
What isn't nearly as great is that in order for manufacturers to make money on it, they have to take this leaf and put it into a packet, invent a new wedding mint color (light dusty green), and create a form of the natural plant that won't go bad, has the "right" mouth feel, and voila(!) a sweet profit margin.
Fair enough, they're a business. We should expect them to do this.
So it's really no surprise that the mass produced product would have other ingredients in it. What is amazing though is the other ingredients that are added -- and you absolutely won't believe this -- other sugars! These include erythritol (a sugar alcohol) along with dextrose (a sugar derived from starchy things like corn).
Stevia is already 200 times sweeter than sugar. Why on earth would you add sugar to a super sweet product that supposed to replace sugar? Truth really is stranger than fiction.
Regardless of the business reasoning, the outcome for us is that your consumption of this product acclimates your tastes to that super high level of sweetness. In other words, it creates, sustains, grows your sweet tooth, and that level becomes baseline for you.
The result is that you will crave sweeter things more often, and that Texas Honey Bun won't look so gross to you any more, and you'll start throwing gummy worms into your trail mix along with the caramels AND the peanut M&Ms.
So if you're sitting around the house, grumpy because you just don't crave sugar enough, now you know what to do: eat some form of a non-sugar sugar. Alternatively, you could totally go rouge and have a normal amount of normal sugar (darker is better) in your normal tea.