One smoothie and I am left clearing my throat for hours from a massive, almost instantaneous phlegm response to this product. I can't use this again, and made the mistake of getting two canisters - Amazon says it's not eligible for returns... What to do? There's an awful aftertaste that's from the stevia, I guess - I could put up with that to use this stuff up, but I can't hack this phlegm. I've never written a negative review before, but this is over-the-top not good.