I've been studying health and exercising with an Olympic trainer for years. First, nearly all vitamins sold at CVS, Walgreens, Costco, Walmart, etc. are cheaply manufactured. Don't even bother. These are also the vitamins pharmaceutical companies study when they wish to discredit the healthfulness of vitamins in general. Next, health requires diet, exercise, and supplementation for nutrients that can't easily be foun…
Most of them want to create the perception that you can "feel" the results of taking the supplement, so they contain stimulants like gotu kola, synephrine, etc. Some of these, like synephrine definitely are not safe (raise your blood pressure... small doses of that get me to 180/115) and other ones are questionable.