Interesting. I appreciate your suggestion, but I looked up the content of calcium in burdock and its (60mg per 122g), only 20mg more per carrots which I eat a lot more of and have no problem with. Beside I was taking a tincture, and not really taking enough to warrant excess.
Despite this, I may have made a mistake in my accusation of taking burdock. I had eaten a high fatty meal a day before I started taking the burdock tincture so it could be the result of the fatty food taking its toll to come out of my system. Never the less, it didn't appear to help much, for the next couple of days I did feel more fatigue. Only when I started chewing on ginger and drinking lemon did I feel my energy start returning.