I would have started with a lower dose and not thought about any "high" or "target" dose, because you say you are mercury toxic (which causes all sorts of idiosyncratic problems) and therefore you just may not feel good with it at any dose. My wife and I (both of us are mercury toxic) started at 1.25mg. It gave her problems at that dose (she can't tolerate most supplements) and stopped taking it, and I eventually took 40mg but it took a few months. I stopped taking it because after stopping with the molybdenum, I couldn't feel any beneficial effect from it when I tried it a few more times. It also interacts with other minerals, and sometimes its hard to figure out whats going out of balance.