When people have no heavy or toxic metal concentrations in their body, there are generally no negative symptoms experienced when taking about 200 mcg of selenium a day, however when selenium is very low when first supplemented, and larger amounts are taken, adverse effects are very commonly experienced the first few weeks due to the heavy or toxic metals being eliminated by the body. In that case, Dr. Ronald Roth urges his patients to slowly increase their selenium dose from as low as 25 mcg per day, up to eventually the full dose, which generally is around 100 mcg, or sometimes higher, depending on circumstances... Full Text