I started with 100 mg oral DMSA but do not have any crash or something like that. I have a few amalgam fillings and my blood mercury level is normal. EDTA gave me kidney pain which indicates I was detoxing. I also took a dose of 50 mg R ALA that caused a severe crash together with other side effects . I even had a very strange feeling in one eye like when you feel something is stuck under your eye lid . Other forms of ALA never caused a problem.