However LA can move Hg across the blood brain barrier. If you have more Hg in the blood than in the brain, it will tend to move Hg *into* the brain as seen in the Gregus study of mice. Andy Cutler, PhD Chemistry explains in this discussion. http://onibasu.com/archives/am/74605.html
Having most of the essential elements on a hair test show up low or low-norm is Cutler's "Rule 1." According to his theory, Hg fouls up movement--transport--of minerals in the body. This shows up as statistically strange results on the hair test.
Typically with Rule 1 tests, levels of toxins are rather low. AC does not trust the that the levels of toxins in hair will match body burden when a test matches a Rule. He tends to assume Hg is involved and proceeds to try HM detox.
A close friend had a Rule 1 test and very bad reaction to accidentally taking 100mg doses of ALA in a new formulation of her multivitamin for ten days in the months after Amalgam removal. Thankfully she is much improved to day after years of AC detox plus recommended supplements and some hormone balancing.
You may need some hormone balancing too since Hg really hammers hormone related systems.
In the Yahoo detox groups, the rule of thumb is that when a person has a bad reaction to taking a chelator or high thiol food or supplement, it is another indication that Hg is involved.
With the Rule 1 test, a bad reaction to taking high thiol foods and symptoms that match, I don't think you need the provoked urine test. Cutler and Pompa discuss how flawed they are.
My pre-chelation provoked urine and urine porphyrins tests were clearly normal ad the hair test was barely suspicious for lead and cadmium. However after 1 and 1.5 yrs of AC detox cadmium or lead were in the red and other toxins were in the yellow. The essential element section looked fairly normal. I've never had a hair test that was even close to matching a Cutler Rule I had a lead and cadmium problem, not a Hg problem. I chelated for over five years with DMSA plus ALA with life changing gains--normalized bone density and kidney numbers, improved mood, intellectual ability, and a LONG list of little things that greatly improved or went away.
So DMSA is quite effective for lead--when taken in a safe way!
Results of DMSA Treatment Study, James Adams,et al http://www.scribd.com/doc/15120628/Results-of-DMSA-Treatment-Study
Conclusions - benefits
•DMSA greatly increases excretion of lead, and some increase in excretion of tin, mercury,thallium.
•1 round of DMSA dramatically normalized glutathione levels for at least 1-2 months, and helped normalize platelet levels (marker of inflammation) for at least 4 months
•Severity of Autism Scale. Significant improvement in both groups
However if you take DMSA foolishly and when HMs are involved bad things can happen. Check out this by C Shade, a guy with a PhD in chemistry and whose speciality is enviornmental Hg. If a guy with that background can make this mistake, anyonoe can. As you correctly pointed out, there is so much confusion out there--maybe some of it from those who have something to loose if people understand the truth. https://www.youtube.com/watch?v=zc3eTtY39eU
When HMs are involved, there *will* be mood struggles. The brain, hormone systems and other related systems are so vulnerable. You don't need to be embarrassed. It is just chemistry. It gets better with safe forms of detox.