ALA = inorganic mercury, DMSA/DMPS = methylmercury?

I think this study raises the possibility that ALA might be a more effective chelator of inorganic mercury. While DMSA/DMPS might be more effective chelator of methylmercury

Since mercury toxic people most likely have both forms of mercury in them, it may be wise to use ALA in combination with either DMSA and/or DMPS

it might also explain why some people like me seem to max out on a positive reaction to DMPS, but was still getting a positive result from ALA. It's very possible that with the DMPS I chelated all of the methylmercury that I could, leaving only inorganic mercury (which needed ALA as a chelator) as the problem