Yes, I think it can be more stable to use DMSA along with ALA. It can help with side effects in some people and does increase the removal of mercury a bit more also.

But it is not crucial and some people do not tolerate DMSA, some cannot afford it, so they can just use ALA alone and do fine on it.

TGoss, a guy on here uses ALA alone as far as I know and is healing (well he was doing ok last I heard) on this. He was using about 40 mg or so, every 3 hours around the clock.