Well I don't know about DMSA, but ALA appears to be safe, given that it is natural anti-oxidant. I wouldn't know if ALA caused me any damage, wouldn't be able to distinguish that damage from the bigtime mess the mercury/candida caused. I've only seen a site which claims that ALA backfired (3 x 100 mg per day) on some person who was formaldehyde (aldehyde) poisoned (after 3 days of usage). Those with diabetic neuropathy can take 600 mg ALA per day, so perhaps it is reasonably safe for most people.