Yes, we have used both with some success. We are having separate issues now, but between ages 5-12 we did a lot of biomedical interventions, including gluten-free, casein-free diet, which we still do, seeing a DAN doctor once or twice, when we could afford it, and various supplements.
My son responds well to epsom salts (soaks) and Natural Calm magnesium.....gives him better focus very quickly and noticeably.
http://www.enzymestuff.com/epsomsalts.htm This explains it fairly well. We also removed a lot of phenol foods from his diet at one time when he was younger. Phenol made him hyper and spacey and killed what little attention span he has. I think it still does, but we aren't as strict now.
We briefly did b12 shots -- very good. Lots of results from that, but he was about 6 and we were working on basic communication skills, which we saw increase with the B12. Now we do oral methyl b12, never cyanocobalamin....just didn't work for us.
We are on a little break from most supplements, as puberty hit and we have other things going on. We regularly do b6, magnesium, cod liver oil, and some other b vitamins, but we find they don't work nearly as well when his diet is out of whack, as when he is eating well.
He tends to crave sugar, and have yeast-like gut problems. When his diet is clean, his supplements seem to work somewhat. We eat very little processed food.
There is a lot out there, bio-medically, and I believe a lot of it really works. But it is hard to stick to. Ask me questions and I can give you specific links.