I would try a different multi. Kirkman or klaire labs brands are great. There is also multi ANRC that was used in double blind study that showed efficacy in ASD which can be purchased.

http://autismnrc.org/assets/images/PDF%20Files/...

As for magnesium, we do Epsom salt bath (pharmaceutical grade) twice a week rather than supplementing. Some parents do daily as it has calming effect for some kids.

Good luck. We give our son a calcium/magnesium combined supplement from Kirkman.

Perhaps you need to give some calcium with it. May want to verify his calcium and magnesium levels.

The issue with OTC products is they often cause things to happen you do not expect. You have to remember that an ASD Childs brain chemistry is not the same as ours so they react differently to the most simple difference. Just as an example we can only give our children Delsum for cough, any of the other products cause agression issues.

Sometimes it is an ingredient like a dye or even a natural in gradient causing the problem, it is trial and error.

He drinks calcium enriched almond milk, but we will check his calcium levels.