Magnesium - How much is too much?

[Guest guest]

I've had to up the dose of mag for my 50 lb son as his constipation is getting

worse. He was on 200mg/day now he's on 500mg/day but still having troubles. I've

just started epsom salt baths too. I'm thinking about trying a mag cream as

well.

Should I give him more? I don't want to overdose him but how do I know if he's

getting enough or too much?

Thanks!