I use Jigsaw Slow Release Malate http://www.jigsawhealth.com/supplements/magnesium

I take 4 capsules - 2 in AM and 2 in PM - which is over 1k mg of magnesium. I had tried other formulas and types of magnesium, mostly citrate, and could never get up to this dose without a colon cleanse.

I've been on it for about 2 years and it's the ONLY supplement that I've taken which has provided a benefit. As an added bonus, it helps me sleep.