Thanks, April - I will look for an Mg-only supplement. Any views on how much/best version? I did a bit of googling a few days ago on Mg and diarrhoea in case Mg was the culprit and found this by a Dr Carol Dean: Generally, magnesium will cause diarrhea because not enough is being absorbed into your bloodstream. If it doesnt make it into your bloodstream it ends up in your colon where it has a laxative effect. Here are four strategies to stop magnesium from causing diarrhea 1. Dont take all your magnesium at one time. Have two or three smaller doses throughout the day. 2. Try taking your magnesium with high fiber meals. We are meant to derive magnesium from food which slows down its absorption. 3. Dont take magnesium with meals. Yes, I know I just said take it with meals. That works for some and not for others. Fiber may bind up the magnesium too well preventing your gut from absorbing it. So try taking your magnesium on an empty stomach. 4. Try different types of magnesium. Youre probably using citrate. You can also try dimalate capsules which release slower. Magnesium oil is a great alternative as it bypasses your digestive system. And angstrom magnesium appears to absorb the best because its been broken down finer. I've been using citrate. I hadn't heard of Mg oil - I'm wondering if I should try it (if I can find it! Some of these things don't seem so easy to find in the UK). ETA: I've just ordered some Mg malate because I'm in a hurry to feel better! But I was surprised to find the dose seems huge compared to the 250 mg Mg in the Ca/Mg tablets - it's 1250 mg yielding 833 mg malic acid, 1-3 daily so presumably 417 mg/tablet. Any suggestions about dose & whether I should titrate up and what symptoms/reduction in symptoms I should look for gratefully received!