How much are you taking, and what is the chemical composition? The reason you want to supplement with both is that calcium salts and magnesium salts partially block the absorption of the other. Supplements are very much concentrated compared to dietary sources, so if you're only taking magnesium salts, you're probably not getting enough calcium in your diet. That could also cause twitching. Here are the Natural Pharmacy articles in www.iherb.com : http://healthlibrary.epnet.com/GetCo...chunkiid=21795 for magnesium and http://healthlibrary.epnet.com/GetCo...chunkiid=21612 for calcium.

You can get the combination in Oz. I just brought up Google Australia and typed in "Calcium magnesium complex" to get this: http://www.google.com.au/search?q=ca...U&start=0&sa=N . Here are a few of the sites:

http://naturalhealthdirect.com.au/pr...ba5a1e201a386d

http://www.melrosehealth.com.au/prod...&products_id=3

http://www.pharmacyonline.com.au/nat...in-p-2028.html

http://www.paylesschemists.com.au/pr...8&SubCatID=150 (they don't list ingredients, so you'd have to check it out first)

http://www.goldenglow.com.au/product.asp?pID=131&cID=3

If you haven't ordered from the internet yet, it can be intimidating. If that's the case, just do it. I've bought virtually all of my supplements, and most of my electronics, power tools, and non-food pet supplies on the internet for about 10 years now with almost no problems. The ONLY problem ever (including buying from eBay) is that an electronic piano keyboard was delivered damaged. They took it back at their expense, and sent me another one.