Looking for magnesium suppliment

I am desperately trying to find a magnesium supplement in Osaka. I have been looking everywhere. I use it for chronic constipation. Going even a day without has drastic consequences on my health. Does anyone here know where to find this supplement in Osaka?

try finding epsom salts rich in magnesium

So you haven't found it in drugstores?

If not, try www.iherb.com which ships from the US in less than a week normally. Shipping is around $4 and the vitamins themselves are usually cheaper than you would find them for in Japan.

I see.
In drug stores, they sell popular magnesium (マグネシウム) suppliments with calcium (カルシウム).
Like those.
http://www.dhc.co.jp/goods/goodsdetail.jsp?gCode=32322
http://www.otsuka.co.jp/nmd/product/item_202/
http://www.asahi-fh.com/products/supplement/dear-natura/basiccare08.ht...
http://www.fancl.co.jp/Items/Detail?category=02&item_code=5261a

If those suppliments are wrong,
you might want to try to show drug-store's staff a paper written in easy English.
"magnesium suppliment, no calcium" or something?

BTW, constipation is ベンピ(benpi) in Japanese.