Hi msfbradley, welcome to the board
. IN THE USA we can't get strontium renalate, but many of us take strontium citrate. I've been that that for almost 5 year and haven't had any negative side effects. Diarrhea, upset stomach, vomiting, mild headache and mild stomach pain are some of the possible side effects, but many of the people i know taking SC have not experienced any of these. You can do a search and find more info about SR.
For me me the only "side effect" has been improved bone density and and as a bonus nice strong fingernails. take care...phyllis