It's from the link posted by @tsc just above my post, to which I was replying.

I assume 680mg is not considered "low dose" since the report hypothesizes that it is helpful for bones.

I am skeptical of this report since there is no mention of the effect of strontium on DEXA scores.

I am not for or against strontium use at this point. I tried it 15 years ago, briefly, and might consider it after Tymlos and Reclast or even for maintenance after Tymlos, if studies show it is safe.

Strontium ranelate was taken off the market in Europe for safety concerns about clots and other cardiovascular effects but it seems it is now allowed for those without those risks. US manufacturers like Doctor's Best stopped making strontium citrate for awhile. I am not sure of the current status.

Strontium use is sometimes, perhaps, driven by fear of meds. I shared those fears, and also could not tolerate Fosamax or Forteo. But I am a big fan of Tymlos now (starting at a low dose) With fractures and severe DEXA score, I would not use a slower, gentler supplement like strontium but once stable I may look into it.