I have been using Algae Cal/Strontium for almost two years with no side effects. My next scan is in a month. My pain has lessened and I am hoping for the best. I also do resistance training and strength training. Hopefully all will be well. There are many ways to increase your muscle strength without forward bends or stressing the spine. Even walking with a hip weight can strengthen the muscles.
I do have several friends that went from Osteoporosis to osteopenia or better using only AlgaeCal and Strontium, so I am hopeful and will keep you posted.