Severe bone loss may not occur on aromatase inhibitors. It depends on starting point and rate of bone loss for an individual. I had a drop in bone density when I started, but the rate levelled off after the first year. I started off with osteoporosis and after five years had no fractures, even without bone meds.

The bone issues can be addressed with biphosphonates or Prolia during treatment with aromatase inhibitors, and have an added protective benefit for cancer. If a person cannot tolerate those, then Forteo, Tymlos and Evenity are options to grow bone back.

This decision will also depend on ER+ status, other pathology and Oncotype or Mammaprint scores. For many of us, the decision to take hormonal meds was easy and we dealt with bone issues if they arose, because cancer is life-threatening if it spreads.

Tamoxifen is another option for those concerned about bones, since it does not cause a decline in bone density and may even help with bones, since SERMS like Evista are used for osteoporosis. Here is one study:

"In the women given tamoxifen, the mean bone mineral density of the lumbar spine increased by 0.61 percent per year, whereas in those given placebo it decreased by 1.00 percent per year (P<0.001). Radial bone mineral density decreased to the same extent in both groups."

I did not experience any significant side effects from an aromatase inhibitor, nor did any of my friends. My only suggestion, validated by my oncologist, is to exercise more than 20 minutes: the pain goes away if you exercise longer.