I have to admit I don’t know much about the range of options for building bone. It could be that with osteopenia you might not need a bone builder. Part of that answer is probably what is causing the osteopenia. Going into menopause you’re likely to lose more bone because of lower estrogen, but you might be able to control that with diet/exercise. Some people have a family history of osteoporosis and it seems to be some other body process that is causing it - even with a good diet and exercise the bone just loses density.

If you need a bone builder, then you’ll want to take it, but with some of those drugs you HAVE to stay on medication because when you stop the bone loss starts up again at a rather fast pace.
My sisters were able to do 4-5 years on alendronate and then stop. They are 71 and 75 yo now. I waited to take anything and dropped into osteoporosis. Fosamax caused stomach problems so I did Reclast last year. The oncology rheumatologist says I should do Reclast again this year then maybe every other year. Within 6 months of taking Reclast my spine recovered 6% of bone. But that isn’t enough for some people.

You just have to make the best decision you can based on health history, diet/exercise history (bone density drop in spite of good food/exercise?), past chemical exposures (lead, cadmium, etc), expected future hormone levels (low estrogen), and the doctor’s explanation of what is currently recommended, and what she expects in the next 20 years for keeping your bones strong.