I wouldn’t consider a prescription med with osteopenia. But there are many things you can do to prevent it from progressing to osteoporosis. Unfortunately, a recumbent bike is not a weight bearing exercise, and won’t do anything for your bones. You can build your bones with a jumping program, if you haven’t had a fracture, 10-20 small jumps a day, 30 seconds apart. Also, try some weight lifting, light weights and build up slowly and also dancing. If you’re able, Pickleball is great at building bone. Read about separating calcium supplements or foods from grain, nuts, iron rich foods and beans by 2 hrs. Good luck