What are alternative ways to treat osteopenia (or osteoporosis) without using prescription drugs?

Osteoporosis. The best way to treat with over the counter medications is with vitamin d supplementation as well as with calcium. Typical diets do not contain enough of these. Also, your skin helps to convert vitamin d into the usable form for your body so be sure to get outside.
Be active. Start with low impact exervcises, such as tai chi or similar activities. Having a diet that is well balanced and includes enough calcium is quite important as well. Try to avoid diet things that cause you to leech out calcium from your bones, such as caffeine.
Many good approaches. As my colleagues have mentioned, weight-bearing exercise is helpful. Avoid excess animal protein, sodas & smoking & limit simple carbs, alcohol & caffeine- these increase acidity & cause bone loss! emphasize vegies & fruits. Vitamin d (5000 units a day), vitamin k, magnesium & boron are very helpful. See http://www.Huffingtonpost.Com/christiane-northrup/osteoporosis-treatment-a_b_585528.Html.
Bones are protein . Eat enough protein, do wieght bearing exercises. Optimize hormone levels keeping testosterone and Progesterone high enough and cortisol low enough through proper diet. Sunlight is extremely improtant.