Recent Dexa Scans Have Shown That I Now Have Osteoporosis

Recent dexa scans have shown that I now have osteoporosis with a high risk of fracture. I am a 66 year old female and have always had a healthy life style, including diet and exercise. I am small, white and weight 110 pounds, 5'2" height. My doctor has suggested alendronate sodium...but I do not like drugs and don't like the sound of the side effects. On Dr. Weil's site I saw an ad for AlgaeCal Plus. Would this supplement be an acceptable option?