What are the major effects of calcitonin?

None!: Hi. Ha! That was easy! In humans, it's a superfluous hormone. In medullary thyroid cancer, it's useful as a tumor marker, and that's ALL it's good for. Losing all your calcitonin (as in thyroidectomy) has no physiologic effect. You lose it, you don't miss it. Calcitonin is FDA approved for osteoporosis, but it's worthless, and no one uses it.

Dr knecht: gave a good information on calcitonin. However Calcitonin has some utility in osteoporosis of the spine especially if phosphates like alendronate are contraindicated. it does help in reducing osteoporotic spinal pain. Though it use will soon become obsolete as more effective meds become widely available