What can calcium supplements do to you if not needed?

Excess intake: Ingesting too much calcium may cause kidney stones, milk-alkali syndrome, or interference with iron absorption it can lead to hypercalcemia, with symptoms of increased thirst, urinary frequency, nocturia, anorexia, nausea, lightheadedness, and mental confusion.

Excess calcium.: If you get more than you need, and your parathyroids are normal, you will urinate or defecate the excess. No problem.