OVERVIEW Parathyroid glands are four tiny glands found in our neck right next to our thyroid gland. As part of our endocrine system, these glands produce parathyroid hormone (PTH). Along with vitamin D and calcitonin (a hormone produced by the thyroid gland), PTH regulates the calcium and phosphorus homeostasis in the bloodstream, a crucial process in bone growth and bone cell activity. When these parathyroid glands are under-active, they have the challenge to produce enough