Parathyroid Hormone (PTH)

High parathyroid hormone (PTH) means the parathyroid glands are overactive. Causes include primary gland problems (adenoma or hyperplasia) or secondary causes like low calcium, vitamin D deficiency, or chronic kidney disease. Elevated PTH raises blood calcium, risking bone loss, kidney stones, weakness and fatigue. Evaluation involves calcium, vitamin D and kidney tests; treatment targets the cause and may include surgery.

Lowering PTH involves treating the cause: correct vitamin D deficiency and normalize calcium levels; for primary hyperparathyroidism, surgical removal of overactive gland(s) may be recommended. In secondary hyperparathyroidism (CKD), control phosphate intake, use phosphate binders, vitamin D analogues, or calcimimetics (e.g., cinacalcet). Hydration, avoiding high‑phosphate foods and reviewing medications that raise PTH are also advised. See your clinician for testing and tailored treatment.

Parathyroid hormone (PTH) is a peptide hormone produced by the parathyroid glands’ chief cells that maintains calcium and phosphate balance. It raises blood calcium by stimulating bone resorption, increasing renal calcium reabsorption, reducing renal phosphate reabsorption, and promoting conversion of vitamin D to its active form to enhance intestinal calcium absorption. PTH secretion is regulated mainly by circulating ionized calcium via negative feedback.

A PTH (parathyroid hormone) blood test measures the amount of parathyroid hormone circulating in your blood to evaluate parathyroid gland function and calcium balance. It helps diagnose conditions like hyperparathyroidism or hypoparathyroidism, investigate abnormal calcium levels, assess bone and kidney disease, and guide treatment. The test is a simple blood draw, usually ordered alongside serum calcium and sometimes vitamin D tests.

Most cancers do not raise true PTH; hypercalcemia of malignancy is usually due to PTH-related peptide (PTHrP). The principal cancer that causes markedly elevated PTH is parathyroid carcinoma. Rarely, ectopic PTH production has been reported from lung, renal, ovarian and certain neuroendocrine tumors. In most malignancy-associated hypercalcemia PTH is suppressed rather than elevated.

High PTH (hyperparathyroidism) does not typically cause direct weight gain. Elevated PTH and hypercalcemia more often cause fatigue, muscle weakness, bone pain, constipation and mood changes, and can be associated with weight loss. Indirectly, reduced activity or mood-related eating may lead to weight gain. If you have unexplained weight change with other symptoms, see a clinician for PTH and calcium testing.