Parathyroid Hormone

Adequate magnesium intake keeps PTH in its optimal range and protects bone density and calcium homeostasis. The Coimbra Protocol targets PTH suppression to the lower end of the normal range as the primary indicator of adequate vitamin D activity. Vitamin D suppresses PTH; the more vitamin D is working at the cellular level, the lower the PTH. High PTH indicates that vitamin D is not being absorbed or utilized effectively. Parathyroid hormone controls calcium levels in the blood by signaling bone to release calcium when blood calcium is low. Measuring blood 25(OH)D levels to determine dosage is misleading for resistant patients because levels may appear adequate even while cellular response remains insufficient. When magnesium levels are low, PTH rises to retain more magnesium, mirroring its response to low calcium. In boron deficiency, PTH rises compensatorily in response to vitamin D resistance, attempting to maintain calcium balance. Boron deficiency causes PTH dysregulation, breaking down the mineral balance that keeps bones strong and joints healthy. Elevated PTH can signal either calcium deficiency or magnesium deficiency, creating a diagnostic overlap. Elevated PTH is itself…