Understanding Parathyroid Hormone (PTH): Normal vs Optimal Ranges

?What is Parathyroid Hormone (PTH)?

Parathyroid hormone (PTH) is secreted by the parathyroid glands and is the main regulator of calcium and phosphorus balance. When blood calcium drops, PTH rises to increase calcium release from bone, reduce calcium loss in urine, and activate vitamin D (calcitriol) in the kidneys to improve intestinal calcium absorption. PTH should be interpreted together with calcium, vitamin D, phosphorus, and kidney function.

!Why It Matters

High PTH is seen in primary hyperparathyroidism (usually a benign adenoma) and in secondary hyperparathyroidism due to vitamin D deficiency or chronic kidney disease. Persistently elevated PTH accelerates bone loss and increases kidney stone risk (especially when calcium is high). Low PTH is uncommon but can occur after neck surgery and can cause symptomatic hypocalcaemia.

Reference Ranges

Lab normal ranges may vary between laboratories. Optimal and longevity targets are based on research literature and should be interpreted with your physician.

Symptoms of Imbalance

• High PTH (primary): kidney stones, bone pain, fatigue, constipation, depression
• High PTH (secondary): often asymptomatic; may show bone pain or muscle weakness
• Low PTH: tingling, muscle cramps, tetany

How to Improve Your Levels

• 1If vitamin D deficient: optimise 25-OH vitamin D and dietary calcium to reduce secondary PTH elevation
• 2Address kidney disease and phosphate burden if CKD is driving PTH
• 3Primary hyperparathyroidism: surgical evaluation when indicated
• 4Avoid excessive calcium supplementation without guidance (can worsen stones in some cases)

When to Test

Evaluation of abnormal calcium (high or low); osteoporosis assessment; kidney stones; suspected vitamin D deficiency with bone pain; chronic kidney disease monitoring.

Related Biomarkers