What is Parathyroid hormone (PTH)?

The fast-acting hormone that raises blood calcium. Structurally it is Peptide hormone (84 aa).

How strong is the evidence for PTH?

PeptideHormone grades PTH at the "Established" evidence tier — its mechanism and core effects are settled across the peer-reviewed literature. It is catalogued as an endogenous signal the body produces itself, and the tier is an editorial judgment about the public literature that can change as the science does.

What is the half-life of PTH?

The reported circulating half-life of PTH is ~2–4 min.

Parathyroid hormonePTH

The fast-acting hormone that raises blood calcium.

EndogenousEstablished

Minute-to-minute custody of blood calcium, because the margin between a working nerve and a failing one is narrower than most physiology allows.

Identity

Class: Peptide hormone (84 aa)
Source: Parathyroid glands
Receptor: PTH1 receptor (PTH1R), a class B GPCR

Key properties

Evidence floorClinicalREF1CLIN1

Molecular weight

~9,425 Da

REF

Half-life (native)

~2–4 min

CLIN

Model dosing

Approximate values for the native hormone; engineered analogs are often deliberately larger and far longer-acting. Each figure carries its own provenance tier, and the floor is the weakest of them - the Standard.

Mechanism

Released within minutes of a fall in blood calcium, PTH acts on bone and kidney to raise it — mobilizing calcium from bone, increasing renal reabsorption, and stimulating activation of vitamin D. Its effect on bone is paradoxically dual: continuous exposure is catabolic, but intermittent exposure is anabolic.

Reference notes

PTH is the body's fastest defense against low blood calcium.
Intermittent PTH builds bone; continuous PTH breaks it down — a striking pulsatility effect.
It raises calcium partly by activating vitamin D in the kidney.

Common questions

What is Parathyroid hormone (PTH)?: The fast-acting hormone that raises blood calcium. Structurally it is Peptide hormone (84 aa).
How does PTH work?: Released within minutes of a fall in blood calcium, PTH acts on bone and kidney to raise it — mobilizing calcium from bone, increasing renal reabsorption, and stimulating activation of vitamin D. Its effect on bone is paradoxically dual: continuous exposure is catabolic, but intermittent exposure is anabolic.
How strong is the evidence for PTH?: PeptideHormone grades PTH at the "Established" evidence tier — its mechanism and core effects are settled across the peer-reviewed literature. It is catalogued as an endogenous signal the body produces itself, and the tier is an editorial judgment about the public literature that can change as the science does.
What is the half-life of PTH?: The reported circulating half-life of PTH is ~2–4 min.

Selected literature

Curated peer-reviewed reviews, sourced from PubMed. Selected for relevance, not exhaustive — open any entry on PubMed for the full record and its primary citations.

1.Parathyroid hormone and its related peptides in bone metabolism · Biochemical pharmacology, 2021 · PMID 34224692
2.Parathyroid hormone: past and present · The Journal of endocrinology, 2005 · PMID 16423810

External references

PTH in the public knowledge graph — the same entity resolved across the authoritative chemistry and protein databases.