What is Thyrotropin-releasing hormone (TRH)?

The hypothalamic trigger for the thyroid axis. Structurally it is Tripeptide (3 aa) — the smallest peptide hormone here.

How strong is the evidence for TRH?

PeptideHormone grades TRH 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 TRH?

The reported circulating half-life of TRH is ~2–5 min.

Thyrotropin-releasing hormoneTRH

The hypothalamic trigger for the thyroid axis.

EndogenousEstablished

A tripeptide at the top of the thyroid axis — the shortest sentence in the catalog, and among the most consequential.

Identity

Class: Tripeptide (3 aa) — the smallest peptide hormone here
Source: Hypothalamus
Receptor: TRH receptor (TRHR), a class A GPCR

Key properties

Evidence floorClinicalREF1CLIN1

Molecular weight

~362.4 Da

REF

Half-life (native)

~2–5 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

TRH stimulates the anterior pituitary to release TSH (and prolactin), setting the tone of the thyroid axis. At just three residues it is among the smallest peptide hormones, showing that potency does not require length.

Reference notes

TRH is only three amino acids — minimal size, full hormonal activity.
It drives both TSH and prolactin secretion.
It sits atop the hypothalamic–pituitary–thyroid axis.

Common questions

What is Thyrotropin-releasing hormone (TRH)?: The hypothalamic trigger for the thyroid axis. Structurally it is Tripeptide (3 aa) — the smallest peptide hormone here.
How does TRH work?: TRH stimulates the anterior pituitary to release TSH (and prolactin), setting the tone of the thyroid axis. At just three residues it is among the smallest peptide hormones, showing that potency does not require length.
How strong is the evidence for TRH?: PeptideHormone grades TRH 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 TRH?: The reported circulating half-life of TRH is ~2–5 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.Thyrotropin-releasing hormone analogs · Mini reviews in medicinal chemistry, 2006 · PMID 16472189
2.Thyrotropin-releasing hormone · The New England journal of medicine, 1982 · PMID 6798440

External references

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