What is Somatostatin (SST)?

The brake on the growth-hormone axis — and much else. Structurally it is Cyclic peptide (14 and 28 aa forms).

How strong is the evidence for SST?

PeptideHormone grades SST 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 SST?

The reported circulating half-life of SST is ~1–3 min (very short).

SomatostatinSST

The brake on the growth-hormone axis — and much else.

EndogenousEstablishedCompare lineage

The system's brake. A growth axis with no off-switch would not be a physiology; it would be a tumour.

Identity

Class: Cyclic peptide (14 and 28 aa forms)
Source: Hypothalamus, pancreatic delta cells, GI tract
Receptor: Somatostatin receptors SSTR1–SSTR5

Key properties

Evidence floorClinicalREF1CLIN1

Molecular weight

~1,637.9 Da

REF

Half-life (native)

~1–3 min (very short)

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

Somatostatin inhibits GH (and TSH) release from the pituitary and broadly suppresses endocrine and exocrine secretion across the GI tract and pancreas. It is the inhibitory counterweight that, opposing GHRH, sculpts GH pulses.

Reference notes

Any account of GH timing has to include somatostatin — it sets the troughs between pulses.
Its broad inhibitory reach extends well beyond GH, into gut and pancreatic secretion.
Stable somatostatin analogs are long-established tools in endocrinology.

Common questions

What is Somatostatin (SST)?: The brake on the growth-hormone axis — and much else. Structurally it is Cyclic peptide (14 and 28 aa forms).
How does SST work?: Somatostatin inhibits GH (and TSH) release from the pituitary and broadly suppresses endocrine and exocrine secretion across the GI tract and pancreas. It is the inhibitory counterweight that, opposing GHRH, sculpts GH pulses.
How strong is the evidence for SST?: PeptideHormone grades SST 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 SST?: The reported circulating half-life of SST is ~1–3 min (very short).

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.Structure and Function of Somatostatin and Its Receptors in Endocrinology · Endocrine reviews, 2025 · PMID 39116368
2.Somatostatin · The New England journal of medicine, 1983 · PMID 6139753

External references

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