The adipocyte hormone that reports fat-store size and restrains appetite. Structurally it is Adipokine (167 aa, four-helix-bundle cytokine fold).

How strong is the evidence for Leptin?

PeptideHormone grades Leptin 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 Leptin?

The reported circulating half-life of Leptin is ~25–30 min.

Leptin

The adipocyte hormone that reports fat-store size and restrains appetite.

EndogenousEstablished

Fat tissue turns out to be an endocrine organ reporting on itself. That discovery ended the idea of adipose as inert storage.

Identity

Class: Adipokine (167 aa, four-helix-bundle cytokine fold)
Source: Adipocytes (white adipose tissue)
Receptor: Leptin receptor (LepR / ObR; JAK2-STAT3 signaling)

Key properties

Evidence floorClinicalREF1CLIN1

Molecular weight

≈ 16,026 Da

REF

Half-life (native)

~25–30 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

Leptin is secreted from fat in proportion to fat mass and acts on hypothalamic neurons to suppress appetite and permit energy expenditure — a signal of energy sufficiency. In common obesity the signal is high but the response is blunted (leptin resistance), so more leptin does not restore appetite control.

Reference notes

Leptin is a satiety signal of plenty, not of hunger — low leptin (starvation) drives the strongest behavioral response.
Leptin resistance, not deficiency, characterizes common obesity; rare congenital deficiency responds dramatically to replacement.
It links adipose tissue to the same hypothalamic circuits that the melanocortin and incretin systems act on.

Common questions

What is Leptin?: The adipocyte hormone that reports fat-store size and restrains appetite. Structurally it is Adipokine (167 aa, four-helix-bundle cytokine fold).
How does Leptin work?: Leptin is secreted from fat in proportion to fat mass and acts on hypothalamic neurons to suppress appetite and permit energy expenditure — a signal of energy sufficiency. In common obesity the signal is high but the response is blunted (leptin resistance), so more leptin does not restore appetite control.
How strong is the evidence for Leptin?: PeptideHormone grades Leptin 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 Leptin?: The reported circulating half-life of Leptin is ~25–30 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.Leptin and Obesity: Role and Clinical Implication · Frontiers in endocrinology, 2021 · PMID 34084149
2.Leptin Function and Regulation · Comprehensive Physiology, 2017 · PMID 29357132

External references

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