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Neuropeptide / peptide hormone

Spexin

Spexin (neuropeptide Q) is a 14-amino-acid endogenous peptide discovered by bioinformatic analysis in 2007. It signals through galanin receptors GALR2 and GALR3 and is studied for roles in satiety, glucose and lipid homeostasis, gut motility and cardiovascular function. This page is educational and not medical advice.

By The Peptides Codex Editorial TeamReviewed July 10, 2026
Length
14 aa
Class
Neuropeptide / peptide hormone
Function
Galanin-receptor (GALR2/GALR3) ligand; satiety and metabolic signaling
Context
Metabolic and neuroendocrine physiology research

A 14-residue peptide identified bioinformatically that acts through galanin receptors to influence appetite and metabolism.

Also known as: SPX · NPQ · neuropeptide Q

Part of the Metabolic & GLP-1 peptides cluster

Overview

Spexin (neuropeptide Q) is a 14-amino-acid endogenous peptide discovered by bioinformatic analysis in 2007. It signals through galanin receptors GALR2 and GALR3 and is studied for roles in satiety, glucose and lipid homeostasis, gut motility and cardiovascular function. This page is educational and not medical advice.

Source & context

Biological / chemical source: Encoded by the SPX gene (widely expressed tissues)

Primary research or clinical context: Metabolic and neuroendocrine physiology research

Sequence and receptors

The conserved mature peptide (NWTPQAMLYLKGAQ) is released from the SPX precursor between mono- and di-basic cleavage sites. Rather than binding a spexin-specific receptor, it acts as a ligand at the galanin receptors GALR2 and GALR3, placing it within the broader galanin peptide system.

Physiological interest

Spexin is expressed in liver, pancreas, visceral fat, intestine and adrenal gland. Research links it to food intake, body weight, lipid handling and stress responses, and reduced circulating levels have been reported in obesity, making it a candidate metabolic biomarker.

Sequence

One-letter sequence commonly cited for Spexin (educational; isoforms and modifications may differ):

NWTPQAMLYLKGAQ

NWTPQAMLYLKGAQ

N1W2T3P4Q5A6M7L8Y9L10K11G12A13Q14
Helical wheel projection

Residues plotted ~100° apart around an α-helix — clustering of one color reveals an amphipathic face.

Analyze sequences in the playground →

FAQ about Spexin

What is Spexin?+

Spexin (neuropeptide Q) is a 14-amino-acid endogenous peptide discovered by bioinformatic analysis in 2007. It signals through galanin receptors GALR2 and GALR3 and is studied for roles in satiety, glucose and lipid homeostasis, gut motility and cardiovascular function. This page is educational and not medical advice.

Is Spexin an approved medicine?+

Spexin is discussed here as a research / educational topic. Metabolic and neuroendocrine physiology research. This is not medical advice.

What is the typical length of Spexin?+

Spexin is commonly described as approximately 14 amino acids (Neuropeptide / peptide hormone).

Related peptides

Motilin
Gut hormone
Motilin is a 22-amino-acid gut hormone secreted by endocrine cells of the small intestine. It coordinates the migrating motor complex, the wave of contractions that clears the digestive tract between meals, earning it the nickname the housekeeper of the gut.
Obestatin
Gut hormone
Obestatin is a 23-amino-acid peptide cleaved from the same preproghrelin precursor that produces ghrelin. It was originally proposed to oppose ghrelin's appetite-stimulating effects, though its physiology and receptor remain actively debated in the research literature.
Albiglutide
Incretin mimetic (GLP-1 receptor agonist)
Albiglutide is a GLP-1 receptor agonist created by genetically fusing two modified GLP-1 sequences to human serum albumin, giving it a long half-life suited to once-weekly dosing. Approved as Tanzeum and Eperzan in 2014, it was later withdrawn from the market for commercial reasons and is now a historical case study.
Neurotensin
Neuropeptide
Neurotensin is a 13-amino-acid neuropeptide found in the brain and gut. Research examines its interactions with dopamine signaling and its roles as a neuromodulator and local hormone.

References & further reading

  1. 1.UniProtKB — SPX, Spexin (Human) Q9BT56
  2. 2.PMC — Emerging Roles of NPQ/Spexin in Physiology and Pathology
  3. 3.GeneCards — SPX gene (Spexin Hormone)
Disclaimer: Educational content only. Not medical advice. Not instructions for human use. Research peptides and unapproved products may be restricted or illegal to market for human consumption in your jurisdiction. Consult qualified professionals and applicable law.
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Cite this: Peptides Codex — Spexin educational profile.
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