Secretoneurin (SN)
An endogenous peptide from secretogranin II — a chemoattractant and angiogenic signal, and an emerging heart-failure biomarker. A research peptide, not a drug
Secretoneurin (SN) is an endogenous ~33-amino-acid neuropeptide, one of the biologically active fragments cut from a large precursor protein called secretogranin II. That precursor belongs to the granin family — the same family that gives rise to chromogranin-A peptides such as catestatin and pancreastatin — and the secretoneurin segment is strikingly conserved across vertebrates, from sharks to humans, which usually marks a peptide as functionally important. It is stored in the secretory granules of neuroendocrine cells and neurons throughout the body and is released into the blood. Secretoneurin acts as a chemoattractant that pulls immune and vascular cells toward sites of inflammation, promotes the growth of new blood vessels (angiogenesis), modulates neurotransmitter release and neuroinflammation, and stimulates the pituitary release of luteinizing hormone. In people its most developed use is as a biomarker: blood secretoneurin rises in heart failure and other cardiac stress and carries prognostic information. SN is studied as a research tool and biomarker; it is not an approved medicine and has not been given to people as a treatment.
No established human dose Details ↓
Recommended Dosing
No established human dose
Secretoneurin is an endogenous human peptide that has never been given to people as a treatment. The human evidence is its blood levels (a cardiovascular biomarker) and its presence in tissue; the functional studies are in animals and cells, at experimental amounts that do not carry over to people.
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What is it?
The granins are a family of acidic proteins packaged in the secretory granules of neuroendocrine cells and nerves; the three main members are chromogranin A, chromogranin B and secretogranin II. Each is cut by processing enzymes into smaller peptides with their own activities — chromogranin A yields catestatin, pancreastatin and the vasostatins, while secretogranin II yields secretoneurin. Secretoneurin is a roughly 33-amino-acid peptide, and the fact that its core sequence is conserved all the way from fish to mammals is a strong hint that it does something biologically important.
Secretoneurin is found wherever neuroendocrine granules are — brain, pituitary, gut, pancreas, adrenal and thyroid — and in most tissues the precursor is almost fully processed to the free peptide, which also circulates in blood. One of its clearest actions is as a chemoattractant: it draws monocytes, eosinophils, fibroblasts, smooth-muscle cells and endothelial cells toward it, which is why it is studied in neurogenic inflammation and in wound healing, where it can promote the growth of new blood vessels (angiogenesis).
In the brain, secretoneurin is transported along sensory nerves and behaves like an excitatory transmitter, and its levels change in disease models — for example it is up-regulated in the striatum in a rat model of Parkinson's disease and L-DOPA treatment, suggesting a role in the brain's output pathways. It also has endocrine actions: the clearest is stimulation of luteinizing-hormone release from pituitary gonadotroph cells, pointing to a role in reproduction, and it increases feeding when injected into the brain of fish.
In human medicine, secretoneurin has advanced furthest as a biomarker. Its concentration in blood rises in heart failure and other cardiac stress, and it adds prognostic information in cardiovascular disease and in critically ill patients. A study of women with Takotsubo (stress) cardiomyopathy found a trans-cardiac gradient — higher secretoneurin leaving the heart than entering it — direct evidence that the stressed human heart produces and releases the peptide. Its receptor is thought to be a G-protein-coupled receptor but has not yet been pinned down.
Secretoneurin is an endogenous human peptide, a research tool and a biomarker, not a medicine. No published study has given secretoneurin to people as a treatment — the human evidence is blood levels and tissue, and the functional work is in animals and cells — it is approved nowhere, and material sold online as 'secretoneurin' is an unregulated research chemical. Nothing here is a dose or a therapy; this page records what the published science says about the peptide.
Mechanism of Action
Secretoneurin is a secretogranin-II-derived peptide that acts, probably through an unidentified G-protein-coupled receptor, as a chemoattractant and angiogenic signal, a neuroinflammatory and neurotransmitter modulator, and a stimulator of pituitary luteinizing hormone — and it is released by the stressed heart.
Chemotaxis and angiogenesis
Secretoneurin draws monocytes, eosinophils, fibroblasts, smooth-muscle and endothelial cells toward it and promotes new-vessel growth, through G-protein-linked, protein-kinase-C-dependent signalling (PMID 11245085) — a role in neurogenic inflammation and wound healing.
Neurotransmission and endocrine release
It acts as an excitatory sensory transmitter, changes in disease models such as Parkinson's (PMID 11672603), and stimulates pituitary luteinizing-hormone release in reproduction (PMID 19106223).
Cardiac release and biomarker
The stressed human heart produces and releases secretoneurin (shown by a trans-cardiac gradient in Takotsubo cardiomyopathy), and blood levels carry prognostic information in heart failure and critical illness (PMID 38663366).
Published Research
These are studies of secretoneurin read from their PubMed abstracts on November 6, 2026. They include two reviews of secretoneurin as a secretogranin-II-derived hormone, a human study of its trans-cardiac gradient in Takotsubo cardiomyopathy, an animal/cell study of its stimulation of luteinizing hormone, an animal study of its change in a Parkinson's model, and a review of its role in neurogenic inflammation and cell chemotaxis. Secretoneurin has not been given to people as a treatment in any published study; the human evidence is blood levels and tissue.
Secretoneurin as a secretogranin-2 hormone
A review of secretoneurin as the conserved central peptide of secretogranin II, with a diverse array of functions across nervous, endocrine and immune systems. It stimulates luteinizing-hormone synthesis and release, regulates reproduction (shown by gene-knockout and rescue experiments in zebrafish), stimulates food intake, has neuroprotective and neuroplastic (trophic) properties, and is chemoattractant in neuroinflammation — most likely acting through a G-protein-coupled receptor that has yet to be identified.
Is secretoneurin a new hormone?
A review arguing that secretoneurin, derived from the evolutionarily ancient secretogranin II, is an 'old peptide with emerging implications as a new multifunctional hormone'. It regulates neuroinflammation and neurotransmitter release, has therapeutic potential for inducing angiogenesis, stimulates pituitary luteinizing-hormone release (a role in reproduction), and increases feeding and locomotion when injected into the brain — likely via a G-protein-coupled receptor.
Trans-cardiac secretoneurin gradient in Takotsubo
In 15 women with Takotsubo (stress) cardiomyopathy, plasma secretoneurin was measured simultaneously in the aortic root and coronary sinus. The concentration was higher leaving the heart (coronary sinus) than entering it — a positive trans-cardiac gradient — supporting the idea that the stressed human heart produces and releases secretoneurin; blood levels correlated with NT-proBNP and kidney function. An observational human biomarker study, not a treatment.
Secretoneurin stimulates luteinizing hormone
The free secretoneurin peptide was isolated from goldfish brain and detected in the pituitary, with immunoreactivity in prolactin and preoptic cells. In dispersed pituitary cells, secretoneurin antiserum lowered LH while 1 and 10 nM secretoneurin raised LH release about 2-2.5-fold — similar to GnRH — and elevated calcium in gonadotrophs. The work supports secretoneurin acting as a neuroendocrine/paracrine stimulator of LH (a preclinical result).
Secretoneurin up-regulated in a Parkinson's model
In rats, destroying the nigro-striatal dopamine pathway (a Parkinson's-disease model) raised secretogranin II messenger RNA in the striatum, and chronic L-DOPA treatment raised it further; immunohistochemistry confirmed higher secretogranin II peptide in striatal neurons. The resulting rise in secretoneurin may help regulate the brain's output pathways after dopamine loss (a preclinical result).
Secretoneurin and neurogenic inflammation
A review of secretoneurin as a sensory neuropeptide in neurogenic inflammation. Synthesized in spinal ganglia and stored in the terminals of primary sensory neurons, it behaves as an excitatory transmitter and specifically drives the chemotactic migration of monocytes, eosinophils, fibroblasts, smooth-muscle cells and endothelial cells. Its receptors are G-protein-linked and its effects are blocked by inhibiting protein kinase C.
No Established Human Dose
Secretoneurin is an endogenous human peptide that has never been given to people as a treatment. The human evidence is its blood levels (a cardiovascular biomarker) and its presence in tissue; the functional studies are in animals and cells, at experimental amounts that do not carry over to people. No regulator has approved any dose, and no published human dose exists, so no amount is printed here.
What this rests on: PMID 38663366, PMID 19106223, PMID 22036841.
Educational information, not medical advice. The doses on this page come from approved labels, published studies and, where no study exists, amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
What a Buyer Needs to Know
What is sold, how it is mixed, stored and taken, and what is known about its safety, quality and legal status. Each part names its source. Where we have none, it says unknown.
What is sold
Unknown: we hold no label and no published test that says what forms or vial sizes Secretoneurin (SN) is sold in. A vial's own label is a seller's claim, not a source.
Mixing a vial: a worked example
Unknown: no human dose of Secretoneurin (SN) has been established (see No Established Human Dose below), so there is no amount to work out. The reconstitution calculator does the arithmetic for any vial, water and dose.
Storage before and after mixing
Unknown: no label or published stability study on file says how to store Secretoneurin (SN), before or after mixing. The mixing guide sets out the general rules, with their sources: keep a mixed vial in the fridge, and use it promptly, as the bacteriostatic water label says of any drug dissolved in it. The 28 days often quoted is the limit for an opened multiple-dose vial from a manufacturer, an outer limit set for sterility, not a time a mixed solution has been shown to keep. Nobody has published how long Secretoneurin (SN) stays intact once mixed.
How it is taken
Unknown: with no established human dose, there is no established way of taking Secretoneurin (SN). What the human studies gave and how is set out under No Established Human Dose.
What to expect, and when
How long it stays in the body: a half-life of not established for humans as a drug; an endogenous circulating peptide. After about five half-lives almost none is left.
When effects appear: unknown; no source on this page gives a time to effect for Secretoneurin (SN). Results reported in the studies are under Published Research.
Source: half-life: PMID 38663366.
Side effects, and when to stop or get help
From the Side Effects section: No human adverse-event data exist: no published study has administered secretoneurin to people; High blood secretoneurin is a marker of cardiac stress and worse prognosis in heart failure and critical illness (PMID 38663366) — an association and warning sign, not an effect of taking it; In animals/cells it is chemoattractant, angiogenic and stimulates luteinizing hormone (PMIDs 11245085, 19106223), so inflammatory, vascular and endocrine effects would be expected if administered; Material sold online as 'secretoneurin' is an unregulated research chemical of unverified content. Full list and cautions ↓
When to stop or get help: unknown; no label or trial on file sets rules for stopping Secretoneurin (SN). Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“Secretoneurin is an endogenous peptide that has not been given to people as a drug, so there is no human safety profile; the points below reflect that research and biomarker status”).
Interactions
Unknown: a PubMed search for human interaction studies of Secretoneurin (SN) (reviewed 2026-11-06) found none. Unknown is not the same as safe to combine.
Every peptide's record, with its source: the interaction matrix.
Checking what you bought
Unknown: no published independent test of Secretoneurin (SN) products is in our lab-results database yet, so how products sold under this name measure up is not known.
To read a certificate of analysis, paste it into the COA decoder. Trust & Verification explains what independent testing can and cannot show.
Legal status
US: Research Chemical (Not a drug: Drugs@FDA and the openFDA label endpoint hold no record, and FDA GSRS and ChEMBL hold no substance record for secretoneurin (searched November 6, 2026)). Sport: Not on the 2026 List.
Country by country ↓ · Regulatory tracker
Source: this entry's approval status and the WADA Prohibited List, as in Legal Status below.
Side Effects & Contraindications
Reported Side Effects
Secretoneurin is an endogenous peptide that has not been given to people as a drug, so there is no human safety profile; the points below reflect that research and biomarker status.
Contraindications & Cautions
Secretoneurin has no approved use and no label. These points reflect its endogenous, research status.
Legal Status
Secretoneurin is an endogenous human peptide studied as a research compound and cardiovascular biomarker; it is not a drug and is not approved in any country.
Frequently Asked Questions
?What is secretoneurin?
An endogenous human peptide of about 33 amino acids, cut from the precursor secretogranin II — a member of the granin family that also gives rise to the chromogranin-A peptides catestatin and pancreastatin. Its core sequence is conserved from fish to humans.
?What does it do?
It is a chemoattractant that draws immune and vascular cells and promotes new-vessel growth (PMID 11245085), modulates neurotransmission and neuroinflammation, stimulates pituitary luteinizing-hormone release (PMID 19106223), and is released by the stressed heart (PMID 38663366).
?Is it used in medicine?
Not as a treatment. Its developed use in people is as a biomarker — blood secretoneurin rises with cardiac stress and gives prognostic information in heart failure and critical illness. No human trial has administered secretoneurin, and it is approved nowhere.
?Is it available to buy?
As a medicine, no — secretoneurin has no FDA application or label and is approved nowhere. Material sold online as secretoneurin is an unregulated research chemical. Grey Peptides lists no sellers and recommends no source; this page records the published science.
References
- [review] Mitchell K, et al. "Secretoneurin is a secretogranin-2 derived hormonal peptide in vertebrate neuroendocrine systems." Gen Comp Endocrinol, 2020;299:113588. PMID: 32828813.
- [review] Trudeau VL, et al. "Is secretoneurin a new hormone?." Gen Comp Endocrinol, 2012;175(1):10-8. PMID: 22036841.
- [clinical-trial] Røsjø H, et al. "Trans-Cardiac Gradient of Secretoneurin in Patients with Takotsubo Syndrome." Cardiology, 2024;149(5):466-471. PMID: 38663366.
- [animal] Zhao E, et al. "The secretogranin II-derived peptide secretoneurin stimulates luteinizing hormone secretion from gonadotrophs." Endocrinology, 2009;150(5):2273-82. PMID: 19106223.
- [animal] Medhurst AD, et al. "Up-regulation of secretoneurin immunoreactivity and secretogranin II mRNA in rat striatum following 6-hydroxydopamine lesioning and chronic L-DOPA treatment." Neuroscience, 2001;105(2):353-64. PMID: 11672603.
- [mechanism] Wiedermann CJ, et al. "Secretoneurin and neurogenic inflammation." Zhongguo Yao Li Xue Bao, 1999;20(9):789-94. PMID: 11245085.
- [other] UniProt P13521 (SCG2_HUMAN), read November 6, 2026: secretoneurin is a ~33-amino-acid peptide cleaved from the central domain of secretogranin II, the product of the SCG2 gene and a member of the chromogranin/granin family. https://www.uniprot.org/uniprotkb/P13521/entry
- [other] Secretoneurin is the conserved central peptide produced by proteolytic processing of secretogranin II; the granin family (chromogranin A, chromogranin B and secretogranin II) and their derived peptides are reviewed in the granin-derived-peptides literature, and SN's biology is set out in the reviews carded on this page (read November 6, 2026).
- [other] US FDA, Drugs@FDA and the drug label endpoint (openFDA), searched November 6, 2026: no application and no label record for secretoneurin. It is an endogenous human peptide, not a registered drug; FDA GSRS and ChEMBL hold no substance record for it.
Sources & Citations
The six studies carded above were read from their PubMed records on November 6, 2026. Identity comes from UniProt (P13521, gene SCG2); secretoneurin's origin from secretogranin II, its granin-family relationships, its chemoattractant/angiogenic, neuroinflammatory, neuroendocrine (LH) and cardiac-biomarker roles, and the unidentified status of its receptor are from the reviews and studies carded here; the absence of US approval and of a drug substance record from Drugs@FDA, openFDA, FDA GSRS and ChEMBL was checked the same day. Grey Peptides sells nothing and links to no vendor.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Talk to a licensed clinician about your own situation.