Manserin
A 40-amino-acid peptide from the same granin protein as secretoneurin and EM66 — spread across the neuroendocrine system and a marker of prostate-cancer progression. A research peptide, not a drug
Manserin is a 40-amino-acid peptide cut from secretogranin II, one of the granins — the acidic proteins packed into the secretory granules of nerve and endocrine cells. The same precursor yields two other peptides this encyclopedia covers, secretoneurin and EM66, making manserin the third member of that family. First isolated from the rat brain in 2004, manserin turns up throughout the neuroendocrine system — the anterior pituitary, the hypothalamus and the adrenal gland — and a decade of careful mapping has since found it in a surprising range of tissues: the insulin- and somatostatin-making cells of the pancreas, the sound- and balance-sensing cells of the inner ear, the oxygen-sensing carotid body, the thyroid, the oviduct and the sensory neurons that carry pain signals, where it travels with the pain peptide CGRP. It is regarded as a stress-related neuroendocrine peptide, and in people its appearance in prostate-tumour tissue marks more aggressive, faster-progressing cancer. Manserin's exact signalling role is still being worked out; it is studied as a research peptide and a tissue marker, 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
Manserin is an endogenous secretogranin-II-derived peptide that has never been given to people as a treatment. The human study uses manserin as a tissue marker, and the rest of the work maps the body's own peptide in animals.
Work out syringe units → · New to syringes? · All dosing data ↓ · Dose and vial tracker · Is this vial OK?
What is it?
The granins are acidic proteins stored in the secretory granules of nerve and endocrine cells, where they are cut into many smaller active peptides. Secretogranin II (SgII) is one of them, and three of its products appear in this encyclopedia: secretoneurin, EM66 and manserin. Manserin is a 40-amino-acid peptide first isolated from the rat brain in 2004 and shown, like its siblings, to be generated by proteolytic processing of secretogranin II.
From the start manserin looked like a neuroendocrine peptide. It was found in the endocrine cells of the anterior pituitary (but not the posterior lobe) and in several hypothalamic nuclei and the median eminence, and — unlike its parent protein — it did not co-localise with the stress hormone ACTH, suggesting it is packaged and released in its own pattern and plays a distinct role in the neuroendocrine system.
Since then, detailed immunohistochemical mapping has placed manserin in a wide range of tissues. It occurs in the insulin-secreting beta cells and somatostatin-secreting delta cells of the pancreatic islets (but not the glucagon-making alpha cells); in the sound- and balance-sensing structures of the inner ear; in the oxygen-sensing glomus cells of the carotid body, where it may help regulate breathing; in the thyroid; in the oviduct, where it has been linked to stress-related gynaecological problems; and in a subset of small sensory neurons of the dorsal root ganglia, co-localised with the pain peptide CGRP and projecting to the pain-processing layers of the spinal cord — implicating manserin in nociception.
In humans, manserin has a diagnostic angle. In a study of prostate-cancer patients, the fraction of tumours staining positive for manserin rose with Gleason grade, and manserin-positive cancers progressed far faster than manserin-negative ones (a median of 8 versus 28 months), with manserin an independent predictor of progression. Like its SgII siblings secretoneurin and EM66, which are also linked to neuroendocrine tumours, manserin is of interest as a cancer marker.
Manserin is an endogenous secretogranin-II-derived research peptide and tissue marker. No published study has given manserin to people as a treatment — the human work is histochemical, and the rest is animal mapping — it is approved nowhere, and material sold online as 'manserin' 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
Manserin is a 40-amino-acid peptide cut from secretogranin II, alongside secretoneurin and EM66. It is a stress-related neuroendocrine peptide distributed across the pituitary, hypothalamus, pancreas, inner ear, carotid body and sensory neurons; its precise receptor and signalling mechanism are not yet established, but it is co-stored and co-released with other granin peptides and, in sensory neurons, with CGRP.
Secretogranin-II processing
Manserin is generated by proteolytic processing of secretogranin II — the same precursor as secretoneurin and EM66 — and is stored in the secretory granules of neuroendocrine cells (PMID 15257142).
Neuroendocrine and sensory signalling
Manserin is distributed across the pituitary, pancreatic islets, carotid body and inner ear (PMIDs 20495819, 29169693, 22034517) and is co-stored with CGRP in pain-signalling sensory neurons (PMID 34775224).
Tumour marking
In human prostate cancer, manserin expression rises with tumour grade and marks faster progression (PMID 21803620), echoing the links of its SgII siblings to neuroendocrine tumours.
Published Research
These are studies of manserin read from their PubMed abstracts on November 6, 2026. They include its discovery and characterisation as a secretogranin-II peptide in the neuroendocrine system, a human study of manserin as a prostate-cancer progression marker, and animal studies mapping it to the dorsal root ganglia (nociception), the endocrine pancreas, the carotid body and the inner ear. Manserin has not been given to people as a treatment; the human work is histochemical.
Discovery of manserin, a secretogranin-II peptide
A novel 40-amino-acid neuropeptide, named manserin, was isolated from the rat and shown to be generated by proteolytic processing of secretogranin II — like the previously described secretoneurin and EM66. Immunohistochemistry localised manserin to the endocrine cells of the anterior (not posterior) pituitary and to several hypothalamic nuclei and the median eminence, and showed it did not co-localise with ACTH, indicating a specific role in the neuroendocrine system (a characterisation study).
Manserin marks prostate-cancer progression
In 87 prostate-cancer patients, the manserin-positive rate rose with Gleason sum (0%, 20%, 35% and 48% for sums of 6, 7, 8 and ≥9), and among patients with T3/T4 disease, median time to progression was 8 months with manserin expression versus 28 months without. Manserin expression was an independent risk factor for progression — the first report of manserin in human prostate cancer and a potential marker of aggressive disease (a human observational study).
Manserin in sensory (pain) neurons
In rat dorsal root ganglia, manserin was localised to a subset of small CGRP-positive (peptidergic) sensory neurons — not the IB4-positive non-peptidergic ones — and these projected to the superficial pain-processing layers (I and II outer) of the spinal dorsal horn. The pattern suggests manserin is co-released with CGRP and participates in nociception (a preclinical result).
Manserin in the endocrine pancreas
In the rat pancreas, manserin immunoreactivity was found throughout the islets of Langerhans but not in the exocrine tissue. It co-localised with insulin-secreting beta cells and somatostatin-secreting delta cells — but not glucagon-secreting alpha cells — pointing to a potential role for manserin in the endocrine pancreas (a preclinical result).
Manserin in the oxygen-sensing carotid body
In the rat carotid body — the small organ that senses blood oxygen and helps control breathing — manserin was found specifically in the cytoplasm of the neuron-like glomus cells (tyrosine-hydroxylase-positive) and not in the glial-like sustentacular cells, suggesting a manserin secretion system that could help regulate respiration (a preclinical result).
Manserin in the inner ear
In the rat inner ear, manserin immunoreactivity was detected in the neuronal terminals of the organ of Corti and type II spiral ganglion cells of the auditory system, and at the synapses of the vestibular (balance) organs — the saccule, utricle and semicircular canals — suggesting manserin may contribute to peripheral hearing and balance (a preclinical result).
No Established Human Dose
Manserin is an endogenous secretogranin-II-derived peptide that has never been given to people as a treatment. The human study uses manserin as a tissue marker, and the rest of the work maps the body's own peptide in animals. No regulator has approved any dose, and no published human dose exists, so no amount is printed here.
What this rests on: PMID 15257142, PMID 21803620, PMID 34775224.
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 Manserin 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 Manserin 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 Manserin, 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 Manserin stays intact once mixed.
How it is taken
Unknown: with no established human dose, there is no established way of taking Manserin. 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 granin 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 Manserin. Results reported in the studies are under Published Research.
Source: half-life: PMID 15257142.
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 manserin to people; The human study uses manserin immunostaining as a prostate-cancer marker, not as a treatment (PMID 21803620); In animals it is mapped across many neuroendocrine and sensory tissues (PMIDs 20495819, 34775224) — a distribution, not a human safety profile; Material sold online as 'manserin' 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 Manserin. Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“Manserin is a research peptide and tissue marker that has not been given to people as a drug, so there is no human safety profile; the points below reflect that research status”).
Interactions
Unknown: a PubMed search for human interaction studies of Manserin (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 Manserin 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 manserin (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
Manserin is a research peptide and tissue marker that has not been given to people as a drug, so there is no human safety profile; the points below reflect that research status.
Contraindications & Cautions
Manserin has no approved use and no label. These points reflect its research status.
Legal Status
Manserin is an endogenous secretogranin-II-derived peptide studied as a research compound and tissue marker; it is not a drug and is not approved in any country.
Frequently Asked Questions
?What is manserin?
A 40-amino-acid peptide cut from secretogranin II — the same granin protein that yields secretoneurin and EM66. It was first isolated from the rat brain in 2004.
?What does it do?
Its exact signalling role is still being worked out, but it is a stress-related neuroendocrine peptide found across the pituitary, pancreas, inner ear, carotid body and pain-signalling sensory neurons (PMIDs 15257142, 34775224), and in humans it marks more aggressive prostate cancer (PMID 21803620).
?How is it related to secretoneurin and EM66?
All three are cut from the same precursor, secretogranin II, and are co-stored in secretory granules. Grey Peptides has separate entries for secretoneurin and EM66.
?Is it approved or available to buy?
No. Manserin is not a medicine, has no FDA application or label, and is approved nowhere; it is studied as a research peptide and a tissue marker. Material sold online as manserin is an unregulated research chemical. Grey Peptides lists no sellers and recommends no source; this page records the published science.
References
- [mechanism] Yajima A, et al. "Manserin, a novel peptide from secretogranin II in the neuroendocrine system." Neuroreport, 2004;15(11):1755-9. PMID: 15257142.
- [clinical-trial] Nishikawa K, et al. "Manserin as a novel histochemical neuroendocrine marker in prostate cancer." Urol Oncol, 2013;31(6):787-95. PMID: 21803620.
- [animal] Ida-Eto M, et al. "Localization of the neuropeptide manserin in rat dorsal root ganglia: Involvement in nociceptive function." Acta Histochem, 2021;123(8):151812. PMID: 34775224.
- [animal] Tano K, et al. "Manserin, a secretogranin II-derived peptide, distributes in the rat endocrine pancreas colocalized with islet-cell specific manner." Histochem Cell Biol, 2010;134(1):53-7. PMID: 20495819.
- [animal] Ida-Eto M, et al. "Specific localization of manserin peptide in the rat carotid body." Acta Histochem, 2018;120(1):11-14. PMID: 29169693.
- [animal] Ida-Eto M, et al. "Existence of manserin, a secretogranin II-derived neuropeptide, in the rat inner ear: relevance to modulation of auditory and vestibular system." J Histochem Cytochem, 2012;60(1):69-75. PMID: 22034517.
- [other] UniProt P13521 (secretogranin-2, SCG2 gene), read November 6, 2026: manserin is a 40-amino-acid peptide generated by proteolytic processing of secretogranin II, the same granin precursor that yields secretoneurin and EM66. https://www.uniprot.org/uniprotkb/P13521/entry
- [other] Manserin was isolated and named from the rat brain as a novel 40-residue peptide derived from secretogranin II, alongside the previously described secretoneurin and EM66; its sequence, neuroendocrine localisation and wider tissue distribution are from the studies 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 manserin. It is an endogenous secretogranin-II-derived 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, secretogranin-2) and the discovery study carded here: manserin's origin as a 40-residue secretogranin-II peptide alongside secretoneurin and EM66, its neuroendocrine localisation and wider tissue distribution (pancreas, inner ear, carotid body, sensory neurons), and its use as a prostate-cancer marker are from the studies carded on this page; 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.