Cyproheptadine hydrochloride sesquihydrate

≥98% (TLC), solid

Piperidine, 4-(5H-dibenzo[a,d]cyclohepten-5-ylidene)-1-methyl-, hydrochloride, hydrate (2:3)
Empirical Formula (Hill Notation):
CAS Number:
Molecular Weight:
EC Number:
PubChem Substance ID:
Pricing and availability is not currently available.

Quality Level


≥98% (TLC)




white to slightly yellow


ethanol: soluble
methanol: soluble


Merck & Co., Inc., Kenilworth, NJ, U.S.

SMILES string




InChI key


Gene Information

human ... HRH1(3269), HTR2A(3356), HTR2B(3357), HTR2C(3358)

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Cyproheptadine hydrochloride sesquihydrate has been used in:
  • testing anti-inflammatory activity in serotonin receptor (5-HT) induced inflammation
  • the inhibition of 5-HT in in vivo and in vitro bioassays in crabs
  • the inhibition of 5-HT in embryo physiological experiments

inhibition of calcitonin gene related peptide (CGRP)


100 mg in poly bottle
1 g in poly bottle

Biochem/physiol Actions

Cyproheptadine hydrochloride sesquihydrate is a serotonin receptor (5-HT2/5-HT1C) antagonist, H1 histamine receptor antagonist and an antipruritic. The inhibition of 5-HT by cyproheptadine improves cognitive function in schizophrenia disorder. Cyproheptadine is effective for treating functional gastrointestinal disorders (FGIDs). Food and Drug Administration (FDA) approved cyproheptadine, has antidepressant and antiplatelet functionality. It may be effective in treating thromboembolic disorders. Cyproheptadine inhibits lysine methyltransferase 7/9 (Set7/9) leading to a decrease in estrogen receptor (ERα) expression and growth arrest in breast cancer cells.

Features and Benefits

This compound was developed by Merck & Co., Inc., Kenilworth, NJ, U.S.. To browse the list of other pharma-developed compounds and Approved Drugs/Drug Candidates, click here.
This compound is also offered as part of Sigma′s Library of Pharmacologically Active Compounds (LOPAC®1280), a biologically annotated collection of high-quality, ready-to-screen compounds. Click here to learn more.

Legal Information

LOPAC is a registered trademark of Sigma-Aldrich Co. LLC


Skull and crossbones

Signal Word


Hazard Statements

Target Organs

Respiratory system

Personal Protective Equipment

dust mask type N95 (US),Eyeshields,Gloves


UN 2811 6.1 / PGIII

WGK Germany


Certificate of Analysis
Certificate of Origin
Identification of cyproheptadine as an inhibitor of SET domain containing lysine methyltransferase 7/9 (Set7/9) that regulates estrogen-dependent transcription
Takemoto Y, et al.
Journal of Medicinal Chemistry, 59(8), 3650-3660 (2016)
E O Okoro
The Journal of pharmacy and pharmacology, 51(8), 953-957 (1999-09-30)
We have previously shown that elimination of buffer Ca2+ markedly reduced maximum 5-HT-induced contractions. We have now investigated the effect of L-type Ca2+-channel blockers and 5-HT2 receptor antagonists on 5-HT- and K+-induced contractions in rat aorta to explore the possibility...
Cyproheptadine: a potentially effective treatment for functional gastrointestinal disorders in children
Krasaelap A and Madani S
Pediatric Annals, 46(3), e120-e125 (2017)
Effects of the 5HT antagonist cyproheptadine on neuropsychological function in chronic schizophrenia
Chaudhry IB, et al.
Schizophrenia Research, 53(1-2), 17-24 (2002)
Anti-inflammatory activity of bartogenic acid containing fraction of fruits of Barringtonia racemosa Roxb. in acute and chronic animal models of inflammation
Patil KR and Patil CR
Journal of traditional and complementary medicine, 7(1), 86-93 (2017)

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