≥98% (HPLC)

Empirical Formula (Hill Notation):
CAS Number:
Molecular Weight:
MDL number:
PubChem Substance ID:
Pricing and availability is not currently available.


≥98% (HPLC)




white to off-white


DMSO: >50 mg/mL



storage temp.


SMILES string




InChI key


Gene Information

human ... CYP19A1(1588)

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Letrozole has been used:
  • in organoid growth assay to determine its inhibitory capacity(48)
  • to investigate steroid receptor coactivator-1 (SRC-1) mediated endogenous estrogen regulation of hippocampal PSD-95(49)
  • to determine its effects on tumor-induced hyperalgesia(50)
  • for hormonal manipulation in rats(51)
  • to study its effects on lipocalin-2 (Lcn2)(52)
  • to determine its effects on mechanical hyperalgesia and aromatase expression(53)


10, 50 mg in glass bottle

Biochem/physiol Actions

Letrozole acts as an adjuvant agent and is used to treat breast cancer.
Letrozole is a third generation nonsteroidal aromatase inhibitor. It is a competitive inhibitor of the aromatase enzyme system and thus inhibits the conversion of androgens to estrogens. Letrozole inhibits the aromatase enzyme by competitively binding to the heme of the cytochrome P450 subunit of the enzyme, resulting in a reduction of estrogen biosynthesis in all tissues.

Features and Benefits

This compound was developed by Novartis. To browse the list of other pharma-developed compounds and Approved Drugs/Drug Candidates, click here.
This compound is featured on the Nuclear Receptors (Steroids) page of the Handbook of Receptor Classification and Signal Transduction. To browse other handbook pages, click here.


NONH for all modes of transport

WGK Germany


Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Certificate of Analysis
Certificate of Origin
Israel Ortega et al.
Fertility and sterility, 99(3), 889-896 (2012-12-04)
To evaluate the effects of letrozole on ovarian size and steroidogenesis in vivo, as well as on proliferation and steroidogenesis of theca-interstitial cells alone and in coculture with granulosa cells using an in vitro model. In vivo and in vitro studies. Research laboratory. Immature...
Drugs for Pregnant and Lactating Women E-Book (2009)
Pamela J Goodwin et al.
Journal of clinical oncology : official journal of the American Society of Clinical Oncology, 32(21), 2231-2239 (2014-06-18)
Obesity is associated with poor outcomes in women with operable breast cancer. Lifestyle interventions (LIs) that help women reduce their weight may improve outcomes. We conducted a multicenter randomized trial comparing mail-based delivery of general health information alone or combined...
G Allevi et al.
British journal of cancer, 108(8), 1587-1592 (2013-04-13)
The objective of this study was to determine the optimal scheduling of 2.5 mg daily letrozole in neoadjuvant breast cancer patients to obtain pathological complete response (pathCR) and assess Ki-67 expression as an early predictor of response. This single institution...
Richard S Legro et al.
The New England journal of medicine, 371(2), 119-129 (2014-07-10)
Clomiphene is the current first-line infertility treatment in women with the polycystic ovary syndrome, but aromatase inhibitors, including letrozole, might result in better pregnancy outcomes. In this double-blind, multicenter trial, we randomly assigned 750 women, in a 1:1 ratio, to...

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