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Clinical data
Synonyms EE3; 17α-Ethynylestriol; 17α-Ethynylestra-1,3,5(10)-triene-3,16α,17β-triol
Routes of
By mouth
Drug class Estrogen
CAS Number
PubChem CID
Chemical and physical data
Formula C20H24O3
Molar mass 312.41 g·mol−1
3D model (JSmol)

Ethinylestriol (EE3), or 17α-ethynylestriol, also known as 17α-ethynylestra-1,3,5(10)-triene-3,16α,17β-triol, is a synthetic estrogen which was never marketed.[1] Nilestriol, the 3-cyclopentyl ether of ethinylestriol, is a prodrug of ethinylestriol, and is a more potent estrogen in comparison,[1] but, in contrast to ethinylestriol, has been marketed.[2] Ethinylestriol has been found to reduce the risk of 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary cancer when given as a prophylactic in animal models, while other estrogens like ethinylestradiol and diethylstilbestrol were ineffective.[3]

See also


  1. ^ a b William McGuire (14 December 2013). Experimental Biology. Springer Science & Business Media. pp. 161–. ISBN 978-1-4757-4673-0.
  2. ^ J. Elks (14 November 2014). The Dictionary of Drugs: Chemical Data: Chemical Data, Structures and Bibliographies. Springer. pp. 891–. ISBN 978-1-4757-2085-3.
  3. ^ Lemon, Henry M. (15 December 1987). "Antimammary carcinogenic activity of 17-alpha-ethinyl estriol". Cancer. 60 (12): 2873–2881. doi:10.1002/1097-0142(19871215)60:12<2873::AID-CNCR2820601204>3.0.CO;2-B. ISSN 1097-0142. PMID 3119187.