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Steroids and sterols

alpha-Estradiol

Also known as 17alpha-Estradiol, Alfatradiol, 17a-estradiol

CAS 57-91-0Formula C18H24O2Molar mass 272.39 g/molEC 200-354-8
GHS signal word: Danger. Pictograms: Serious health hazard 28 suppliers listed
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alpha-Estradiol chemical structure, C18H24O2, CAS 57-91-0
2D chemical structure

Key facts

What buyers check first

All properties
CAS number
57-91-0
Formula
C18H24O2
Molar mass
272.39 g/mol
EC number
200-354-8
HS code
293723
Category
Steroids and sterols

What is alpha-Estradiol?

Plain description, key identifiers and synonyms

17alpha-estradiol is an estradiol that is estra-1,3,5(10)-triene substituted by hydroxy groups at positions 3 and 17 (the 17alpha stereoisomer). It has a role as a geroprotector and an estrogen. It is an estradiol, a 17alpha-hydroxy steroid and a 3-hydroxy steroid.

Identifiers

Registry numbers, names and line notations, tap to copy

IUPAC name
(8R,9S,13S,14S,17R)-13-methyl-6,7,8,9,11,12,14,15,16,17-decahydrocyclopenta[a]phenanthrene-3,17-diol
CAS number
57-91-0 CAS number cross-checked
EC number
200-354-8
Molecular formula
C18H24O2
UNII
3VQ38D63M7
MDL number
MFCD00064144
InChIKey
VOXZDWNPVJITMN-SFFUCWETSA-N
InChI
InChI=1S/C18H24O2/c1-18-9-8-14-13-5-3-12(19)10-11(13)2-4-15(14)16(18)6-7-17(18)20/h3,5,10,14-17,19-20H,2,4,6-9H2,1H3/t14-,15-,16+,17-,18+/m1/s1
Canonical SMILES
CC12CCC3c4ccc(O)cc4CCC3C1CCC2O
Isomeric SMILES
C[C@]12CC[C@H]3[C@H]([C@@H]1CC[C@H]2O)CCC4=C3C=CC(=C4)O

Synonyms

  • 17alpha-Estradiol
  • Alfatradiol
  • 17a-estradiol
  • 17-alpha-Estradiol
  • Estradiol-17alpha
  • 3,17-Dihydroxyestratriene
  • Epiestrol
  • 17-Epiestradiol
  • (8R,9S,13S,14S,17R)-13-methyl-6,7,8,9,11,12,14,15,16,17-decahydrocyclopenta[a]phenanthrene-3,17-diol
  • Estradiol, alpha-
  • Oestra-1,3,5(10)-triene-3,17alpha-diol
  • 3,17alpha-Dihydroxyestra-1,3,5(10)-triene
  • 3,17alpha-Dihydroxyoestra-1,3,5(10)-triene
  • alfatradiolum
  • (8R,9S,13S,14S,17R)-13-methyl-6,7,8,9,11,12,14,15,16,17-decahydrocyclopenta(a)phenanthrene-3,17-diol
  • Estradiol 17-alpha
  • (1S,10R,11S,14R,15S)-15-methyltetracyclo(8.7.0.02,7.011,15)heptadeca-2(7),3,5-triene-5,14-diol
  • Epiestradiol
  • 17|A-estradiol
  • Estra-1,3,5(10)-triene-3,17alpha-diol
  • a-Estradiol
  • 17alpha estradiol
  • (8R,9S,13S,14S,17R)-13-methyl-7,8,9,11,12,13,14,15,16,17-decahydro-6H-cyclopenta[a]phenanthrene-3,17-diol
  • 17alpha-Oestradiol
  • Oestradiol-17alpha
Show all 32 synonyms
  • Estradiol, 17alpha-
  • (17alpha)-estra-1,3,5(10)-triene-3,17-diol
  • Alpha-Estradiol (Standard)
  • 1,3,5-Estratriene-3,17a-diol
  • 17?-Estradiol
  • Alfatradiol (INN)
  • 1,3,5-Estratriene-3,17alpha-diol

Physical and chemical properties

Measured values and descriptors computed from the structure

Physical and chemical properties

Measured values, check the supplier specification for your grade

No measured properties are recorded for this substance yet. Ask suppliers for a technical data sheet.

Values vary by grade. Ask suppliers for the COA or TDS of the batch you buy.

Computed descriptors

Calculated from the structure, useful for screening and formulation

Molecular weight
272.39 g/molcalc.
Exact mass
272.1776 Dacalc.
LogP (octanol/water)
3.61calc.
Topological polar surface area
40.46 Ųcalc.
Hydrogen bond donors
2calc.
Hydrogen bond acceptors
2calc.
Rotatable bonds
0calc.
Heavy atoms
20calc.
Rings
4calc.
Aromatic rings
1calc.
Fraction sp3 carbons
0.67calc.
Formal charge
0calc.
Stereocentres
5calc.
Lipinski rule of five
Passes (0 violations)calc.

Calculated for screening. Confirm critical figures with the supplier.

Murcko scaffold

The ring system that remains when every side chain is removed

Murcko scaffold of this chemical, c1ccc2c(c1)CCC1C2CCC2CCCC21

c1ccc2c(c1)CCC1C2CCC2CCCC21

4 rings, 17 atoms.

585 other chemicals share this scaffold

Safety and hazards

GHS classification summary, not a safety data sheet

GHS signal word
Danger
GHS08: Serious health hazard
Serious health hazard

Hazard statements

  • H350May cause cancer.
  • H351Suspected of causing cancer.
  • H360May damage fertility or the unborn child.
  • H360FDMay damage fertility. May damage the unborn child.
  • H361Suspected of damaging fertility or the unborn child.
  • H362May cause harm to breast-fed children.
  • H372Causes damage to organs through prolonged or repeated exposure.
Precautionary statements (10)
  • P203Obtain, read and follow all safety instructions before use.
  • P260Do not breathe dust, fume, gas, mist, vapours or spray.
  • P263Avoid contact during pregnancy and while nursing.
  • P264Wash skin thoroughly after handling.
  • P270Do not eat, drink or smoke when using this product.
  • P280Wear protective gloves, protective clothing, eye protection and face protection.
  • P318If exposed or concerned, get medical advice.
  • P319Get medical help if you feel unwell.
  • P405Store locked up.
  • P501Dispose of contents and container in accordance with local regulations.

GHS classification summary, not a safety data sheet (SDS). Classifications can differ by supplier, grade and concentration. Always check the supplier's SDS.

Full safety data and first aid

alpha-Estradiol suppliers

Sponsored listings first, then the documented ranking: membership, verification, replies, completeness, freshness and ratings

All 28 suppliers
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Suppliers marked Unclaimed profile have not claimed their profile yet. They are not verified by CompoundList, their offers are price on request and details may have changed, so please confirm them with the supplier. Company representatives can claim a profile with a business email on the company's own website domain. Our team verifies each claim and sends the result by email.

Where suppliers are based

28 suppliers in 9 countries

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alpha-Estradiol price

Indicative price range per kg from live supplier offers

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Suppliers quote this chemical on request. Send one free request and compare quotes side by side.

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Uses and applications

What the substance is used for, by industry and function

Pharmacological actions

  • 5-alpha Reductase Inhibitors
  • Dermatologic Agents

Roles

  • agonist
  • estrogen
  • geroprotector
  • hormone
  • molecular messenger
  • pharmaceutical
  • protective agent
  • sex hormone

Regulatory status

Inventories, regulations and trade controls that list this substance

No regulatory list memberships are recorded for this substance yet. Always check the rules of the importing and exporting country before trade.

HS code and trade data

Customs classification and reported world trade statistics

Global trade

World import and export statistics for the HS code alpha-Estradiol is traded under.

HS 2937.23Indicative HS code

Oestrogens and progestogens

World exports in 2024
$762M
−2.3% vs 2023, imports $693M
2019 to 2024
Top exporters
  1. China42.9%
  2. Italy18.4%
  3. Netherlands8.9%
Top importers
  1. India * partner reported12.1%
  2. United States11.0%
  3. Belgium8.3%

* Partner reported figures, a lower bound.

Reported customs values in USD, not prices.Full trade data

The HS code shown for alpha-Estradiol is indicative (it was assigned by structure rules). Confirm the classification with your customs broker before shipping.

Frequently asked questions

Quick answers about alpha-Estradiol, based on the data on this page

What is alpha-Estradiol?

17alpha-estradiol is an estradiol that is estra-1,3,5(10)-triene substituted by hydroxy groups at positions 3 and 17 (the 17alpha stereoisomer). It has a role as a geroprotector and an estrogen. It is an estradiol, a 17alpha-hydroxy steroid and a 3-hydroxy steroid.

What is the CAS number of alpha-Estradiol?

The CAS registry number of alpha-Estradiol is 57-91-0.

What is the molecular formula and weight of alpha-Estradiol?

The molecular formula of alpha-Estradiol is C18H24O2 and its molar mass is 272.39 g/mol.

What is alpha-Estradiol used for?

Known uses and roles of alpha-Estradiol include agonist, estrogen, geroprotector, hormone, molecular messenger and 5 more.

Is alpha-Estradiol hazardous?

alpha-Estradiol carries the GHS signal word "Danger". Main hazards: may cause cancer, suspected of causing cancer, may damage fertility or the unborn child. This summary is not an SDS, always read the supplier safety data sheet.

What is the HS code of alpha-Estradiol?

alpha-Estradiol is usually classified under HS code 293723 (Oestrogens and progestogens). This is indicative, confirm it with your customs broker before shipping.

Where can I buy alpha-Estradiol?

CompoundList lists 28 suppliers of alpha-Estradiol in China, United States, Germany, Australia and 5 more. Send one free request to get and compare quotes. Your contact details stay private until you accept a quote.

What is the price of alpha-Estradiol?

Suppliers quote alpha-Estradiol on request because prices depend on grade, purity, quantity and destination. A free request on CompoundList gets you several quotes to compare.

Guides for buyers

Practical guides that help when you source, ship or handle alpha-Estradiol

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Data last updated 7 Oct 2026. Details may have changed, please confirm them with the supplier. Report an error on this page
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