Estradiol

Mechanism

Estradiol binds the nuclear oestrogen receptors ER-alpha and ER-beta, which act as ligand-activated transcription factors at oestrogen response elements in target tissue including uterus, vagina, breast, bone, and vascular endothelium. Circulating estradiol also exerts negative feedback on hypothalamic and pituitary gonadotrophin secretion, which is the basis of its labelled use in prostate cancer palliation. Route changes the exposure profile rather than the receptor: orally administered estradiol passes through the liver before reaching the systemic circulation and is substantially interconverted with estrone, whereas transdermal and vaginal administration bypass that first pass. Estradiol, estrone and estriol are cleared in the urine as glucuronide and sulfate conjugates.

Reported effects

What sources associate with this compound. Reported categories, not outcomes we have graded — each would need its own citation and rung.

• Moderate to severe vasomotor symptoms of the menopause - the indication the FDA labelling was granted for
• Moderate to severe vulvar and vaginal atrophy - labelled indication
• Hypoestrogenism from hypogonadism, castration or primary ovarian failure - labelled indication
• Prevention of postmenopausal osteoporosis - labelled indication
• Progression of carotid artery intima-media thickness: studied in the ELITE randomised placebo-controlled trial (n=643, oral 1 mg/day, median ~5 years), where progression was slower than placebo only in women randomised within 6 years of menopause and not in women 10 or more years past menopause
• Coronary atherosclerosis measured by CT (calcium, stenosis, plaque): studied in ELITE and did not differ significantly from placebo in either stratum
• Palliative treatment of advanced androgen-dependent prostate cancer and of metastatic breast cancer in selected patients - labelled indications

Half-life, storage & sport

Elimination half-life

161 min (mean; range 107-221 min) after removal of a 0.10 mg transdermal patch (human, transdermal) — study. Measured in 8 healthy postmenopausal women after removal of an abdominal-wall transdermal patch; clearance correlated with body weight. This figure describes the decay of transdermally delivered estradiol only. Half-life differs materially by route - oral, vaginal and intramuscular ester (estradiol valerate, estradiol cypionate) products have their own profiles, and the intramuscular esters are depots whose apparent half-life is dominated by release from the injection site, not by estradiol clearance. No route other than transdermal is quantified in this record.

Storage

not on file — no stability record found.

In sport (WADA)

not recorded as a yes or no — not established from the list document not established the list We could not open and read the WADA Prohibited List document itself, so no status is asserted here. What is recorded elsewhere in the List's section headings is that S4 covers hormone and metabolic modulators, with S4.1 aromatase inhibitors and S4.2 anti-oestrogenic substances (anti-oestrogens and SERMs) - substances that oppose oestrogen, which is not the same question as whether oestradiol itself appears. Treat this field as unread rather than as a negative finding.

The half-life on file is 2.7 h, measured transdermally. No dosing schedule could be read from this record, so the curve below is one dose drawn from the moment it is given. Nothing here says how often it is repeated.

The rise is not modelled and the axis is not a blood level. No absorption rate constant and no volume of distribution are on file, so each dose appears at full height the instant it is given, and the axis is percent of this compound's own peak.

Reported adverse effects

• Boxed warning on the FDA labelling: oestrogens increase the risk of endometrial cancer.

  reversibility not on file

• Boxed warning: cardiovascular disorders, probable dementia and breast cancer; the labelling states oestrogens with or without progestins should not be used for the prevention of cardiovascular disease.

  reversibility not on file

• Reported in >=10% of subjects in the transdermal system clinical trials: breast pain, upper respiratory tract infection, headache, abdominal pain, pain, and oedema.

  reversibility not on file

• Labelled adverse reaction categories for the tablets include cardiovascular events, malignancies, gastrointestinal effects, skin changes, central nervous system effects, genitourinary changes, and breast-related reactions.

  reversibility not on file

• In ELITE, serious adverse events occurred in 45 placebo and 43 estradiol participants; rates of breast cancer, myocardial infarction and thromboembolism did not differ significantly between groups. The trial was not powered for these events.

  reversibility not on file

Literature on file 5

• human RCT
  Vascular Effects of Early versus Late Postmenopausal Treatment with Estradiol (ELITE) graded on: names a randomised controlled trial — the indexed publication type — “Randomized Controlled”
• human observational
  Half-life of estradiol in postmenopausal women. Gynecol Obstet Invest, 1998 graded on: indexed as a clinical trial, design not stated — “Clinical Trial”
• human RCT
  FDA approval graded on: an FDA approval (), which requires adequate and well-controlled human investigations — “”

Not graded

2 citations whose study design could not be read from the title. Left ungraded rather than guessed at.

• not graded
  Estradiol Tablets USP - FDA prescribing information (DailyMed)
• not graded
  Estradiol Transdermal System - FDA prescribing information (DailyMed)

Identity

Also called

• oestradiol
• 17-beta-estradiol
• E2
• estradiol valerate
• estradiol hemihydrate

Listed prices 16

What 6 shops we track listed for Estradiol, read from their own public catalogues on 2026-09-14. We take no commission on these and they are not ranked by any payment — how vendors are scored.