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    HomeMedication GuideEstradiol safety
    EstrogenFDA-Approved

    Estradiol: What to Know Before You Take It

    Also known as Estrace, Climara, Vivelle-Dot

    Other names: estradiol-hemihydrate, estradiol-hemihydrate, estradiol-cypionate, estradiol-valerate, injectable-estradiol, estrace, climara

    Estradiol is the primary endogenous estrogen and is FDA-approved in multiple forms including injectable formulations. Compounded injectable estradiol (as hemihydrate, cypionate, or valerate) is also available through licensed pharmacies for menopausal hormone therapy or transgender feminizing hormone therapy.

    FDA-approved injectable estradiol products exist (estradiol cypionate, estradiol valerate). Compounded estradiol hemihydrate is a common formulation used in clinical practice. FDA-approved oral and transdermal estradiol products are widely available.
    Reviewed by the OmniRx Health clinical team•Last reviewed Jul 4, 2026

    FDA boxed warning

    WARNING: ENDOMETRIAL CANCER, CARDIOVASCULAR DISORDERS, BREAST CANCER and PROBABLE DEMENTIA Estrogen-Alone Therapy Endometrial Cancer There is an increased risk of endometrial cancer in a woman with a uterus who uses unopposed estrogens. Adding a progestin to estrogen therapy has been shown to reduce the risk of endometrial hyperplasia, which may be a precursor to endometrial cancer. Adequate diagnostic measures, including directed or random endometrial sampling when indicated, should be undertaken to rule out malignancy in postmenopausal women with undiagnosed persistent or recurring abnormal genital bleeding [see WARNINGS, Malignant Neoplasms, Endometrial Cancer ]. Cardiovascular Disorders and Probable Dementia Estrogen-alone therapy should not be used for the prevention of cardiovascular disease or dementia [see CLINICAL STUDIES and WARNINGS, Cardiovascular Disorders, and Probable Dementia ]. The Women’s Health Initiative (WHI) estrogen-alone substudy reported increased risks of stroke and deep vein thrombosis (DVT) in postmenopausal women (50 to 79 years of age) during 7.1 years of treatment with daily oral conjugated estrogens (CE) [0.625 mg]-alone, relative to placebo [see CLINICAL STUDIES and WARNINGS, Cardiovascular Disorders ]. The WHI Memory Study (WHIMS) estrogen-alone ancillary study of WHI reported an increased risk of developing probable dementia in postmenopausal women 65 years of age or older during 5.2 years of treatment with daily CE (0.625 mg)-alone, relative to placebo. It is unknown whether this finding applies to younger postmenopausal women [see CLINICAL STUDIES and WARNINGS, Probable Dementia and PRECAUTIONS, Geriatric Use ]. In the absence of comparable data, these risks should be assumed to be similar for other doses of CE and other dosage forms of estrogens. Estrogens with or without progestins should be prescribed at the lowest effective doses and for the shortest duration consistent with treatment goals and risks for the individual woman. Estrogen Plus Progestin Therapy Cardiovascular Disorders and Probable Dementia Estrogen plus progestin therapy should not be used for the prevention of cardiovascular disease or dementia [see CLINICAL STUDIES and WARNINGS, Cardiovascular Disorders, and Probable Dementia ]. The WHI estrogen plus progestin substudy reported increased risks of DVT, pulmonary embolism (PE), stroke and myocardial infarction (MI) in postmenopausal women (50 to 79 years of age) during 5.6 years of treatment with daily oral CE (0.625 mg) combined with medroxyprogesterone acetate (MPA) [2.5 mg], relative to placebo [see CLINICAL STUDIES and WARNINGS, Cardiovascular Disorders ]. The WHIMS estrogen plus progestin ancillary study of the WHI reported an increased risk of developing probable dementia in postmenopausal women 65 years of age or older during 4 years of treatment with daily CE (0.625 mg) combined with MPA (2.5 mg), relative to placebo. It is unknown whether this finding applies to younger postmenopausal women [see CLINICAL STUDIES and WARNINGS, Probable Dementia and PRECAUTIONS, Geriatric Use ]. Breast Cancer The WHI estrogen plus progestin substudy also demonstrated an increased risk of invasive breast cancer [see CLINICAL STUDIES and WARNINGS, Malignant Neoplasms, Breast Cancer ]. In the absence of comparable data, these risks should be assumed to be similar for other doses of CE and MPA, and other combinations and dosage forms of estrogens and progestins. Estrogens with or without progestins should be prescribed at the lowest effective doses and for the shortest duration consistent with treatment goals and risks for the individual woman.

    In plain language

    What Estradiol is used for

    • Menopausal hormone therapy (hot flashes, bone protection)
    • Transgender feminizing hormone therapy
    • Hypogonadism in females

    Taking this medicine

    How it is administered

    • Subcutaneous injection
    • Intramuscular injection

    Read before you decide

    Risks and precautions

    Risks and warnings

    • Nausea, bloating, breast tenderness
    • Irregular periods or spotting
    • Mood changes
    • Blood clot risk (VTE)

    Who should not take it

    • Estrogen-receptor-positive breast cancer
    • History of blood clots or clotting disorder
    • Undiagnosed vaginal bleeding

    Medication review

    Estradiol drug interactions

    Estradiol + AtorvastatinOral Contraceptives: May increase plasma levels of norethindrone and ethinyl estradiol; consider this effect when selecting an oral contraceptive (7.3 ).Moderate interactionEstradiol + TacrolimusMild or Moderate CYP3A Inhibitors: Clotrimazole, antibiotics (e.g., verapamil, diltiazem, nifedipine, nicardipine), amiodarone, danazol, ethinyl estradiol, cimetidine, lansoprazole and omeprazole May increase tacrolimus whole blood trough concentrations and increase the risk of serious adverse reactions (e.g., neurotoxicity, QT prolongation) [see Warnings and Precautions ( 5.7 , 5.10 , 5.11 )] .Moderate interactionEstradiol + AmoxicillinFollowing administration of ampicillin or amoxicillin to pregnant women, a transient decrease in plasma concentration of total conjugated estriol, estriol-glucuronide, conjugated estrone, and estradiol has been noted.Minor interactionEstradiol + Amoxicillin ClavulanateFollowing administration of amoxicillin to pregnant women, a transient decrease in plasma concentration of total conjugated estriol, estriol-glucuronide, conjugated estrone, and estradiol has been noted.Minor interactionEstradiol + ColchicineDrug Interactions: Pharmacokinetic Parameters for Colchicine Tablets in the Presence of the Coadministered Drug Coadministered Drug Dose of Coadministered Drug (mg) Dose of Colchicine Tablets (mg) N % Change in Colchicine Concentrations from Baseline (Range: Min – Max) C max AUC 0-t Cyclosporine 100 mg single dose 0.6 mg single dose 23 270.0 (62.0 to 606.9) 259.0 (75.8 to 511.9) Clarithromycin 250 mg twice daily, 7 days 0.6 mg single dose 23 227.2 (65.7 to 591.1) 281.5 (88.7 to 851.6) Ketocon…Minor interactionEstradiol + FluconazoleThere was no significant difference in ethinyl estradiol or levonorgestrel AUC after the administration of 50 mg of fluconazole.Minor interactionEstradiol + GabapentinOral Contraceptive Based on AUC and half-life, multiple-dose pharmacokinetic profiles of norethindrone and ethinyl estradiol following administration of tablets containing 2.5 mg of norethindrone acetate and 50 mcg of ethinyl estradiol were similar with and without coadministration of gabapentin (400 mg three times a day; N=13).Minor interactionEstradiol + ModafinilAlternative or concomitant methods of contraception are recommended for patients taking steroidal contraceptives (e.g., ethinyl estradiol) when treated concomitantly with modafinil and for one month after discontinuation of modafinil treatment.Minor interactionEstradiol + PravastatinIn a placebo-controlled study of 214 pediatric patients with HeFH, of which 106 were treated with pravastatin (20 mg in the children aged 8-13 years and 40 mg in the adolescents aged 14-18 years) for 2 years, there were no detectable differences seen in any of the endocrine parameters (ACTH, cortisol, DHEAS, FSH, LH, TSH, estradiol [girls] or testosterone [boys]) relative to placebo.Minor interactionEstradiol + TestosteroneFree hormone concentrations, such as testosterone and estradiol, may be decreased.Minor interaction
    Check this against your full medication list in the Interaction Checker

    FDA safety data

    Most-reported side effects

    Based on 190,011 FAERS reports. Reports do not prove the drug caused the effect.

    pain 19,106pulmonary embolism 14,351injury 11,771deep vein thrombosis 11,712nausea 11,492drug ineffective 11,382anxiety 11,297headache 10,492off label use 9,403fatigue 8,789product adhesion issue 7,501emotional distress 7,003
    Explore full FDA safety data

    Regulatory record

    FDA recalls (20)

    Class IIOngoing · May 27, 2026

    Failed Impurities/Degradation Specifications: This recall is being initiated due to out-of-specification results total impurities.

    Recalling firm: Glenmark Pharmaceuticals Inc., USA

    Class IIOngoing · May 12, 2026

    Defective Container; packets were found to be either empty or partially full.

    Recalling firm: ANI Pharmaceuticals, Inc.

    Class IIOngoing · Sep 3, 2025

    Failed Impurities/Degradation Specifications

    Recalling firm: Glenmark Pharmaceuticals Inc., USA

    Class IIOngoing · Sep 2, 2025

    Failed Content Uniformity Specifications

    Recalling firm: AvKARE

    Class IIIOngoing · May 16, 2024

    Failed Impurities/Degradation Specifications.

    Recalling firm: Zydus Pharmaceuticals (USA) Inc

    Class IIIOngoing · May 16, 2024

    Failed Impurities/Degradation Specifications.

    Recalling firm: Zydus Pharmaceuticals (USA) Inc

    Class IITerminated · Mar 7, 2024

    Failed Dissolution Specifications

    Recalling firm: Teva Pharmaceuticals USA, Inc

    Class IIIOngoing · Jan 25, 2024

    Discoloration: discolored tablets (shades of blue) mixed in with the white inert remainder tablets.

    Recalling firm: Teva Pharmaceuticals USA, Inc

    Class IIIOngoing · Jan 25, 2024

    Discoloration: discolored tablets (shades of blue) mixed in with the white inert remainder tablets.

    Recalling firm: Teva Pharmaceuticals USA, Inc

    Class ITerminated · Jun 23, 2023

    Failed Stability Specification and Failed Impurities/Degradation Specifications: out of specification for inactive content ascorbic acid and MTHFRC-7impurity test

    Recalling firm: Lupin Pharmaceuticals Inc.

    Class IIIOngoing · Feb 21, 2023

    Failed Content Uniformity Specifications: The Spray Content Uniformity (SCU) requirement for Standard Deviation did not meet the requirement at the 18-month stability time point.

    Recalling firm: Padagis US LLC

    Class IITerminated · Jan 26, 2022

    CGMP Deviations: Products were exposed to temperatures outside of the products labeled storage conditions.

    Recalling firm: CARDINAL HEALTHCARE

    Common questions

    Patient questions

    Is injectable estradiol better than oral?

    Injectable estradiol bypasses first-pass liver metabolism, which may reduce some VTE and metabolic risks compared to oral forms. This is an area of ongoing research. A licensed provider evaluates which form and route is most appropriate based on your health history.

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    This information is educational — not medical advice.

    This page is provided for general educational purposes and summarizes publicly available data from sources such as the U.S. Food & Drug Administration. It is not a substitute for the judgment of a licensed clinician and should not be used to start, stop, or change any medication. It may be incomplete or out of date, and individual circumstances vary. Always talk with your prescriber or pharmacist about your specific medications and health conditions. If you think you may have a medical emergency, call 911.

    Have medication questions?

    A licensed OmniRx provider can review your health history and medication list. Availability and treatment options are determined individually.