Clinical comparison · Menopause & vasomotor symptoms · Updated 2026-07-02
Estradiol and conjugated equine estrogens are two estrogen preparations used in menopausal hormone therapy. This table reproduces labeled and trial-reported facts verbatim, per cell. It makes no claim that one preparation is superior — the choice is individualized with a prescriber.
Every value below is reproduced verbatim from an FDA prescribing-information document or a published clinical trial, and each cell links to its source. This page does not rank the two options, does not declare one safer or more effective, and is not medical advice.
| Dimension | Estradiol (17-beta-estradiol) | Conjugated equine estrogens (CEE) |
|---|---|---|
| Estrogen composition | Single molecule: 17-beta-estradiol (bioidentical)[1] | Mixture of conjugated estrogens from equine source[2] |
| Available routes | Transdermal patch, gel, oral tablet, vaginal[3] | Oral tablet; vaginal cream[2] |
| Route-specific VTE signal | Transdermal estradiol: no significant increase in VTE risk vs non-use[4] | Oral estrogen route associated with increased VTE risk vs non-use[4] |
| WHI estrogen-alone finding (CEE) | Not the agent studied in the WHI estrogen-alone arm[1] | Reduced fracture risk; no increase in breast cancer in the hysterectomy cohort[2] |
| Pregnancy category | Contraindicated in pregnancy (FDA category X)[3] | Contraindicated in pregnancy (estrogen class)[2] |
What the WHI estrogen-alone arm measured
The Women's Health Initiative estrogen-alone trial randomized women with prior hysterectomy to conjugated equine estrogens or placebo. It reported reduced fracture risk and no increase in breast cancer in that cohort. Findings apply to CEE in that specific population. WHI estrogen-alone (JAMA 2004)
Why VTE is shown by route
The BMJ 2019 cohort separated oral and transdermal estrogen. Because CEE is used orally and estradiol is available transdermally, the VTE signals shown reflect route as much as molecule. Transdermal vs oral VTE (BMJ 2019)
No. Estradiol is a single bioidentical molecule (17-beta-estradiol), while conjugated equine estrogens are a mixture of estrogens from an equine source (NAMS 2022; WHI 2004).
In women with prior hysterectomy taking conjugated equine estrogens, it reported reduced fracture risk and no increase in breast cancer in that cohort (JAMA 2004).
Editorial reviews from ClearHormones of telehealth providers in this category. These are not treatment recommendations, and prescribing decisions rest with a licensed clinician.