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HRT / Estrogen (oestrogen)

Estrogen (oestrogen)

Estrogen is a family of hormones; estradiol and conjugated equine estrogens are different preparations. Research on menopausal HRT includes symptom relief, bone outcomes and longer-term risks. Interpretation depends on the formulation, route, age and population studied. Combined-hormone trial ↗ · Estrogen-alone trial ↗

Women: menopausal HRT

REPLENISH studied an oral estradiol–progesterone capsule for vasomotor symptoms and endometrial safety. WHI studied different oral preparations and major health outcomes. These answer different questions; neither should be described as a trial of every modern HRT regimen. Source ↗ · Source ↗

Men: physiology is not a replacement indication

An experimental study in men separated androgen and estrogen effects on body composition and sexual function. It is relevant background, but does not establish routine estrogen prescribing for male hypogonadism. Source ↗

Delivery methods & technical distinctions

Formulation / routeWhat the evidence tells us
Oral tabletsWHI used oral conjugated equine estrogen; REPLENISH used oral estradiol with progesterone. Identify the molecule and companion hormone, rather than grouping these as one treatment. Source ↗ · Source ↗
Skin patch / gelTransdermal estradiol avoids hepatic first-pass metabolism. In ESTHER, oral estrogen—but not transdermal estrogen—was associated with increased venous clot risk. ESTHER was observational: this is not proof that patches are risk-free. Australian product information ↗ · Source ↗
Vaginal cream / ringLocal vaginal treatment has been studied for recurrent urinary infections in postmenopausal women. Vaginal cream can still produce systemic absorption; product and exposure matter. It should not be treated as equivalent to skin gel. Source ↗ · US product label ↗
InjectionsNo head-to-head menopausal injection-versus-patch trial has been verified for this initial library. Comparative claims are withheld pending product-specific research.

Research library

Recent research plus older foundations · Trials, observational studies and product labels are separately identified · Phases shown only when verified

FOUNDATIONAL STUDY2015

Randomized trial ancillary study

KEEPS: cognition and mood in recently postmenopausal women ↗

Why it matters: Tests cognitive outcomes with oral and transdermal regimens closer to menopause.

No cognitive benefit was identified; this is not a dementia-prevention trial.

Abstract / record screened; full-text, conflicts and current correction checks pending.

FOUNDATIONAL STUDY2007

Case-control study

ESTHER: estrogen route, progestogens and venous thromboembolism ↗

Why it matters: Influential route-specific clot-risk research; foundational does not mean randomized.

Associations can be affected by confounding.

Abstract / record screened; full-text, conflicts and current correction checks pending.

FOUNDATIONAL STUDY2004

Randomized trial

WHI: estrogen alone after hysterectomy ↗

Why it matters: Major outcomes trial of oral conjugated equine estrogen in women without a uterus.

Higher stroke risk and fewer hip fractures; not evidence for universal disease prevention.

Abstract / record screened; full-text, conflicts and current correction checks pending.

FOUNDATIONAL STUDY2002

Randomized trial

WHI: estrogen plus progestin ↗

Why it matters: Landmark benefit–risk study that changed menopausal hormone prescribing.

Studied conjugated equine estrogen plus medroxyprogesterone acetate; not micronized progesterone.

Abstract / record screened; full-text, conflicts and current correction checks pending.

Last screened: 30 October 2026. This is an initial, non-exhaustive editorial library. Product labels are jurisdiction-specific; registration records are not a substitute for checking current Australian product information. No individualized treatment, dose conversion or self-administration protocol is provided.