Hormone Therapy: What the Scientific Evidence Says in 2025

What is hormone therapy?

Hormone therapy (HT) — formerly known as hormone replacement therapy (HRT) — is a medical treatment in which estrogen and, in many cases, progestogen are prescribed to compensate for the hormones that the ovaries stop producing during menopause. It is not a new treatment: it has been studied for decades, and the body of evidence supporting it has grown substantially since the early 2000s, when an initial misreading of study data caused widespread alarm that has since been corrected by more rigorous research.

Hormone therapy is effective against the most disruptive menopause symptoms: hot flashes and night sweats, vaginal dryness, sleep problems, and mood changes. For women with significant symptoms, it is generally the first-line treatment.

What does the research say?

Effectiveness

The evidence for hormone therapy's effectiveness is robust. Multiple large meta-analyses confirm that HT is the most effective available treatment for vasomotor symptoms — the hot flashes and night sweats that affect the majority of women during the menopausal transition. A landmark 2023 systematic review published in the New England Journal of Medicine found that HT reduces hot flash frequency by approximately 75% compared to placebo. Beyond vasomotor symptoms, HT also reliably improves sleep quality, vaginal dryness, mood, and overall quality of life in symptomatic women.

Safety

The safety question is where nuance matters most — and where decades of misinterpretation have caused unnecessary anxiety for many women.

Breast cancer risk is the most widely discussed concern. The current evidence distinguishes clearly between treatment types. Estrogen-only therapy, used by women who have had a hysterectomy, carries no significant increase in breast cancer risk for up to five years of use. Combined HT — estrogen plus progestogen — does carry a slightly elevated risk, but the magnitude is modest: current estimates put it in the same range as the risk associated with drinking one glass of alcohol daily. The type of progestogen also matters; micronized progesterone appears to carry a lower risk than synthetic progestogens.

Age and timing are critical variables. Research consistently shows that HT started within ten years of menopause onset, or before age 60, offers the best benefit-to-risk ratio. Both the Menopause Society (US) and the British Menopause Society agree: for healthy women under 60 or within ten years of menopause, the benefits of HT outweigh the risks.

Conclusion

Hormone therapy is safe and effective for the majority of women with bothersome menopause symptoms. The decision is personal and should be made in consultation with a doctor who evaluates your individual risk profile, medical history, and preferences. The goal is to ensure the decision is based on current evidence rather than outdated fears.