Menopausal Hormone Therapy and Aging: What the Trials Show

What the US label approves

The Premarin label (revision of April 2025) lists treatment of moderate to severe hot flashes and night sweats (vasomotor symptoms) due to menopause among its uses, and states that estrogen plus progestin therapy should not be used for the prevention of cardiovascular disease or dementia. [1] Aging is not a listed use. Label: approved medicine for menopause symptoms and related conditions; not for preventing age-related disease.

The Women's Health Initiative (WHI) trials

The WHI randomized postmenopausal women aged 50 to 79 to hormones or placebo. Two arms are often confused:

• Estrogen plus progestin (16,608 women with a uterus). The trial was stopped early after a mean 5.2 years because breast cancer risk exceeded the stopping boundary. Hazard ratios: coronary heart disease 1.29, breast cancer 1.26, stroke 1.41, pulmonary embolism 2.13; fewer colorectal cancers (0.63) and hip fractures (0.66). Overall risks exceeded benefits, and all-cause mortality was not affected during the trial. [2]
• Estrogen alone (women who had a hysterectomy). Over about 6.8 years, estrogen increased stroke, decreased hip fracture and did not change coronary heart disease; the authors concluded it should not be recommended for chronic disease prevention. [3]
• Dementia. In women aged 65 and older, estrogen plus progestin doubled the hazard of probable dementia (hazard ratio 2.05). [4]
• Long-term follow-up. After years of follow-up, most risks and benefits faded after stopping, though some elevated breast cancer risk with combined therapy persisted. The authors said the findings do not support use for chronic disease prevention, although it is appropriate for symptom management in some women. [5]
• Deaths over 18 years. All-cause mortality was 27.1% with hormone therapy versus 27.6% with placebo in the pooled trials; no overall mortality difference. [6]

Label: established that hormone therapy should not be used to prevent chronic disease; no good evidence of benefit for lifespan.

Does timing matter? The ELITE trial

The "timing hypothesis" suggests that starting hormones soon after menopause may differ from starting years later. In ELITE, 643 healthy women were split by time since menopause. Oral estradiol slowed thickening of the carotid artery wall (a scan measure) in women under 6 years past menopause but not in women 10 or more years past it, and had no significant effect on heart CT measures in either group. [7] Label: promising but limited, and it is a scan measure, not a count of heart attacks.

The WHI authors also reported that estrogen-alone results were more favorable for women aged 50 to 59, a nominal finding. [5] The pooled mortality analysis found a lower relative mortality for younger than older women during the intervention. [6]

How the US labels changed

In November 2025 the US Food and Drug Administration (FDA) said it would start removing cardiovascular disease, breast cancer and probable dementia statements from the boxed warning on these products, while not seeking to remove the boxed warning for endometrial cancer in systemic estrogen-alone products. [8] In February 2026 it approved the first labeling changes for six products. [9] The FDA stated that randomized studies show women who start within 10 years of menopause onset have a reduction in all-cause mortality and fractures. [9] That statement differs from the WHI's overall mortality result above, so treat it as a regulator's summary, not a settled lifespan finding. The Premarin label we read predates these changes, so labels may differ by product and date.

What a professional society says

The North American Menopause Society (2022) says hormone therapy remains the most effective treatment for hot flashes and genitourinary symptoms and prevents bone loss. For women younger than 60 or within 10 years of menopause with no contraindications, it judged the benefit-risk balance favorable for bothersome symptoms and bone loss; for those starting later or older than 60, the balance looks less favorable because of greater absolute risks of coronary heart disease, stroke, venous thromboembolism and dementia. [10]

Related reading

See perimenopause and menopause, menopause, midlife hormone changes and healthy aging, bone health, osteoporosis and aging, and talking with a health professional. For plant products marketed for menopause, see botanicals for menopause and hormone claims.