A new study presented at the 2025 Annual Meeting of The Menopause Society suggests that starting hormone therapy during perimenopause may offer the greatest long-term health benefits. Researchers analyzed data from more than 120 million patient records and found that women who began estrogen therapy during perimenopause and continued it for at least ten years had about a 60% lower risk of developing breast cancer, heart attack, or stroke. This compares to women who started hormone therapy later or never used it at all.
Perimenopause is the hormonal transition period leading up to menopause. It can begin in a woman’s mid-to-late 30s or 40s and is marked by changes such as less restorative sleep, mood shifts, or unpredictable menstrual cycles. The study divided women into three groups: those who started estrogen therapy during perimenopause and continued for at least a decade before menopause, those who began hormone therapy after menopause, and those who never used hormones.
The results showed that women who started therapy early had about 60% lower odds of developing all three conditions. Women who began estrogen therapy after menopause showed only minimal protective effects. The study also found a slight increase in stroke risk, about 4.9% higher, for those who started therapy after menopause compared to those who never used hormones.
Estrogen plays a role beyond reproduction. It affects metabolic, cardiovascular, and cognitive health. In the heart, it helps keep blood vessels flexible and supports healthy cholesterol levels. In the brain, it promotes neuroplasticity and supports serotonin and dopamine balance. In bones and muscles, it helps preserve density and strength. When estrogen is introduced early, before these systems decline, it may help preserve their function. Waiting until after menopause, when estrogen receptors have been without stimulation for years, may not deliver the same benefits.
Implications for women in their 30s and 40s
Women experiencing signs of hormonal transition, such as shorter cycles, sleep changes, mood fluctuations, or increased anxiety, may want to talk to a healthcare provider. The research suggests that earlier intervention may lead to better long-term outcomes. Perimenopause can begin as early as the mid-to-late 30s. Tracking cycles, symptoms, and energy levels can help identify changes.
Finding a provider who understands menopause and hormone health is important. A clinician can personalize therapy based on symptoms, health history, and timing. Healthy lifestyle habits, including strength training, balanced nutrition, sleep optimization, and stress management, also support any hormone therapy plan.
The study adds to evidence that the timing of hormone therapy may be a key factor. Starting estrogen during perimenopause may help protect the heart, brain, and bones for years to come. The findings reinforce the idea that earlier may be better for optimizing long-term health outcomes.
