Estradiol

Estradiol (E2) is the most biologically active estrogen. Before menopause, it is made mainly in the ovaries. Smaller amounts come from converting androgens, a process called aromatization. That conversion happens in fat, brain, bone, liver, breast, and other tissues. The hormone supports several things. It supports your blood-vessel function, bone turnover, and reproductive tissues. It may support cognition too. After menopause, levels drop sharply. The remaining supply then comes from peripheral aromatization. That drop speeds bone loss and brings hot flashes. It also drives a multi-factor rise in heart-and-metabolic risk. In men, a modest amount (from aromatization) is important for bone health.

Last reviewed: June 22, 2026

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