Estradiol

Transdermal estradiol reliably improves hot flashes, vaginal dryness, and bone density. Estrogen use for as few as 5 years reduced ovarian, uterine, lung, and colorectal cancer by 33%. In the Medicare study, mortality reduction was greater with estradiol than with conjugated equine estrogens. Estradiol binds both estrogen alpha and beta receptors and is not associated with the inflammatory or cardiovascular effects of conjugated equine estrogens. Conjugated equine estrogens bind primarily to estrogen beta receptors, increasing inflammatory markers, contributing to collagen breakdown, and promoting plaque destabilization.