The Women's Health Initiative (WHI) study used synthetic estrogen and progestin, not bioidentical hormones.

“And it was a sort of birth control pill style kind of hormone therapy. So a synthetic estrogen and uh uh progesterine, it was not sort of the what we call, you know, more um and we can talk about the marketing term bio identical, but the FDA approved products that we use today like estradiol and progesterone.”