There’s two general categories of hormone therapy. There’s what we call estrogen-alone therapy. Estrogen-alone therapy is given to women who do not have a uterus. Women with a uterus need a form of progesterone, so if it’s synthetic, we call it a progestin. They need a form of that to protect the uterine lining against cancer and the addition of that progestin to the estrogen completely takes away the increased risk for that form of cancer, so that’s why women need it. Hysterectomized women need estrogen-alone, whereas women with a uterus need estrogen, plus progestin.
Then the next decision is what form of estrogen women might take. The safest approach to getting what’s called bioidentical hormone therapy, or a form of estrogen that’s most similar to that which our ovaries produce, is trying 17 beta-estradiol, which many practitioners recommend and is available in a patch and a pill.
The second decision for women with a uterus is what form of progesterone they might want to use. Many providers recommend [a natural progesterone called] micronized progesterone because it is like 17 beta-estradiol in that it is most similar to what women naturally produce. There are however a variety of different synthetic progestins. Many women are exposed to these in the form of oral contraceptives or birth control pills and those are also known to be safe options for women.