Conjugated estrogens (Premarin)

A mixture of estrogens purified from pregnant mares' urine, mainly sodium estrone sulfate and sodium equilin sulfate. They're used as HRT for hot flashes, vaginal atrophy and osteoporosis prevention, and sold as Premarin tablets and cream.

Premarin, as tablets and vaginal cream. Prempro and Premphase combine it with medroxyprogesterone, and Duavee combines it with bazedoxifene. Cenestin and Enjuvia are synthetic conjugated estrogens.

Yes. In November 2025 the FDA approved a generic version of Premarin (conjugated estrogens) tablets, the first in more than 30 years. The FDA said it should improve affordability and access, with the same quality, safety and effectiveness as the brand.

No. Estradiol is the main estrogen made by your ovaries. Premarin is mostly estrone and equilin sulfates from horses. Both treat hot flashes, but oral conjugated estrogens were linked to a higher clot risk than oral estradiol (odds ratio 2.08).

For blood clots, studies favor estradiol: it had a lower risk than conjugated estrogens in UK data (0.85 alone, 0.83 with a progestogen) and in US data. Estradiol also comes as patches and gels, which don't raise clot risk at all.

Moderate to severe hot flashes, vaginal and vulvar atrophy, and prevention of osteoporosis after menopause. If vaginal symptoms are the only problem, the label says a vaginal product should be considered first.

Premarin tablets come in 0.3 mg, 0.45 mg, 0.625 mg, 0.9 mg and 1.25 mg. Most women start at 0.3 mg daily for hot flashes, and the dose is adjusted by response.

Yes. The label describes it as conjugated estrogens purified from pregnant mares' urine. If you'd rather avoid animal-derived estrogen, estradiol tablets, patches and gels are alternatives, as are the synthetic conjugated estrogens Cenestin and Enjuvia.

In trials, the most common were abdominal pain, headache, back pain, weakness, gas, nausea, breast pain, insomnia, depression and vaginal discharge or bleeding. Report any unusual vaginal bleeding right away. Serious risks include clots, stroke and, with estrogen alone, endometrial cancer if you have a uterus.

Yes, if you have a uterus. Estrogen alone raises the risk of endometrial cancer, and adding a progestin lowers it. Prempro combines both in one tablet; Duavee uses bazedoxifene instead of a progestogen.

Yes, as of its June 2026 label. The FDA asked makers in November 2025 to remove boxed warnings on breast cancer, heart disease and dementia, and labels are being updated product by product.