What We Prescribe Instead: Premarin, MPA, and the Bioidentical Marketing Machine
We replaced one set of dogmas with another. Conjugated horse estrogen as the only option. MPA as the only progestogen.
Then “bioidentical” hormones as the cure for everything the WHI got wrong.
After the WHI, 80% of American women on hormone therapy stopped. The question became: for the women who still needed treatment for severe vasomotor symptoms, what should we prescribe?
The answer for 60 years had been simple. Premarin. Conjugated equine estrogen derived from pregnant mare urine. The name itself tells the origin story: Pregnant Mare Urine. It was the first commercially successful estrogen product (FDA-approved 1941), the best-selling drug in America by 1992, and the hormone used in the WHI.
Premarin was not just the default. It was the only option most clinicians knew. When a menopausal woman needed treatment, she got Premarin. When she needed endometrial protection, she got medroxyprogesterone acetate (MPA), Provera. Together: Prempro. One drug. One dose. One regimen. For every woman.
This one-size-fits-all approach ignored pharmacological reality. Premarin contains over 10 different estrogen compounds, some of which do not exist in the human body. MPA is a synthetic progestogen with a different receptor profile than endogenous progesterone. Oral administration of any estrogen undergoes hepatic first-pass metabolism, increasing clotting factor production and VTE risk.
Today we know that transdermal estradiol has a different risk profile than oral conjugated estrogen. We know that micronized progesterone has a different breast cancer risk profile than MPA. We know that route, formulation, and type all matter.
We also know that the “bioidentical” hormone industry exploited post-WHI fear to build a billion-dollar market on unregulated compounded products with no evidence of superiority and no standardization.
🎯 Free Subscriber Bottom Line: For 60 years, Premarin (conjugated equine estrogen) and MPA (medroxyprogesterone acetate) were the default and often only hormones prescribed for menopause. Evidence now shows that transdermal estradiol carries lower VTE risk, and micronized progesterone may carry lower breast cancer risk than MPA. Meanwhile, the compounded “bioidentical” hormone industry and salivary hormone testing have no evidence of superiority over regulated products and lack safety oversight.
Below, paid subscribers get: - Why Premarin is no longer the automatic default: transdermal vs oral evidence - The MPA problem: why the specific progestogen matters for breast cancer risk - The KEEPS and ELITE trials: what the “timing hypothesis” actually shows - Why routine FSH testing to “diagnose” menopause is clinically useless - The compounded bioidentical hormone industry: marketing vs evidence - Salivary hormone testing: why the Endocrine Society recommends against it - A prescribing framework based on current NAMS evidence.
