Shocking new discovery on hormone therapy turns conventional wisdom on its head

The study I want to share with you today took me completely by surprise. In fact, it’s made me reflect on the way I recommend and prescribe hormone replacement therapy (HRT) in women.

Now, what I’m about to tell you goes against almost everything we’ve learned throughout the years about estrogen replacement therapy. But as you’ll see, it’s a significant finding by any standard.

So, let’s dive right in…

Turning the tables

This latest research is based on nearly two decades of follow-up from the Women’s Health Initiative. And it found that the effects of HRT on breast cancer risk depends on whether you use estrogen alone, or estrogen plus progestin.

In fact, findings showed that using estrogen alone (made from horse urine) dropped the risk of breast cancer incidence and death significantly. While adding progestin (in the form of medroxyprogesterone acetate) increased that risk by nearly the same amount.

In this study, women with a uterus took estrogen plus progestin or a placebo every day for a median of 5.6 years. Women without a uterus took estrogen alone or a placebo for a median of 7.2 years.

After roughly 19 years of follow-up, researchers found that estrogen alone decreased breast cancer risk by 23 percent—while estrogen plus progestin raised the risk by nearly 30 percent. Breast cancer deaths, meanwhile, increased by 45 percent with estrogen and progestin… and dropped by 44 percent with estrogen alone.

This goes against everything we have always been taught—that is, to never give estrogen alone to patients, because it increases the risk for hormone-related cancers.

But perhaps it’s not so simple?

Needless to say, this research has given me pause.

Weighing the risks and benefits

Another thing that makes these findings so shocking is that half a century of research on the subject still hasn’t settled the controversy over HRT’s relationship to breast cancer risk. And results from both observational studies and controlled trials still aren’t consistent.

For instance, one meta-analysis of nearly 60 observational studies linked both types of HRT regimens to significant increases in breast cancer risk. Another analysis—the Million Women Study—linked both regimens with significant increases in risk of breast cancer death.

So what to do with this latest finding? Well, the study’s lead author thinks women should know that estrogen alone is safer—and possibly even beneficial against breast cancer. And that, if you choose estrogen plus progestin, you should be prepared to accept the increase in risk that comes with it.

In both instances, the impact can last decades after stopping the hormones. At least 20 years… and possibly for a lifetime.

Of course, it’s worth noting that this new research used synthetic hormones. So it’s impossible to say whether the results would apply to bio-identical HRT (which is the only kind I recommend, anyway).

Like I said, I’m still processing this information for myself. For now, at least, my recommendations won’t be changing. Because there is vast evidence supporting the use of bio-identical hormone therapy over conventional hormone therapy (made from horse urine). (And you shouldn’t have to risk disfigurement and disability just to get a break from hot flashes and a decent night’s sleep.)

Nevertheless, knowledge is power. So if you or someone you love is currently on HRT, or simply considering it, any new information deserves your attention. And you can always count on me to deliver it—right here in my Reality Health Check, and in my monthly Logical Health Alternatives newsletter.


“’Remarkable’ New Data on Menopausal Hormone Therapy.” Medscape Medical News, 12/13/2019. (