Not all hormones are created equal.

A study on the connection between breast cancer and hormone replacement therapy (HRT) is making waves – again. It was just published two days ago and I’ve already been asked about it a lot.

The British Journal of Cancer showed a three times higher rate of breast cancer in women who took combined estrogen and progestogens (make a note of the word progestogen as I’ll bring it up in a bit). We have known for decades that combination HRT causes breast cancer. What’s new is how high the risk actually is. It’s 3 times higher! For a study with thousands of women that’s a big meaningful number.

The problem is that they lumped all kinds of progesterone together. The well-established bad synthetic kind (called proGESTIN) sourced from pregnant horses urine was NOT distinguished from the newer and safer yam sourced proGESTERONE (called Prometrium or just progesterone). ProGESTOGEN, which is the umbrella term for both synthetic progestin and natural progesterone, is what they looked at. Confusing, I know. But studies conflate them all the time. We really shouldn’t because they have very different effects. Progestins can cause breast cancer and natural progesterone has been shown to protect against it. Progesterone is even safer if it’s delivered in a topical cream that avoids processing by the liver. It’s important to talk to someone who knows these differences especially if you’re suffering from terrible symptoms of menopause and are concerned by scary news headlines.

Guardian Article: HRT Increases Breast Cancer

You can read the full study here