Bone of Contention

Last week, I got salty about the “lowest effective dose” adage, the phrase we paste onto our tongues like it’s required by law any time estrogen comes up. I showed you the evidence for lower doses being safer if you’re worried about breast cancer, heart disease, stroke, and clots. Spoiler: for most of those, there isn’t any.

Here is that article.

Today is about why I got so salty. Why do I care if your doctor put you on a 0.025 patch and never mentioned there was a bigger one? Why do I care if you don’t care?

Because your bones care.

Yes, a little estrogen helps bone. It does. And yes, we can decide to dose by symptoms alone and call it a day. But both of those dodge the same inconvenient finding: when it comes to bone density, more estrogen builds more bone than less estrogen. In a world full of people insisting that size doesn’t matter, here I come, bull in a china shop, to tell you that in this one specific case, it really, really does.

So let’s talk about what the trials show.

Oral conjugated equine estrogens. Oral micronized estradiol. Transdermal estradiol. Esterified estrogens. Estradiol valerate. Across thirty-nine randomized trials in one systematic review, virtually every estrogen regimen maintained or increased bone density at the spine and hip, with no compound clearly beating another at equivalent exposure. This is a class effect. Estrogen tells osteoclasts to calm down, and osteoclasts listen regardless of which molecule delivered the message.

Which makes “is my estrogen the right kind” mostly the wrong question for bone. The better one is “how much?”