Estradiol, Bone and Heart Health: Why “The Numbers Don’t Matter” Is No Longer Good Enough

For years, women have been told that when it comes to menopausal hormone therapy, the numbers don't matter for bone and heart health.

I think we need to rethink that.

Medicine changes. Evidence evolves. And guidelines, by their nature, often move more slowly than the science.

Menopause care is one of the clearest examples.

After the Women's Health Initiative was released in 2002, hormone therapy went from being widely prescribed to something many women were frightened to take. The practical message became: use as little as possible, for as short a time as possible.

We now understand that the story was far more complicated.

The type of estrogen matters.

The type of progesterone matters.

The route of administration matters.

The age at which treatment is started matters.

The number of years since menopause matters.

And most importantly, the individual woman matters.

Guidelines are important. They help establish safety and standards of care.

But guidelines are not the same thing as the entirety of current scientific evidence.

And when the evidence advances, our thinking needs to advance with it.

A New Study Raises an Important Question

A 2026 paper published in Gynecological Endocrinology examined estradiol blood levels during menopausal hormone therapy and compared them with findings from major studies evaluating menopausal symptoms, bone health, and cardiovascular health.

One of the most interesting findings was that meaningful skeletal and cardiovascular benefits in the studies reviewed were associated with estradiol levels around 60 pg/mL.

That does not mean every woman needs an estradiol level of exactly 60.

She doesn't.

And I would never treat a laboratory value without treating the woman attached to it.

But it does reinforce an important point:

There may be a difference between having enough estrogen to stop a hot flash and having enough estrogen to provide meaningful physiologic support to the bones and cardiovascular system.

That distinction matters.

Symptom Control Is Not the Same as Optimization

Imagine a woman starts an estradiol patch.

Her hot flashes disappear.

She sleeps better.

She feels good.

That is important.

But what if she also has osteopenia, osteoporosis, early menopause, rapid bone loss, or a strong family history of fracture?

Now the question changes.

It is no longer just:

"Do you feel better?"

It becomes:

"Are we providing enough estrogen exposure to support the outcome we are actually trying to achieve?"

If bone protection is one of our goals, I want to know whether the patient is absorbing the medication and whether the dose is producing a reasonable physiologic response.

Telling women that hormone levels "don't matter" shuts down that discussion too early.

Bone Protection Deserves More Than Guesswork

Estrogen plays a major role in maintaining bone.

When estrogen drops during menopause, bone resorption accelerates. For some women, that loss is substantial.

Hormone therapy can reduce bone loss and fracture risk.

The new 2026 analysis adds to the argument that dose and resulting estradiol exposure may matter when bone protection is the goal.

Again, I am not suggesting that we blindly increase estrogen until every woman reaches a particular number.

A laboratory value is one piece of the puzzle.

So are bone density, bone quality, fracture risk, body composition, nutrition, exercise, thyroid health, family history, medications, cardiovascular risk, breast health, uterine health, and personal goals.

That is personalized medicine.

Not Every Woman Absorbs Hormones the Same Way

Put ten women on the same estradiol patch and you will not necessarily get ten identical estradiol levels.

Absorption varies.

Body composition varies.

Metabolism varies.

Genetics vary.

Medications vary.

Gut function varies.

Individual tissue response varies.

So simply writing a prescription and assuming the dose on the box tells us exactly what is happening inside the body does not make sense to me.

If I am prescribing something for a therapeutic purpose, I want reasonable evidence that it is being absorbed and accomplishing what we intended.

What Goes In Matters. What Comes Out Matters Too.

Hormone management should not stop with the prescription.

Estrogen has to be metabolized and eliminated.

The liver plays a major role. So does the gastrointestinal tract and gut microbiome. Nutrient status and multiple enzymatic pathways also influence how hormones are processed.

This does not mean every woman needs extensive hormone-metabolite testing.

It means that when clinically appropriate, I want to understand both sides of the equation:

What are we putting into the body?

Is the patient absorbing it?

Is it producing the effect we want?

And:

Is the body appropriately metabolizing and eliminating what it no longer needs?

Testing should answer a clinical question.

Giving hormones without reassessing the patient is not individualized care.

Neither is ordering endless testing without knowing what to do with the results.

And What About the Heart?

The cardiovascular conversation around menopause has also changed dramatically.

I do not prescribe estrogen as a substitute for cardiovascular prevention.

Cardiovascular risk still depends on blood pressure, insulin resistance, ApoB, Lp(a), triglycerides, glucose metabolism, inflammation, body composition, exercise, sleep, smoking, family history, and actual evidence of vascular disease.

But we also cannot pretend estrogen has no relationship to cardiovascular physiology.

Timing matters.

Starting hormone therapy in a healthy woman close to menopause is very different from beginning treatment decades later in a woman with established disease.

Route matters too.

Transdermal estradiol does not have the same first-pass hepatic effects as oral estrogen and has a more favorable thrombotic profile.

And the 2026 paper raises another important question:

Does the actual level of estradiol exposure influence cardiovascular physiology as well?

The evidence is evolving, and that is exactly why I believe we need to keep reading the literature rather than relying on a simplified rule that says, "Use the lowest dose and don't measure anything."

Evidence Changes. Medicine Has to Change With It.

This may be the most important point.

Women lost years of appropriate treatment because the initial interpretation of hormone research was applied far too broadly.

Over time, we learned that age matters.

Timing matters.

Formulation matters.

Route matters.

Whether a woman has a uterus matters.

The type of progestogen matters.

And the risk-benefit calculation for a healthy 52-year-old woman is very different from the calculation for a woman beginning therapy at 72.

Our understanding changed because the evidence changed and became more sophisticated.

That is how medicine is supposed to work.

So when I hear, "The guidelines don't recommend that," my next question is:

What does the current evidence show?

Guidelines are an important tool.

They should not prevent us from thinking.

And they should not stop an appropriate patient from receiving individualized treatment simply because the science has moved faster than the guideline.

Don't Chase a Number. Don't Ignore It Either.

I do not practice medicine by chasing laboratory values.

But I also do not ignore objective data because someone once said the numbers don't matter.

I look at the whole woman.

How does she feel?

What are her goals?

What is her bone health?

What is her cardiovascular and metabolic health?

What are we giving her?

Is she absorbing it?

Is it enough to accomplish what we intended?

Is she tolerating it?

Is she metabolizing it appropriately?

And are we helping protect the health she will need not just this year, but for the next 20 or 30 years?

The goal should not simply be to get through menopause.

The goal should be to enter the next decades of life with the strongest bones, healthiest cardiovascular system, preserved muscle, healthy sexual function, and best quality of life we can reasonably achieve.

That requires more than following a recipe.

It requires staying current with the evidence.

It requires individualized care.

And sometimes it requires being willing to move beyond an old guideline when the science has already moved forward.

Reference

Piette PCM, Simon JA. Optimizing estradiol serum levels for optimal skeletal and cardiovascular health during transdermal menopausal hormone therapy. Gynecological Endocrinology. Published online July 8, 2026. doi:10.1080/09513590.2026.2694742.

Medical Note: This article is for educational purposes and does not replace individualized medical care.