HRT vs BHRT: What Those Terms Actually Mean

Where the confusion starts

A patient will tell me she wants bioidentical hormones, not "the synthetic stuff."

What she usually means is: I want something that works with my body, and I don't want the risks I've heard about.

That's a reasonable goal. The vocabulary just doesn't do what people think it does.

What "bioidentical" actually means

Bioidentical means the hormone molecule is structurally identical to what your ovaries produce. Estradiol is estradiol whether it comes from a compounding pharmacy or a retail pharmacy shelf.

Here's what surprises most people: the standard hormone therapy I prescribe is already bioidentical.

• Estradiol — patches, gels, sprays, tablets, vaginal rings and creams. FDA-approved. Bioidentical.
• Micronized progesterone — an oral capsule. FDA-approved. Bioidentical.

Both are made in a lab, usually starting from plant sterols. "Natural" doesn't mean harvested from a field. Every hormone medication is manufactured.

What's actually different: FDA-approved vs compounded

This is the distinction that matters clinically.

FDA-approved products are tested for potency, purity, and absorption. Every patch delivers what the label says. There's safety data and a package insert.

Compounded products are mixed by a pharmacy for an individual patient. They're legal and sometimes genuinely necessary — an allergy to a filler, a dose that isn't commercially made, a formulation a patient can't otherwise tolerate. But they aren't reviewed by the FDA for consistency, and studies of compounded preparations have found real variation between what's labeled and what's delivered.

The National Academies reviewed this in 2020 and reached the same conclusion most professional societies have: use FDA-approved hormone therapy when an appropriate product exists, and reserve compounding for situations where it doesn't.

That's how I practice. Not because compounding is bad, but because I want to know exactly what dose you're getting when I'm adjusting it.

Pellets

Pellets are compounded testosterone or estradiol inserted under the skin every few months.

My hesitation is practical. Once a pellet is in, the dose is fixed. If it's too high, I can't take it back out and we wait it out. Blood levels with pellets are frequently higher than what's needed, and supraphysiologic testosterone in women is where side effects like hair loss, acne, and voice changes come from.

There are clinicians who use them thoughtfully. I prefer methods I can adjust week to week.

Saliva testing

I don't use it. Saliva hormone levels don't correlate reliably with blood levels or with symptoms, and no major guideline recommends dosing from them. When testing is useful, serum is what I order.

What I actually look at

When we're choosing a regimen, these are the real decisions:

• Route — transdermal estradiol (patch, gel, spray) versus oral. Transdermal skips first-pass liver metabolism and is not associated with the same increase in blood clot risk as oral estrogen. For most women, that's my default.
• Progesterone — required if you still have a uterus, to protect the uterine lining. Micronized progesterone at bedtime, in most cases.
• Dose — the lowest that controls your symptoms, adjusted over time.
• Testosterone — considered separately, most commonly for low sexual desire with distress, at female physiologic dosing.

None of those decisions are made better by the word "bioidentical" on a label.

The bottom line

If a clinic is selling you on "bioidentical" as the reason their hormones are safer, they're selling you a word.

Ask instead: What molecule is it? What route? What dose? Is it FDA-approved, and if not, why is compounding necessary for me specifically?

Those questions get you a better answer than the marketing does.