What 'bioidentical' really means in hormone therapy

A definition about structure

Bioidentical means a hormone is chemically identical to one the human body produces. Estradiol, estriol and progesterone can all be made in bioidentical form. Conjugated equine estrogens, from horse urine, and synthetic progestins such as medroxyprogesterone acetate are not bioidentical, because their structures differ from human hormones.

The term says nothing about how the product is made, who makes it, how pure it is or how much reaches your bloodstream. Those questions are answered by regulation and testing, not by the label.

Natural is doing a lot of unearned work

Bioidentical hormones are often described as natural or plant-based. In reality, both FDA-approved and compounded bioidentical hormones are synthesized in laboratories, commonly starting from plant compounds such as diosgenin from yams. Your body cannot convert yam extract into estradiol or progesterone on its own.

Even if a hormone were extracted from a natural source, that would not make it safer. Estradiol has the same effects on the breast, uterus and blood vessels whatever its origin.

Many FDA-approved products are bioidentical

So choosing an FDA-approved product does not mean giving up on bioidentical hormones. It means choosing a bioidentical product that has been tested and is manufactured to consistent standards.

• Estradiol skin patches, gels, sprays and vaginal rings
• Estradiol tablets and vaginal inserts
• Micronized progesterone capsules, FDA-approved for protecting the uterine lining in postmenopausal women taking estrogen
• Prasterone (DHEA) vaginal inserts for painful sex due to menopause

The real issue: FDA-approved or compounded

Compounded bioidentical hormones are mixed by pharmacies, often in custom combinations and doses. FDA states that compounded drugs are not FDA-approved and that it does not verify their safety, effectiveness or quality before marketing. A 2020 report from the National Academies of Sciences, Engineering, and Medicine found insufficient evidence to support the clinical utility of compounded bioidentical hormone therapy and called widespread use a public health concern.

One practical concern is protection of the uterus. If you have a uterus and take systemic estrogen, a progestogen is needed to prevent overgrowth of the lining. That protection depends on reliable absorption, which is well established for FDA-approved micronized progesterone capsules but not for progesterone creams.

When compounding can make sense

The National Academies recommended limiting compounded hormones to people with a documented allergy to an ingredient in an FDA-approved product or a documented need for a dose or form that no approved product offers. The Menopause Society's practice guidance echoes this and says patient preference alone should not determine their use.

In those situations, a compounded preparation from a licensed pharmacy, prescribed with shared decision-making and monitoring, can be appropriate. Your clinician should explain why it is being chosen over an approved product.

Questions to ask about any hormone prescription

Clear answers to these questions tell you far more about the quality of your care than the word bioidentical on a label.

• Is this product FDA-approved or compounded?
• If compounded, why is it needed instead of an approved product?
• How will my dose be adjusted, by symptoms or by lab numbers?
• If I have a uterus, how is my uterine lining being protected?
• What follow-up and monitoring are planned?

What about hormone testing to customize doses?

Some compounding practices set doses based on saliva or blood hormone levels. The Menopause Society advises against saliva testing, noting its accuracy has not been demonstrated, and says optimal hormone levels in postmenopausal women have not been established. Blood levels also fluctuate during the day.

Dosing is better guided by how your symptoms respond, with the lowest effective dose for your goals. Blood tests still have roles, such as confirming menopause in some situations or checking for other conditions.

How HealifyMD approaches this

HealifyMD clinicians prescribe bioidentical estradiol and progesterone, and some products in the plan are compounded. When that is the case, we say so plainly: compounded hormones are not FDA-approved, and your clinician will discuss whether an FDA-approved option would suit you better. Oral micronized progesterone is used when endometrial protection is needed.

HealifyMD's hormone therapy plan for women is $349 for the first month, then $99/month, and estradiol, estriol vaginal cream and progesterone are included in the hormone therapy program. Compounded hormones are not FDA-approved and are not equivalent to branded products. The first month includes the evaluation and baseline labs, and your price is confirmed at the eligibility review.