Wellness
June 7, 2025

Bioidentical Hormone Therapy: FDA-Approved vs Compounded

Bioidentical hormone therapy uses hormones with the same chemical structure as the ones your body makes. There are two kinds. FDA-approved bioidentical products are tested and regulated. Custom-compounded ones, including compounded hormone pellets, are not, and the FDA says it has no evidence that they are safer or more effective than approved hormone therapy.

This guide explains the difference, what the main medical bodies say, and what to ask before starting.

What is bioidentical hormone therapy?

The Endocrine Society defines bioidentical hormones as substances with exactly the same chemical and molecular structure as hormones produced in the human body. They are made in a laboratory from plant sources. Estrogen, progesterone and testosterone are the ones most often used.

The Menopause Society notes that “bioidentical hormone therapy” began as a marketing term for custom-compounded hormones. Cleveland Clinic adds that although these products are often advertised as natural, they are altered in a laboratory and are no longer natural once processed.

Two kinds of bioidentical hormone therapy

FDA-approved products

Many approved hormone therapy products are bioidentical. The Endocrine Society lists oral estradiol, estradiol patches, gels and sprays, vaginal estradiol creams, tablets and rings, and micronized progesterone. These are made under strict manufacturing oversight and dispensed by ordinary pharmacies, in a range of doses.

Custom-compounded products

These are mixed by a compounding pharmacy to a prescription. They come as pills, creams, gels, vaginal inserts or implanted pellets, and may combine several hormones.

The individual ingredients may be approved, but the finished product is not. The FDA states that compounded “bioidentical hormones” are not FDA-approved, and that it “does not have evidence that compounded ‘bioidentical hormones’ are safe and effective, or safer or more effective than FDA-approved hormone therapy.”

What medical bodies say about compounded hormones

FDA. It recommends that women use hormone therapies that are FDA-approved.
ACOG. “There is no scientific evidence that compounded hormones are safer or more effective than standard hormone therapy.” ACOG recommends FDA-approved hormone therapy over compounded hormone therapy.
Endocrine Society. “There is no evidence-based medical need for the use of compounded hormone therapy when an FDA-approved preparation is available.”
The Menopause Society. Custom-compounded hormones “are not safer or more effective than approved bioidentical hormones.”

In 2020 the National Academies of Sciences, Engineering, and Medicine published a review of compounded bioidentical hormone therapy, carried out at the FDA’s request.

Why compounding raises concerns

Dose and purity. ACOG says compounded hormones “vary in strength and purity”, so “you can take too little or too much of a hormone without knowing it.” The Menopause Society explains why that matters: too little progesterone leaves the uterus unprotected against endometrial cancer, and too much estrogen can overstimulate the uterine lining and breast tissue.

Side-effect reporting. Cleveland Clinic points out that compounding pharmacies do not have to report side effects to the FDA or supply the patient leaflet that comes with approved medicines. This can make compounded hormones look safer than they are.

Untested combinations. Some compounded blends include hormones that are not in any FDA-approved product. The FDA notes that there are no approved drugs containing estriol, and that it has no evidence estriol is a “safer form of estrogen”.

Bioidentical hormone pellets

Pellets are small implants placed under the skin that release hormone over time.

ACOG states that there are “safety concerns about a kind of compounded drug known as pellet therapy.” The Endocrine Society cites a study that found blood hormone levels well above the expected range in women using compounded pellets.

If pellets are offered to you, ask whether the product is FDA-approved for your sex and condition, and how the dose would be adjusted.

Saliva and blood testing to “customize” doses

Compounded therapy is often sold with hormone testing to tailor the dose. The Endocrine Society says claims that saliva tests can do this “are not supported by scientific data.” Cleveland Clinic notes that the FDA recommends against using hormone levels to guide dosing in women, because normal levels fluctuate from day to day.

The Menopause Society describes finding the right dose and regimen as a period of trial and error, with adjustments over time.

Are bioidentical hormones safer?

Not by virtue of being bioidentical. The Endocrine Society says that if dose and purity were equal, all estrogen and progesterone therapy “would be expected to carry essentially the same risks and benefits.” Cleveland Clinic lists the same risks as for other hormone therapy: blood clots, stroke and gallbladder disease, with heart disease and breast cancer risk possibly higher with age or long use.

Our posts Is HRT safe? and What is HRT? cover those risks and who should avoid hormone therapy.

Questions to ask before bioidentical hormone therapy

Is the product you are recommending FDA-approved, or is it compounded?
If it is compounded, why not an approved bioidentical product?
If I have a uterus, how will the lining be protected?
How will you decide and adjust my dose?
What are the risks for someone with my medical history?
How often will we review whether I should continue?

Frequently asked questions

Is bioidentical hormone therapy FDA-approved?

Some of it is. Approved products such as estradiol patches and micronized progesterone are bioidentical. Compounded products are not approved.

Are bioidentical hormones natural?

They start from plant sources but are processed in a laboratory. “Natural” does not mean safer, as the FDA reminds consumers.

How long does bioidentical hormone therapy take to work?

Cleveland Clinic says some people feel mild relief within a few weeks, and that it usually takes about three months to feel the full effect of any hormone therapy.