Compounded bioidentical hormones: the evidence does not back the marketing

Custom-compounded "bioidentical" hormones, marketed as natural and individually tailored, have not been shown to be safer or more effective than the licensed menopausal hormone therapies they are pitched to replace [s1][s2]. The most thorough independent review, from the US National Academies of Sciences, Engineering, and Medicine, found the evidence insufficient and recommended restricting their use [s1].

This is not a niche corner of the market. The National Academies committee estimated that compounded bioidentical hormone therapy — cBHT — accounts for 26 to 33 million prescriptions a year in the United States, at a cost of upwards of $2 billion annually [s1]. A large industry has grown on a claim the evidence does not support.

What "bioidentical" does and does not mean

The word is doing marketing work. "Bioidentical" simply means the hormone molecule is chemically identical to one the body makes — estradiol, progesterone, estriol, testosterone. That property is not unique to compounded products: several FDA-approved menopausal hormone therapies already use bioidentical estradiol and progesterone, tested for safety, dose and consistency. Compounding pharmacies use the term to imply their preparations are natural and therefore safer and more effective than approved medications, but the evidence to support those marketing claims is lacking, the American College of Obstetricians and Gynecologists states [s2].

The real distinction is not the molecule but the process. A compounded product is mixed by a pharmacy for an individual and has not been through the FDA review that approved products undergo, so its purity, potency and dose-to-dose consistency are not verified the same way.

Where the concern actually sits

The National Academies review located the problem in oversight. Federal and state controls over the formulation, marketing, dispensing, surveillance and adverse-event reporting of compounded preparations are insufficient to identify and communicate the risks patients take on when using cBHT [s1]. Its central conclusion followed directly: the committee's first recommendation is to restrict the use of compounded bioidentical hormone therapy [s1].

A common selling point deserves particular scrutiny — the practice of ordering saliva or blood hormone tests and then "customising" a hormone dose to the result. There is no validated basis for titrating menopausal hormones to those measurements, and the personalised precision the testing implies is not real.

What the professional bodies advise

The guidance from clinical societies is consistent and blunt. ACOG's clinical consensus is that compounded bioidentical menopausal hormone therapy should not be prescribed routinely when FDA-approved formulations exist, and that clinicians should recommend the approved therapies for managing menopausal symptoms over compounded ones [s2]. If a patient still requests a compounded product, ACOG says the clinician should explain that it lacks FDA approval and set out its potential risks, including those specific to compounding [s2]. ACOG also notes what would actually resolve the question: high-quality, placebo-controlled randomised trials with long-term follow-up comparing custom-compounded products against approved hormone therapy — trials that have not been done [s2].

The Endocrine Society reached the same place in plainer words, finding no rationale for routine prescribing of unregulated, untested and potentially harmful custom-compounded bioidentical hormone therapies [s3].

The honest reading

Menopausal hormone therapy itself is effective for hot flushes and the genitourinary symptoms of menopause, and modern approved formulations already include the bioidentical hormones the compounding market advertises. The case against cBHT is therefore not a case against hormones. It is that paying more for an unlicensed, unverified version — often justified by hormone tests that cannot guide dosing — buys added uncertainty rather than added safety [s1][s2][s3]. Where a genuine need exists, such as an allergy to an ingredient in every approved product or a dose or form that is not manufactured, compounding has a legitimate, narrow role [s1].

This article describes what independent reviews and clinical guidelines report and is not medical advice. Any decision about menopausal hormone therapy belongs with a clinician who knows the individual's history and risks.

Sources

• The Clinical Utility of Compounded Bioidentical Hormone Therapy: A Review of Safety, Effectiveness, and Use — National Academies of Sciences, Engineering, and Medicine, 2020-09-22
• Compounded Bioidentical Menopausal Hormone Therapy: ACOG Clinical Consensus No. 6 — Obstetrics & Gynecology (ACOG), 2023-09-01
• Compounded Bioidentical Hormones in Endocrinology Practice: An Endocrine Society Scientific Statement — The Journal of Clinical Endocrinology & Metabolism, 2016-07-01