Are bioidentical hormones safer than standard HRT?

A regulated prescription is licensed HRT, so it carries the benefits and risks of that medicine. For compounded mixes, the FDA has no finding of a safety advantage over approved hormone therapy.

Is compounded HRT the same as body-identical HRT?

Body-identical on an NHS prescription is a regulated medicine a clinician can issue. Compounding means a pharmacy mixes a strength or a combination for one person, outside that licence.

What does FDA approved mean for bioidentical hormones?

It means the FDA has reviewed a specific medicine, such as certain estradiol and micronized progesterone products. A pharmacy compound made to order sits outside that review.

Can a saliva test set the dose?

The Menopause Society says levels in saliva, blood or urine move too much for one result to set a compounded dose.

Hormone therapy

Bioidentical hormone replacement therapy

Bioidentical only describes a hormone molecule that matches one the body makes. Regulated body-identical oestradiol and micronised progesterone are licensed HRT on the NHS, with the benefits and risks of licensed HRT, and custom-compounded mixes have not been shown to be safer.

By Ines Kovac. Published 17 October 2026. 7 minute read.

Summarize with:

A blonde woman in a white patterned blouse sits across a white desk from a doctor in a white coat, who is speaking with his hands open. A blue laptop, a grey desk lamp and a small plant are on the desk.

What is bioidentical hormone replacement therapy?

Bioidentical hormones are chemically the same as hormones the ovaries make, in particular oestrogen and progesterone. The British Menopause Society calls the regulated version a precise duplicate of a human hormone, authorised by a regulator such as the MHRA in the UK (British Menopause Society: bioidentical HRT).

Clinics and shops apply the same word to those authorised prescriptions and to mixes a compounding pharmacy makes up. NICE surveillance text separates the two: regulated hormones that are chemically identical to human hormones, and unregulated mixes from compounding pharmacies (NICE NG23 surveillance appendix).

NHS pages use body-identical, sometimes written as two words, for the regulated medicine. The NHS says these hormones have been regulated, tested and thoroughly researched, so a prescriber can use them to treat menopause (NHS: herbal remedies and complementary medicines).

Body-identical HRT on an NHS prescription

On a UK prescription this is usually oestradiol as a patch, a gel or a tablet, with micronised progesterone when a progestogen is needed. The British Menopause Society treats those MHRA-authorised products as regulated body-identical HRT.

NICE calls licensed HRT the most effective treatment for vasomotor symptoms, the hot flushes and night sweats (NICE discussion aid, 2024). The evidence review treats regulated bioidentical hormones as part of that standard evidence, and states that compounded bioidentical hormones are excluded (NICE evidence review).

See HRT risks in plain numbers per 1,000 women for breast cancer, clots and stroke on licensed therapy.

FDA-approved bioidentical hormones

FDA-approved bioidentical hormone replacement therapy means a medicine the FDA has licensed. The agency has approved drugs that contain hormones identical to those women make in their reproductive years (FDA: menopause). Many products marketed as bioidentical are compounded, and those compounded products are not the approved drugs.

ACOG names micronized progesterone, estradiol and DHEA among the FDA-approved bioidentical hormones. It keeps them apart from compounded preparations, which are not FDA-regulated (ACOG clinical consensus, 2023). American sources write estradiol and micronized progesterone for the molecules UK pages call oestradiol and micronised progesterone.

ACOG says compounded bioidentical menopausal hormone therapy should not be prescribed routinely when an FDA-approved formulation exists.

What compounded products are

A compounding pharmacy prepares these at a custom strength, by a custom route, or as a combination of hormones. The mix does not go through MHRA or FDA licensing. The British Menopause Society does not recommend the prescribing of compounded bioidentical HRT (BMS consensus statement, April 2026). The consensus page says prescribing of these products is not recommended by national or international guidance.

NICE tells clinicians to explain that the efficacy and safety of unregulated hormone preparations are unknown (NICE NG23 recommendations). The NHS does not recommend bioidentical or "natural" hormones sold outside regulated prescribing, including from health shops. They are not regulated, it is unclear whether they are safe, and it is not known how much they help.

Benefits of bioidentical hormone replacement therapy

The benefits of bioidentical hormone replacement therapy depend on whether the medicine is regulated. A regulated prescription brings the vasomotor relief NICE describes for licensed HRT. A compounded mix has not been shown to relieve symptoms beyond what licensed HRT already does.

The Menopause Society 2022 position statement says there is insufficient evidence to support overall clinical use of compounded bioidentical hormone therapy for menopause symptoms (The Menopause Society, 2022). The FDA does not have evidence that compounded bioidentical hormones are safe and effective, or safer or more effective than FDA-approved hormone therapy for menopause.

An approved medicine that contains a hormone identical to one the body makes keeps the risk profile of that approved medicine. Those licensed-therapy numbers are the ones in the risks guide linked above.

Pros and cons of bioidentical hormone replacement therapy

The pros and cons of bioidentical hormone replacement therapy depend on which product the prescription names. A regulated one is an authorised medicine, with constituents fixed by the licence, issued through a GP or a menopause clinic.

Patient preference alone should not be used to justify compounded bioidentical hormone therapy. That is the Menopause Society limit, and it holds even when a custom mix feels more personal.

A narrow opening remains for the prescriber. The same statement says prescribers should only consider compounded therapy if a woman cannot tolerate a government-approved therapy, or needs a dose or a form that is not commercially available, and should document the reason.

Saliva tests and personalised dosing

Clinics often offer a saliva test, or a blood or urine panel, as a way to choose a personalised dose. The Menopause Society considers saliva, serum and urine hormone tests unreliable for dosing compounded therapy, because absorption varies and levels move from day to day.

If symptoms continue on a licensed prescription, ask the prescriber to review the dose, the route or the preparation.

What to ask your clinician

Is this prescription a licensed body-identical product, or a compounded mix, and what is the reason for that choice?
If an approved product is a poor fit, is that because it cannot be tolerated, or because the dose or the form is not sold?
If symptoms continue, which part of this licensed prescription would you review first: dose, route or preparation?

Take the full list of symptoms into the room. The menopause symptom checklist for your GP is built for that. Weight often comes up in the same visit. The trials on whether HRT causes weight gain answer that worry on their own. If periods have not stopped, the perimenopause guides cover how treatment is chosen at that stage. The rest of what we have written on prescriptions is on the hormone therapy (HRT) topic hub.

My take

I would ask one question before any other. Is this a licensed body-identical medicine, or a compounded mix? If the answer is regulated oestradiol, with micronised progesterone where a progestogen is needed, I would treat that prescription as licensed HRT and use the risk numbers for licensed therapy. I would not choose a compounded mix sold as safer or more natural.

Sources

Comments

No comments yet. Questions and your own experience are welcome.

Thank you. Your comment will appear once it has been reviewed.