Bioidentical HRT

Written by Hormone Health Director Professor Nick Panay for The Menopause Exchange.

Women going through the menopause may wish to explore different options for controlling menopause symptoms such as night sweats, hot flushes and mood swings. In recent years, so-called ‘natural’ or bioidentical hormones have gained popularity as ‘natural’ and safe alternatives to standard HRT to control hormonal imbalances. However, the information on them can be confusing and occasionally misleading.

Bioidentical hormones have been marketed as being gentler on a woman’s body, and some well-known celebrities swear by their effectiveness in relieving their menopausal symptoms. It’s advisable to use conventionally regulated bioidentical HRT (rBHRT) rather than the compounded bioidentical HRT (cBHRT) prescribed by some private clinics.

So what’s the truth about bioidentical hormones and should you try them? Are they a ‘natural’, safe alternative to standard HRT or a potentially risky menopause treatment?

What are bioidentical hormones?

Bioidentical hormones are precise duplicates of hormones made in the human body, such as oestrogen, progesterone and testosterone. All bioidentical hormones are plant-based and aren’t derived from mares’ urine like some older forms of HRT, and they have to be manufactured in a laboratory.

‘Natural’ doesn’t necessarily mean 100% safe

Bioidentical hormones are designed to change the body’s mechanisms in some way to relieve menopausal symptoms, just like standard HRT. Although rBHRT products are made from natural sources, they’re also closely regulated and stringently tested for safety and long-term side effects.

There’s some evidence from recent research that rBHRT preparations are associated with a lower risk of blood clots and breast cancer, particularly during the first five years of use, compared to conventional HRT. But women should still be informed about the possible small increased risk of breast cancer of up to one extra case per 1000 women per year with long-term use of bioidentical hormone therapy, particularly beyond five years. There’s good evidence that oestrogen delivered through the skin is safer for women at an increased risk of blood clots. But it can’t be said that there’s no risk at all with any of these products.

Role of the regulators

Standard synthetic HRT as well as rBHRT are conventionally regulated by the Medicines and Healthcare products Regulatory Agency (MHRA) in the UK. This organisation makes sure that medicines have reached certain standards of safety, quality and effectiveness and that each medicine is guaranteed to be the same strength in each batch.

Pharmaceutical companies are also required to include information about their medicines on safety and possible long-term side effects, which isn’t the case with cBHRT. The HRT prescribed by compounding pharmacies isn’t conventionally regulated and isn’t recommended by the National Institute for Health and Care Excellence (NICE) and the British Menopause Society. Compounding pharmacies (also called special pharmacies) provide bespoke (custom-made) medicines ‘tailor-made’ to an individual patient. This involves combining two or more medicines.

Where to get further advice?

To make sure you’re getting the best form of HRT for you, it’s important that you seek the advice of a qualified healthcare professional who can advise you on the treatments that have been thoroughly researched for safety and effectiveness.

What do NHS menopause clinics prescribe?

NHS menopause clinics usually prescribe conventionally regulated and licensed hormone therapies following NICE and British Menopause Society guidelines. But many are now prescribing plant-based hormones (rBHRT), rather than the mares’ urine or synthetic hormones used in traditional HRT. Compounded implanted oestrogen and testosterone pellets are occasionally used in a few clinics when other types of HRT haven’t helped.

British Menopause Society (BMS) and International Menopause Society (IMS) recommendations

The BMS advice is that using custom compounded bioidentical hormone therapy isn’t recommended; this guidance is available on the BMS website.

The International Menopause Society (IMS) recommendations state the following concerning conventionally regulated bioidentical hormone therapy.

“Natural progesterone and some progestogens have specific beneficial effects that could justify their use besides the expected actions on the endometrium.”

“Progestogens may not be alike in regard to potential adverse metabolic effects or associated breast cancer risk when combined with long-term oestrogen therapy.”


There’s evidence that replicating the hormonal environment in the body by using human oestrogen and natural progesterone can maximise the benefits and minimise the side effects and risks of HRT. It’s time we moved away from the notion, often propagated by epidemiologists and the media, that HRT products have a single class effect. But the conventionally regulated bio-identical products (rBHRT) must not be confused with the bio-identical products from compounding pharmacies (cBHRT).

In order to avoid confusion, it’s been proposed that conventionally regulated HRT products should be referred to as “body” rather than “bio” identical. The published data so far suggests that differential effects can be achieved by using body-identical HRT in comparison to synthetic non body-identical HRT.

Further data from larger studies on major cardiovascular and breast risks are required to confirm these effects. In the meantime, the logical approach for healthcare professionals is to continue to prescribe individualised HRT regimens from the whole formulary according to the evidence base, BMS and IMS recommendations, and taking into account each woman’s benefit:risk profile.

About the author

Professor Nick Panay is a Consultant Gynaecologist at Queen Charlotte’s & Chelsea and Chelsea & Westminster Hospitals and Professor of Practice, Imperial College London. He’s also the Director of Hormone Health.

Source: The Menopause Exchange

This article is written for The Menopause Exchange newsletter which contains articles written by healthcare professionals (such as gynaecologists, GPs, consultants, pharmacists, specialist menopause nurses and dietitians), complementary therapists and major medical charities.

For more information and to subscribe visit the The Menopause Exchange website

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