‘Bioidentical hormones’ are manufactured hormones that have the same chemical and molecular structure as the ones produced in the human body. The term can refer to the FDA– and MHRA-regulated and approved HRT that is available in retail pharmacies, or the individually-tailored preparations available in compounding pharmacies or private clinics. Its origins, however, are as a marketing term for the latter, that in recent years have begun offering ‘bioidentical hormone therapy’ to women. These preparations seem particularly attractive as they are purportedly tailored to the individual. They may also appeal because they are marketed as ‘natural’, because women fear taking conventional HRT due to risks, or because their own doctor has refused them HRT. It is important to understand the difference between these compounded bioidentical hormones, and the regulated, or ‘body-identical’ hormones, that are contained in FDA- and MHRA-approved HRT.

The difference between bioidentical and body-identical HRT

Bioidentical HRT refers to HRT with the same chemical and molecular composition as the hormones made in the human body. FDA-approved (US) or MHRA-approved (UK), regulated, bioidentical hormones are often called ‘body-identical hormones’, to distinguish them from compounded bioidentical hormones that are produced in compounding pharmacies and private clinics to individual needs. While body-identical hormones are subject to vigorous safety tests, quality control and an abundance of medical research, compounded bioidentical hormones have no associated standards, are more expensive, can be subject to inconsistent dosing and there is no evidence to suggest they are better than body-identical forms.

Why compounded bioidentical HRT became popular

The WHI study

When the results of the Women’s Health Initiative (WHI) study were published in 2002, many women were frightened off taking HRT due to the perceived elevated risk of cancer, and its use subsequently plummeted. The effect of this lingers in the public consciousness and medical profession, leaving many women and their doctors uncertain or outright negative about HRT use. Private clinics and compounding pharmacies arose to fill the gap, advertising ‘bioidentical HRT’ that was, and still is, widely broadcast on the internet. Some physicians also follow this approach, which  adds to its credibility.

Natural versus pharmaceutical

Compounded bioidentical HRT can seem like the natural – as opposed to pharmaceutical – option; indeed, it is often marketed as such, being ‘plant-derived’. Natural is often perceived as safer, which is not the case: compounded HRT formulations are not subject to quality control and safety standards. It is worth noting here that most body-identical HRT is also plant-derived, and that compounded bioidentical HRT is still subject to laboratory processing methods.

An individually-tailored approach

In a lucrative market, private clinics and compounding pharmacies appealingly advertise compounded bioidentical HRT as individually-tailored, taking blood and saliva tests to determine a woman’s own hormone levels before creating tablets and creams that supposedly match her needs.

Women are often let down by the medical profession

Many doctors remain badly informed about HRT, or misdiagnose or underestimate women’s symptoms, so withholding HRT treatment. Understandably, women turn elsewhere to seek help for menopausal symptoms that are often troublesome and sometimes downright debilitating.

Compounded bioidenticals can seem safer

Individually-tailored compounded bioidentical products typically do not contain the standard HRT health warnings, which can make them seem safer than body-identical HRT, which does. However, this omission is exactly that: it does not imply safety, the warnings have simply not been included. 

The concern with compounded bioidentical preparations

Misleading and expensive claims

The claims made by purveyors of bio-identical preparations are often misleading. The problem with testing an individual woman’s blood or saliva hormone levels is that these can vary significantly from one day to the next. There can even be variations depending on the time of day. Even if such levels could be measured accurately, there is no established standard of what menopausal women’s optimal hormone levels should be. This means that costly tests are being administered to women with meaningless results of no medical value. 

No safety standards

The subsequent drug mixtures are not subject to quality control and are not tested for safety, or to prove that they work by being absorbed effectively. There are no uniform manufacturing standards. They can also contain additives, preservatives and impurities due to contamination with other preparations that compounding pharmacies produce. In general, there is a lack of research to support the safety or effectiveness of individually-tailed hormone preparations, which are often inconsistently dosed.

Sub-optimal and dangerous dosing

Women may be given progesterone creams that are not absorbed optimally by the body, or oral estrogen, or imbalances of estrogen/progesterone. These can lead to an increase in risk of blood clots, strokes and endometrial cancer. Deaths and renal failure have also been reported due to harm from compounding.

Not approved by national regulatory bodies

In addition to not being approved by the FDA and MHRA, bioidentical preparations are not approved by the British Menopause Society or the North American Menopause Society

The benefits of body-identical HRT

Plant-derived and bioidentical

In the past, the estrogen component of HRT was derived from pregnant mare’s urine, and the progesterone component synthetically made. Nowadays, body-identical HRT is bioidentical; the hormones it contains have the same chemical and molecular structure as those made by the human body. Moreover, most of these preparations also fall under the ‘natural’ umbrella – they are plant-based and typically derived from yams.

Safer and cheaper

Current evidence shows that one of the best methods of HRT administration is via micronised progesterone and the application of transdermal estrogen (via gels or patches), which is what body-identical HRT comprises. Unlike oral estrogen, transdermal estrogen is not associated with an increased risk of blood clots and stroke. Similarly, micronised progesterone has less side-effects than older progesterone formulations. These are much cheaper than compounded bioidentical preparations and safer, being subject to rigorous controls and research.

An individualised approach

It is important to realise that body-identical HRT is also individualized – whilst the preparation itself remains the same, the dose is tailored via trial and error based on relief of the patient’s symptoms.

Approved by national regulatory bodies

In addition to being approved by the FDA and MHRA, bioidentical preparations are approved by the British Menopause Society and the North American Menopause Society