HRT
5 MINS

Difference between bioidentical hormones and body identical hormones

by Emily Turner

Do you get confused between bioidentical and body identical hormones when trying to plan your treatment to manage your symptoms? It’s not surprising as the two terms are often muddled up and misused! We’ve put together everything you need to know about the critical differences between the two, so you can make a more informed choice.


In summary, the medical community is concerned that compounded bioidentical hormones are not regulated and it is unclear if the way they are prescribed is safe. Read on to find out more….

Hormone replacement therapy (HRT) and body identical hormones

HRT has a difficult history, which means that there is a lot of confusion and misunderstanding surrounding this treatment. It’s true that in the past, oestrogen was derived from horse urine and given in the form of a tablet. This is no longer the case! Read more about the HRT debate.

Today’s HRT uses body identical hormones for transdermal oestrogen  –  given as a patch, gel or even a spray – and for micronised progesterone, given as a capsule. Body identical hormones have the same chemical structures as the hormones produced by your body naturally. They are derived from plants, extracted from yams and soy. Body identical hormones are subject to tests and are regulated (which means we know where it is produced and exactly what it contains). They are prescribed on the NHS by your doctor, or privately, based on your symptoms

Confusingly, these are also known as regulated bioidentical hormones. Don’t worry, all will be clear soon!

Digested: Body identical hormones are natural, tested and regulated. Your doctor can prescribe you many types of body identical HRT and adapt your dose to help you manage changing symptoms.

Compounded bioidentical hormones 

You may have seen compounded bioidentical hormones advertised by clinics online or healthcare professionals not specifically trained in menopause treatment and care, or have the right accreditations. These are hormones made by pharmacies for a woman based on the results of a saliva or blood test. The pharmacies claim to match the hormones exactly to the result of the test, often given as lozenges or as a cream. 

While they are expensive, women are desperate for a solution to their symptoms. They are attracted by the ease of availability and the fact they are personalised makes them seem safer. It is important to understand that there is insufficient evidence to justify the use of blood and/or saliva tests to personalise menopause treatment in this way. With so many unknowns and risks,  the NHS and the British Menopause Society does not recommend compounded bioidentical hormones as it is not clear how safe and effective they are.

One issue is that basing your treatment on one saliva or blood test only gives a brief snapshot of what is happening in your body. Your hormones are fluctuating all the time and the risk is you may be prescribed too much or not enough, which could have consequences for your long-term health. 

More worryingly, compounded bioidentical hormones are not regulated and you cannot be sure what they contain. The dose and ingredients could be different from what you are told and there could even be contaminants. Also, progesterone cream doesn’t absorb well and might not necessarily protect your womb.

Digested: Body identical hormones are not the same as compounded bioidentical hormones. The NHS and the British Menopause Society do not recommend compounded bioidentical hormones as they are not regulated, there is no evidence they work, it’s unclear if they are safe. Instead, they recommend regulated body identical hormones. 

Final word

Regulated body identical HRT is available and prescribed by healthcare professionals. This has been shown to be effective for relieving menopausal symptoms. Unregulated compounded bioidentical HRT is not recommended as there is not the evidence to show their efficacy and safety, and may cause harm. Women can feel reassured that only regulated HRT is prescribed on the NHS.”

Dr Michelle Griffin, Stella’s Chief Medical Officer

Read more about menopause on our blog.