Menopause is a significant biological shift, and the hormonal changes it brings can impact everything from sleep and mood to memory, sex drive, and overall wellbeing. Hormone replacement therapy (HRT) is one of the most effective ways to manage these symptoms. But with terms like "bioidentical" and "body identical" often used interchangeably, iit can be difficult to know what’s safe, effective, and evidence-based.
In this article, we break down the key differences between bioidentical and body identical HRT, so you can make an informed decision about what’s right for your health.
What is bioidentical HRT?
Bioidentical hormone replacement therapy refers to compounded hormone treatments made to closely mimic the hormones naturally produced by your body, such as oestrogen, progesterone, and testosterone. These are often derived from plant sources, like yams or soy, and compounded into custom doses by specialist pharmaceutical companies.
These treatments are frequently marketed as ‘natural’ and ‘personalised’, and while the idea can sound appealing, there’s a significant caveat. In the UK, these compounded preparations are not regulated by the Medicines and Healthcare products Regulatory Agency (MHRA). This means they don’t undergo the same rigorous safety checks or quality controls as licensed medications. This lack of oversight raises concerns over variability in dosing and purity, unpredictable side effects, and questions about long-term safety and as such, these forms of HRT are not recommended by The British Menopause Society [1].
What is body identical HRT?
Body identical HRT is also made from plant-derived sources and designed to replicate the body’s own hormones. However, the key difference is that these hormones are produced by licensed pharmaceutical manufacturers and are strictly regulated.
In other words, body identical HRT is a form of regulated bioidentical HRT.
These treatments are approved by the MHRA and recommended by NICE (the National Institute for Health and Care Excellence) [2]. This form of HRT is widely supported by medical professionals, including the British Menopause Society, who advise the use of regulated body identical hormones in place of unregulated bioidentical ones.
You may have heard of products like Utrogestan (micronised progesterone) or Estradot patches. These are examples of body identical HRT available on the NHS and through private clinics.
HRT vs bioidentical vs body Identical: Understanding the labels
The terminology can be confusing. Traditional HRT, which became available to women in the UK in 1965 [3], included hormones derived from animal sources, such as conjugated equine oestrogens (extracted from horse urine). These are considered ‘non-body identical’ because they don’t chemically match human hormones.
Today, while non-body identical preparations are still available, most healthcare providers prefer regulated body identical HRT. However, unregulated bioidentical hormone replacement therapy is still promoted by some private clinics, often at a premium cost and without robust evidence of improved outcomes.
Side effects: bioidentical HRT
As bioidentical hormone replacement therapy is not standardised, side effects can be difficult to identify and can vary widely. Women may experience:
- Mood swings, fatigue, or headaches (due to hormone level fluctuations)
- Skin irritation from creams or gels
- Irregular bleeding or spotting
- Symptoms of overdosing, such as breast tenderness, bloating, or acne
One study involving over 500 women reported higher rates of adverse effects, including weight gain, hair pattern changes, acne, mood swings, breast tenderness and abnormal cholesterol levels, among those taking compounded bioidentical HRT pellets compared to women using regulated HRT products [4].
Side effects: body identical HRT
As body identical HRT has gone through rigorous testing, its side effects are well-documented. Many women have few, if any, side effects. For those who do have side effects, they are typically mild and tend to settle within the first few months. Side effects may include:
- Spotting or bleeding between periods
- Breast tenderness
- Headaches
- Nausea
- Diarrhoea
- Mood changes, including low mood or depression
- Vaginal spotting
- Mild bloating or changes in weight
- Acne
- Mild rash or itchy skin
- Leg cramps
- Hair loss [5]
As these treatments are tightly controlled, doses can be adjusted easily if you are experiencing side effects that you feel are unmanageable or are affecting your quality of life.
Risks: bioidentical HRT
The biggest concern with bioidentical hormone replacement therapy is uncertainty. Without regulation, there's no guarantee about what's actually in the prescription, or how your body will respond to it.
Some compounded versions use substances like DHEA or pregnenolone, which may not be safe or effective for menopausal women. Progesterone delivered as a cream, for example, is poorly absorbed and may not protect the womb lining adequately [6].
There’s also concern about increased risks of blood clots and endometrial cancer due to uneven oestrogen dosing [6]. Simply put, the risks are hard to quantify because the studies haven’t been done.
Risks: body identical HRT
Like all medications, body identical HRT does carry some risks. However, these are small, measurable, and often outweighed by the benefits. The known risks of body identical HRT include:
- Breast cancer: A small increased risk is associated with combined oestrogen and progesterone use (around five extra cases per 1,000 women after five years) [7].
- Blood clots and stroke: These risks are mainly linked to oral HRT tablets. Transdermal options like patches or gels do not increase clot risk [7].
- Ovarian cancer: Both combined and oestrogen-only HRT slightly increase the risk of ovarian cancer [8].
These risks decrease once HRT is stopped, and they are carefully considered by your doctor when creating a treatment plan. Oestrogen-only HRT can increase the risk of womb cancer, with the risk increasing the longer it is used and remaining for some time even once HRT is stopped. This is why it’s typically only prescribed to women who have had a hysterectomy [8].
Is bioidentical HRT available on the NHS?
No. Compounded bioidentical HRT is not offered on the NHS because it is unlicensed and unregulated. You may encounter it in private clinics, but it’s important to understand the limitations and risks.
Is body identical HRT available on the NHS?
Yes, and widely so. Body identical HRT is often the first-line recommendation in NHS menopause treatment plans and is available in a variety of formats including tablets, creams, gels, sprays, pessaries and vaginal rings. Options include:
- Oestrogen tablets, patches, gel and spray
- Tablets: Elleste Solo, Progynova and Zumenon
- Patches: Estraderm, Estradot, Evorel, Femseven and Progynova
- Gel: Oestrogel and Sandrena
- Spray: Lenzetto
- Vaginal oestrogen
- Vaginal tablets: Gina, Vagifem, Vagirux
- Vaginal ring: Estring
- Vaginal pessaries: Imvaggis
- Vaginal gel: Blissel
- Vaginal cream: Ovestin
- Micronised progesterone
- Utrogestan
- Gepretix
- Continuous combined HRT
- Tablets and capsules: Bijuve, Elleste Duet Conti, Femoston-conti, Indivina, Kliofem and Kliovance
- Patches: Evorel Conto and FemSeven Conti
- Sequential combined HRT
- Tablets: Elleste Duet, Femoston, Novofem, Tridesta and Trisequens
- Patches: Evorel Sequi and FemSeven Sequi
Testosterone is not currently licensed by the NHS to treat menopause symptoms, but it is available off-label from some private menopause specialists.
The bottom line
Menopause isn’t about decline; it’s a shift, and with the right support, you can thrive throughout the transition. Choosing the right hormone therapy is a personal decision, but it should always be an informed one.
While bioidentical HRT might sound appealing, its lack of regulation makes it a riskier option. Body identical HRT, on the other hand, offers the benefits of natural hormone structure, combined with the safety and reassurance of robust medical oversight.
¹Bioidentical HRT (March 2024) https://thebms.org.uk/wp-content/uploads/2024/04/01-BMS-ConsensusStatement-Bioidentical-HRT-MARCH2024-A.pdf
²Recommendations | Menopause: identification and management | Guidance | NICE (November 2024) https://www.nice.org.uk/guidance/ng23/chapter/recommendations
³HRT: The history | Women's Health Concern (November 2022) https://www.womens-health-concern.org/wp-content/uploads/2022/11/10-WHC-FACTSHEET-HRT-The-history-NOV22-A.pdf
⁴Safety assessment of compounded non-FDA-approved hormonal therapy versus FDA-approved hormonal therapy in treating postmenopausal women - PubMed (May 2021) https://pubmed.ncbi.nlm.nih.gov/33973545/
⁵Side effects of hormone replacement therapy (HRT) - NHS (January 2023) https://www.nhs.uk/medicines/hormone-replacement-therapy-hrt/side-effects-of-hormone-replacement-therapy-hrt/
⁶The dangers of compounded bioidentical hormone replacement therapy - PMC (September 2019) https://pmc.ncbi.nlm.nih.gov/articles/PMC6808563/
⁷Benefits and risks of hormone replacement therapy (HRT) - NHS (February 2023) https://www.nhs.uk/medicines/hormone-replacement-therapy-hrt/benefits-and-risks-of-hormone-replacement-therapy-hrt/
⁸Does hormone replacement therapy (HRT) increase the risk of cancer? (March 2023) https://www.cancerresearchuk.org/about-cancer/causes-of-cancer/hormones-and-cancer/does-hormone-replacement-therapy-increase-cancer-risk
