Compounded bioidentical hormones: why professional bodies urge caution

In compounding, a pharmacy mixes active ingredients into a cream, capsule, lozenge or pellet according to a prescriber's order. In UK law this can be lawful when a patient has clinical need that a licensed product does not meet, but it is not intended as a general alternative where licensed options exist. Compounded products are not assessed by the MHRA for quality and effectiveness in the same way as licensed medicines.

• Dose consistency: the amount of hormone absorbed from creams and some pellets varies and cannot be reliably predicted.

• Womb protection: oestrogen without adequate progestogen can thicken the lining and raise the risk of womb cancer; creams do not reliably deliver enough progesterone for protection.

• Lack of safety data: there are no large trials of custom formulations.

• Misleading testing: saliva and some blood tests are used to justify treatment, but hormone levels fluctuate and do not correlate with symptoms in the way implied.

• Pellet implants can deliver high and prolonged hormone levels that are hard to reverse.

Marketing sometimes claims that testing shows a "hormone imbalance" requiring precise correction. NICE guidance says that in women over 45 with typical symptoms, menopause can be diagnosed without blood tests, and it does not recommend routine testing to dose HRT. Hormone levels vary through the day and cycle, and a single result rarely changes management.

Licensed body-identical hormones have the same molecular structure as those the body makes, so being compounded adds no biological advantage. "Natural" does not mean safe: some plant-derived substances carry risks, and unregulated products have caused harm in other settings. A regulated product with known contents and a clear evidence base is a more reliable choice.

Do not stop abruptly without advice if you have been using them for some time. Tell your GP or a menopause specialist what you are using, including doses, so that they can assess womb safety, review symptoms and discuss regulated alternatives. If you are taking oestrogen without a licensed progestogen and you have a womb, ask promptly about protection, and report any unusual bleeding.

Ask whether the products are licensed, who prescribes, how the womb will be protected, what follow-up is arranged and what evidence supports the approach. Be cautious about clinics that rely on saliva testing, promise rapid transformation or discourage you from speaking to your GP. Check the prescriber's registration with the GMC.

If you have experienced problems with a compounded product, such as unexpected bleeding, severe headaches, mood changes or signs of excess hormone like acne and hair growth, tell your GP and report it through the MHRA Yellow Card scheme. If you were charged for a programme that you now feel was misleading, keep records and consider contacting Citizens Advice or the relevant regulator. The General Medical Council deals with concerns about doctors, and the Care Quality Commission about registered services in England.