Oral HRT vs transdermal HRT (tablets vs patches and gels)

Menopausal hormone therapy replaces oestrogen, which falls around the menopause, to relieve symptoms such as hot flushes, night sweats, sleep disturbance, mood change and vaginal dryness. The oestrogen used in modern HRT is commonly estradiol, which is identical in structure to the main oestrogen the ovaries produce, and it can be given by different routes.

Tablets are swallowed and absorbed through the gut and liver. Patches, gels and sprays are applied to the skin, allowing the hormone to pass directly into the bloodstream. The route affects clotting, blood fats, convenience and skin reactions, but not the basic purpose of treatment.

Tablets are taken once daily, are familiar, and may be preferred by those who dislike patches or gels. Because oral oestrogen passes through the liver before reaching the bloodstream, it changes the production of clotting proteins and some other substances. This is the main reason for the small increase in clot risk with oral oestrogen compared with transdermal.

Oral HRT may be less suitable for those with a higher risk of clots, such as people with a personal or family history, higher body mass index, migraine with aura in some cases, or liver or gallbladder disease, where a clinician may prefer transdermal. For the same reason, oral HRT is not usually the first choice when additional risk factors are present.

Patches are changed once or twice weekly, while gels and sprays are applied daily. They deliver steady oestrogen levels and bypass the liver, so they are not associated with the increased clot risk of oral oestrogen at standard doses. They also may suit people with certain medical conditions, malabsorption, or who experience nausea with tablets.

Downsides include skin irritation from patches, patches coming off, the need to let gels dry and avoid skin contact with others, and the preference some people have for tablets. If a womb is present, a progestogen is still needed and can be taken separately or through a combined patch or intrauterine system, as chosen with the clinician.

NICE guideline NG23 on menopause advises that clinicians discuss the benefits and risks of HRT, that treatment is individualised, and that transdermal preparations may be preferred in people at higher risk of venous thromboembolism since they do not appear to raise that risk. It also advises regular review and explains that the absolute risks of breast cancer and cardiovascular disease depend on the type of HRT, duration and individual factors.

The Faculty of Sexual and Reproductive Healthcare, the British Menopause Society and the Royal College of Obstetricians and Gynaecologists offer patient information that supports shared decision-making. Practical preferences, such as skin sensitivity, ease of use and side effects, often decide between routes when no clear medical reason favours one.

• No particular clot risk factors and a preference for tablets: oral HRT is a recognised option to discuss.

• Previous clot, family history, higher body mass index or other risk factors: ask whether transdermal HRT is more suitable.

• Migraine with aura, gallbladder disease or liver problems: discuss route choice with a clinician.

• Skin sensitivity or difficulty with patches: ask about gels or sprays.

• Persistent side effects or symptoms that are not controlled: review rather than stopping abruptly; doses and routes can be adjusted.

• Unexpected bleeding, calf pain and swelling, chest pain or breathlessness: seek medical advice promptly; sudden chest pain or breathlessness needs 999.

HRT is not one product, and "natural" or "body identical" does not mean risk free or different in how it must be prescribed and reviewed. Transdermal does not remove the need for progestogen when a womb is present. And HRT is not only for hot flushes; some people use it for other menopausal symptoms, as guided by a clinician.

Another misconception is that all HRT carries the same risks. Evidence differs by type, dose, route and individual risk factors, which is why assessment matters.