What is HRT
Hormone Replacement Therapy — also referred to as Menopausal Hormone Therapy (MHT) — is a treatment that replaces the hormones that decline during perimenopause and menopause. The primary hormones involved are oestrogen and progesterone. For some women, testosterone is also prescribed.
During perimenopause, oestrogen levels fluctuate erratically before eventually falling. This hormonal instability is responsible for the majority of symptoms associated with the menopause transition — from hot flashes and sleep disruption to cognitive changes, mood dysregulation, and joint pain. HRT addresses the root cause, not just the symptoms.
HRT is not a new treatment. It has been in use since the 1960s. Its reputation has been shaped significantly — and disproportionately — by a single study: the Women's Health Initiative (WHI) trial published in 2002. Understanding what that study actually found, and what it didn't, is important context for any conversation about HRT.
Types of HRT
The type of HRT prescribed depends primarily on whether you have a uterus, and on your symptoms and medical history.
Body-identical vs synthetic: this distinction matters.
Not all HRT formulations are the same. Body-identical hormones (also called bioidentical or regulated bioidentical) are structurally identical to the hormones produced by the human body. They are derived from plant sources, rigorously tested, and licensed for prescription. Synthetic hormones (such as older progestins like norethisterone and medroxyprogesterone acetate) are chemically similar but not identical — and they carry a different risk and side-effect profile.
The WHI study used synthetic progestins. Much of the ongoing debate about HRT risks is rooted in data from synthetic formulations. Body-identical progesterone (micronised progesterone, sold as Utrogestan) has a more favourable profile, particularly with regard to breast cancer risk and cardiovascular health.
On "compounded" bioidentical HRT: This refers to custom-mixed formulations from compounding pharmacies — often marketed as "natural." These are not regulated in the same way as licensed medicines, their dosing cannot be verified with the same rigour, and they are not recommended by the British Menopause Society. If a practitioner recommends these in preference to licensed body-identical HRT, that is worth scrutinising.
Routes of Administration
How HRT is delivered affects how hormones are absorbed, metabolised, and what risks apply. This is not a minor detail.
| Route | Examples | Notes |
|---|---|---|
| Transdermal patch | Evorel, Estradot, Femseven | Applied to skin, changed every 3–4 days. Bypasses the liver — the key advantage for anyone with elevated clot or stroke risk. Generally the preferred route for oestrogen delivery. Lower VTE risk |
| Transdermal gel | Oestrogel, Sandrena | Applied daily to skin. Same liver-bypass advantage as patches. Dose is more flexible and easy to adjust. Some people prefer this to patches for comfort or adhesion reasons. Flexible dosing |
| Transdermal spray | Lenzetto | Sprayed onto the inner forearm. A newer option with similar benefits to gel. Three sprays roughly equivalent to a standard oestrogel dose. |
| Oral (tablet) | Premarin, Elleste, Progynova | Passes through the liver on first pass, which affects how oestrogen is metabolised and can increase clotting factors. Oral oestrogen carries a higher risk of VTE (venous thromboembolism) than transdermal routes. Higher VTE risk vs transdermal |
| Vaginal / local | Vagifem, Ovestin, Gina, Replens | Oestrogen delivered directly to vaginal tissue for GSM (genitourinary syndrome of menopause). Very low systemic absorption. Can be used alongside systemic HRT or independently. Does not require progestogen. Often underprescribed. Minimal systemic absorption |
| IUS (coil) | Mirena | The Mirena IUS contains levonorgestrel and can serve as the progestogen component of combined HRT when used alongside systemic oestrogen. Provides contraception simultaneously. Licensed for HRT use up to 54 years of age or 5 years post-menopause. |
The Medications
The following are commonly prescribed HRT medications available in the UK. This is not an exhaustive list, and what is appropriate for any individual depends on their medical history and symptoms.
Oestrogen
Progestogen
Testosterone
Testosterone is produced in women by the ovaries and adrenal glands. Levels decline progressively from the mid-thirties, and the transition through menopause can accelerate this. It is frequently overlooked in menopause care, partly because it is not licensed for use in women in the UK — though it is widely prescribed off-label, and supported by NICE guidance.
Low testosterone in women is associated with reduced libido, persistent fatigue, difficulty concentrating, and low mood. These symptoms overlap significantly with oestrogen deficiency, which is why testosterone is often not considered until oestrogen levels are stabilised first.
How to raise it with your GP: Testosterone is not routinely offered and many GPs are unfamiliar with prescribing it for women. If you are experiencing persistent low libido, fatigue or cognitive symptoms despite adequate oestrogen, it is reasonable to ask whether a testosterone trial would be appropriate for you, and to request a referral to a menopause specialist if your GP is not confident prescribing it.
The Evidence
In 2002, the Women's Health Initiative (WHI) published results suggesting HRT increased the risk of breast cancer, heart disease, and stroke. Headlines followed. Prescriptions fell sharply. Women stopped their treatment. Many never restarted.
What was not widely reported: the WHI study used oral conjugated equine oestrogen combined with a synthetic progestin (medroxyprogesterone acetate) — in women who were, on average, 63 years old, more than a decade post-menopause. The absolute risk increase for breast cancer was small. The cardiovascular risks were concentrated in older women starting HRT late.
The British Menopause Society and NICE both support the use of HRT for eligible women and have updated guidance to reflect the current evidence base. The 2002 WHI conclusions have been substantially revised, contextualised, and in some cases overturned by subsequent research.