What is HRT and how does it work?
Hormone replacement therapy replaces the oestrogen (and where appropriate, progesterone and/or testosterone) that declines during perimenopause. By restoring hormones to levels that alleviate symptoms, HRT addresses the root physiological cause of most perimenopause symptoms — rather than treating individual symptoms separately.
HRT is not a single treatment but a category covering many different hormone types, doses, delivery methods, and regimens. Finding the right formulation for an individual is often a process of adjustment rather than a single prescription — most women reach their optimal regimen within 3–6 months of starting.
NICE guidelines (NG23, updated 2024) state that HRT should be offered to women with perimenopause symptoms affecting quality of life, that for most women under 60 the benefits outweigh the risks, and that no woman should be denied a discussion of HRT on the basis of age alone. If you have been refused HRT or a conversation about it, you are entitled to a second opinion.
Types of HRT
Oestrogen — the core component
Oestrogen is the primary active component of HRT and addresses hot flushes, night sweats, vaginal dryness, sleep disruption, brain fog, joint pain and many other symptoms. It is available in several forms:
| Form | How used | Notes |
|---|---|---|
| Patches (transdermal) | Applied to skin, changed twice weekly or weekly | Consistent delivery; avoids first-pass liver metabolism; lowest blood clot risk |
| Gel (transdermal) | Applied daily to inner arm or thigh | Dose flexibility; same liver/clot benefits as patches |
| Spray (transdermal) | Applied daily to inner forearm | Convenient; same profile as gel and patches |
| Tablets (oral) | Taken daily | Passes through liver; slightly higher blood clot risk than transdermal |
| Implants | Inserted under skin by clinician, lasts 6 months | Consistent levels; requires repeat procedure |
Body-identical oestrogen (oestradiol) — identical in molecular structure to the oestrogen the body naturally produces — is the preferred form in current UK prescribing guidance and is available in all transdermal forms. Transdermal oestradiol is the recommended first-line option for most women due to its superior safety profile compared to oral oestrogen.
Progesterone — required if you have a uterus
Women who have not had a hysterectomy must take progesterone alongside oestrogen to protect the uterine lining (endometrium). Oestrogen alone, without progesterone, stimulates endometrial growth and can cause cancer of the uterus over time — progesterone prevents this.
Micronised progesterone (Utrogestan) is the body-identical form of progesterone. Taken orally at night (it has a sedative quality that is beneficial for sleep), it has a significantly better safety profile than older synthetic progestogens (progestins). Critically, micronised progesterone is not associated with the increased breast cancer risk linked to older combined HRT preparations — this distinction is clinically important and often not communicated to women.
Testosterone
Testosterone — present and important in women — also declines during perimenopause. Low testosterone contributes to reduced libido, low energy, motivation and mood. Testosterone replacement therapy for women (typically prescribed as Testogel off-label in the UK, or Androfeme) has good evidence for improving libido and energy in perimenopause. It is less routinely prescribed than oestrogen-progesterone HRT but is available and increasingly discussed.
Is HRT safe? The current evidence
HRT safety has been significantly re-evaluated since the Women's Health Initiative (WHI) trial in 2002 that generated widespread fear about breast cancer and heart disease. Modern understanding recognises that the WHI results applied specifically to the oral conjugated equine oestrogen and synthetic medroxyprogesterone combination used in that study — not to body-identical transdermal HRT used in current practice.
Breast cancer risk
The breast cancer risk associated with HRT is primarily driven by the type of progesterone used, not oestrogen. The key findings:
- Oestrogen-only HRT (for women without a uterus) — no increased breast cancer risk, and may slightly reduce risk
- Oestrogen + micronised progesterone — no statistically significant increased risk for at least 5 years
- Oestrogen + synthetic progestins (older preparations) — small increased risk, approximately equivalent to drinking one glass of wine per day or being overweight
The absolute risk increase for most women is small. For context: obesity and alcohol both carry higher breast cancer risks than body-identical HRT. The decision to take HRT should weigh this against the well-documented benefits.
Blood clots (VTE) risk
Oral oestrogen (tablets) is associated with a small increased risk of venous thromboembolism (blood clots). Transdermal oestrogen (patches, gel, spray) is not associated with any increased VTE risk at standard doses. This is why transdermal oestrogen is the recommended first-line choice for most women in current NICE guidance.
Cardiovascular effects
When started before 60 or within 10 years of menopause (the "window of opportunity"), HRT is associated with reduced cardiovascular risk — not increased. Oestrogen has protective effects on the cardiovascular system including maintaining arterial flexibility, improving lipid profiles, and reducing inflammatory markers. These benefits diminish when HRT is started significantly after menopause.
Bone density
HRT is one of the most effective protections against the accelerated bone density loss that occurs around menopause. It is associated with significant reduction in fracture risk. See our full guide to bone density by age.
Benefits of HRT
The well-documented benefits of HRT include:
- Resolution or significant reduction of hot flushes and night sweats in ~90% of women
- Improved sleep quality and duration
- Reduced anxiety, low mood and mood instability
- Improved energy and reduced perimenopause fatigue
- Protection of bone density — reducing osteoporosis and fracture risk
- Cardiovascular protection when started in the window of opportunity
- Reduced abdominal fat accumulation
- Improved cognitive function and reduced brain fog
- Resolution of vaginal and urinary symptoms
- Reduced risk of type 2 diabetes
How to access HRT in the UK
Via your GP: The first step for most women. NICE guidelines support GPs prescribing HRT for symptomatic perimenopause. If your GP is not knowledgeable about modern HRT or is reluctant to prescribe, you are entitled to request a referral to a menopause specialist or seek a second opinion.
Menopause clinics: NHS menopause clinics are available in many areas for more complex cases. The British Menopause Society website has a directory of accredited menopause specialists.
Private providers: Dedicated menopause clinics (Newson Health, Liz Earle Wellbeing clinics, etc.) and online services (Menopause Care, Balance Menopause) offer consultations and prescriptions privately. Costs vary but the prescriptions are typically for NHS-standard medications.
If your GP refuses to discuss or prescribe HRT without a clear clinical reason, or cites outdated safety concerns, you are entitled to request a second opinion from another GP or a referral to a menopause specialist. NICE guidelines explicitly state that women with perimenopause symptoms affecting quality of life should be offered HRT. Carry the NICE NG23 guideline summary to your appointment if needed.
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