What Is HRT? A Complete Guide to Hormone Replacement Therapy

Hormone replacement therapy (HRT) is a medical treatment that replaces hormones — primarily oestrogen and progesterone — that the body stops producing during menopause. It is one of the most effective treatments for menopausal symptoms in women and is also used to prevent and treat osteoporosis. Available in multiple forms including tablets, patches, gels, and vaginal preparations, HRT is prescribed following a clinical consultation with a qualified healthcare professional.

What Does HRT Do? The Science Behind Hormone Replacement

During menopause, the ovaries gradually reduce and then stop producing oestrogen and progesterone. These hormones play essential roles across many body systems — not just reproductive function. Their decline triggers the wide range of menopausal symptoms many women experience.

HRT works by supplying physiologically active doses of these hormones to:

• Restore normal thermoregulatory function (reducing hot flushes and night sweats)
• Maintain vaginal tissue health and lubrication
• Support mood stability and sleep quality
• Protect bone density (preventing osteoporosis)
• Support cognitive function and energy levels

Types of HRT: A Complete Overview

1. Combined HRT (Oestrogen + Progestogen)

For women who have a uterus, progestogen must be taken alongside oestrogen to protect the womb lining from the risk of endometrial hyperplasia (overgrowth) and cancer that can result from oestrogen alone. Combined HRT comes in two patterns:

• Cyclical combined — oestrogen taken continuously; progestogen added for part of the cycle; causes regular withdrawal bleeds; suitable for perimenopausal women
• Continuous combined — both hormones taken daily without a break; no expected bleeds; suitable for postmenopausal women (12+ months since last period)

2. Oestrogen-Only HRT

Recommended for women who have had a hysterectomy (removal of the uterus) — there is no womb lining to protect, so progestogen is not needed. Oestrogen-only HRT has a more favourable risk profile for breast cancer than combined HRT.

3. Local (Vaginal) Oestrogen

Vaginal oestrogen preparations (pessaries, rings, creams) deliver oestrogen directly to the vaginal tissue. They are used for urogenital symptoms — vaginal dryness, burning, recurrent UTIs — and have minimal systemic absorption. They can be used by women who cannot take systemic HRT and have no known increased breast cancer risk.

4. Testosterone

Low testosterone in women (associated with menopause) can cause reduced libido, fatigue, and low mood. Testosterone supplementation (usually as a gel) is increasingly recognised as an important component of HRT for these symptoms.

HRT Delivery Methods Compared

Transdermal HRT (patches and gels) is increasingly preferred because it avoids the small increased clot risk associated with oral HRT. For a comparison of specific products, see our menopause and HRT treatment guide and HRT key facts.

HRT Side Effects: What to Expect

Most side effects of HRT occur during the adjustment period (first 2–3 months) as hormone levels stabilise:

• Nausea — more common with tablets; transdermal options may be better tolerated
• Breast tenderness — usually temporary; may improve with dose adjustment
• Bloating — common initially; usually settles
• Headaches — some women experience hormonal headaches in the first weeks
• Irregular vaginal bleeding — common in the first 3 months of cyclical or continuous combined HRT; persist or heavy bleeding should be reported
• Leg cramps — more common with oral HRT; patches and gels may help