Hormone Journal

Hormone replacement therapy

Also known as: HRT, menopausal hormone therapy, MHT

Medically reviewed by Hormone Journal Editorial Team · Last reviewed 2026-05-22

Hormone replacement therapy (HRT) is a medical treatment that replaces estrogen — and often progestogen — lost at menopause, used by roughly 1 in 8 Canadian women in their 50s.

What it is

Hormone replacement therapy (HRT) is a medical treatment that replaces estrogen — and often progestogen — lost at menopause, used by roughly 1 in 8 Canadian women in their 50s to relieve vasomotor symptoms and protect bone density. Also called menopausal hormone therapy (MHT), HRT is the most effective available treatment for moderate-to-severe hot flashes, night sweats, and genitourinary symptoms of menopause. Current evidence from the Menopause Society, ACOG, and SOGC supports initiating HRT before age 60 or within 10 years of the final menstrual period — a window often called the "timing hypothesis" — when benefits are most likely to outweigh risks for healthy, symptomatic individuals.

HRT is not a single drug. It encompasses a range of estrogen formulations, delivery routes, and progestogen combinations, each carrying a distinct benefit-risk profile.

Causes and mechanism

Menopause — defined as 12 consecutive months without a menstrual period — results in a sharp decline in ovarian estradiol and progesterone production. Falling estrogen destabilizes the hypothalamic thermoregulatory centre, producing vasomotor symptoms, and accelerates bone resorption, raising fracture risk. HRT works by restoring circulating estrogen to low-normal premenopausal levels, dampening vasomotor instability and slowing bone turnover. In people with an intact uterus, unopposed estrogen stimulates endometrial proliferation and raises the risk of endometrial cancer; adding a progestogen (synthetic progestin or micronized progesterone) counteracts this effect.

Symptoms and diagnosis

HRT is indicated for, but not limited to, the following menopausal symptoms:

  • Vasomotor symptoms — hot flashes, flushing, night sweats (affect up to 80% of menopausal individuals)
  • Genitourinary syndrome of menopause (GSM) — vaginal dryness, dyspareunia, recurrent urinary tract infections
  • Sleep disruption secondary to night sweats
  • Mood changes associated with the menopausal transition
  • Osteoporosis prevention in those at elevated fracture risk who cannot tolerate other agents

Diagnosis of menopause is clinical in most cases. In Canada, LifeLabs and Dynacare offer FSH and estradiol panels, though SOGC guidance notes that hormone testing is not required to diagnose natural menopause in women over 45 with typical symptoms.

HRT types at a glance

TypeFormulationBest suited for
Systemic estrogen + progestogenOral pill, transdermal patch, gel, sprayVasomotor symptoms; intact uterus
Systemic estrogen alonePatch, gel, oralVasomotor symptoms; post-hysterectomy
Low-dose vaginal estrogenCream, tablet, ringGSM only; minimal systemic absorption
Bioidentical micronized progesteroneOral (e.g., Prometrium)Uterine protection; may improve sleep
TiboloneOral synthetic steroidNot available in Canada

Treatment options

Systemic therapy addresses whole-body symptoms. Transdermal estradiol (patch or gel) is generally preferred over oral estrogen for women with cardiovascular risk factors or a personal history of migraines with aura, because it bypasses first-pass hepatic metabolism and carries a lower venous thromboembolism (VTE) risk than oral formulations. The Women's Health Initiative (WHI, 2002) found a small absolute increase in breast cancer risk with combined estrogen-progestin therapy (approximately 8 additional cases per 10,000 person-years); estrogen-alone therapy in post-hysterectomy participants did not show a statistically significant increase.

Micronized progesterone (available in Canada as Prometrium) appears to carry a lower breast cancer and VTE risk than synthetic progestins based on observational data, though head-to-head randomized trial evidence remains limited.

Low-dose vaginal estrogen is appropriate when symptoms are confined to the genitourinary tract. Systemic absorption is minimal, and it is generally considered safe even in breast cancer survivors, though oncology consultation is advised.

In Canada, most systemic HRT formulations are covered under provincial drug benefit programs for eligible patients — coverage criteria vary by province. Clinicians can also prescribe through virtual platforms such as Felix, Cleo, Maple, or Phoenix, which serve patients across multiple provinces.

When to see a clinician in Canada

Seek assessment from a family physician, gynecologist, or menopause specialist if:

  • Hot flashes or night sweats are disrupting sleep or daily function
  • Vaginal dryness is causing pain with intercourse or recurrent UTIs
  • Menopause occurred before age 45 (premature ovarian insufficiency warrants prompt HRT discussion to protect bone and cardiovascular health)
  • You have questions about personal risk given a family history of breast cancer, blood clots, or cardiovascular disease

The SOGC's Menopause Consensus (updated 2021) and the Menopause Society's 2023 position statement both support offering HRT to healthy symptomatic individuals under 60 after individualized risk discussion. The Menopause Society of Canada and the Canadian Menopause Society are additional resources for finding certified menopause practitioners.

Limitations and open questions

Research is still emerging on several important areas:

  • Long-term cardiovascular effects of transdermal versus oral estrogen have not been fully characterized in large randomized trials; most cardiovascular data come from the WHI, which used oral conjugated equine estrogen and medroxyprogesterone acetate — formulations less commonly prescribed today.
  • Breast cancer risk with micronized progesterone versus synthetic progestins remains based largely on observational cohort data (notably the French E3N study); a definitive randomized trial has not been completed.
  • Duration of use beyond 5–7 years is an area of active debate. Health Canada has not issued a maximum duration guideline; individualized annual review is recommended.
  • HRT in breast cancer survivors — evidence on safety is conflicting, and most guidelines advise caution or avoidance of systemic therapy pending further trial data.
  • Gender-diverse and transgender patients may use hormone therapy under different protocols; the evidence base for menopausal HRT does not directly apply to gender-affirming hormone therapy, and clinicians should consult specialized guidelines.

FAQs

What is the difference between HRT and MHT?

HRT (hormone replacement therapy) and MHT (menopausal hormone therapy) refer to the same treatment — estrogen, with or without a progestogen, prescribed to manage menopause symptoms. MHT is the term now preferred by most professional societies, including the Menopause Society and SOGC, because it more accurately describes the therapy's purpose. In everyday clinical use in Canada, both terms appear on prescriptions and drug benefit forms.

Is HRT safe, and what are the main risks?

For healthy individuals who start HRT before age 60 or within 10 years of menopause, current evidence suggests benefits typically outweigh risks. The main risks include a small increase in breast cancer with combined estrogen-progestogen therapy (approximately 8 extra cases per 10,000 person-years in the WHI trial), a modestly elevated VTE risk with oral — but not transdermal — estrogen, and a slight stroke risk increase at higher oral doses. Estrogen-alone therapy in post-hysterectomy patients did not show a statistically significant breast cancer increase in the WHI. Risk is highly individual and should be reviewed annually with a clinician.

Is HRT covered by provincial drug plans in Canada?

Coverage varies by province and by specific formulation. In Ontario, for example, several estradiol patches and oral micronized progesterone (Prometrium) are listed on the Ontario Drug Benefit formulary for eligible recipients. British Columbia's PharmaCare and Alberta's drug benefit program similarly list common HRT products, though prior authorization may be required for some formulations. Patients should confirm coverage with their provincial formulary or pharmacist, as listing status changes periodically.

How is transdermal HRT different from oral HRT?

Transdermal estradiol (patch, gel, or spray) is absorbed through the skin directly into the bloodstream, bypassing the liver. This means it does not raise clotting factors the way oral estrogen does, giving it a lower venous thromboembolism risk — an important consideration for women with obesity, migraines with aura, or a personal or family history of blood clots. Oral estrogen is convenient and well-studied but carries a roughly 2-fold higher VTE risk compared to transdermal routes based on observational data. Both routes are similarly effective for hot flash relief at equivalent doses.

Can HRT be started during perimenopause, or only after menopause?

HRT can be initiated during perimenopause — the transitional phase before the final menstrual period — when symptoms are already affecting quality of life. SOGC guidance acknowledges that perimenopausal individuals may benefit from hormonal management, and low-dose combined oral contraceptives are sometimes used in this window as an alternative. Starting systemic HRT during perimenopause requires contraception discussion, as ovulation can still occur. The 'timing hypothesis' benefit window begins from the onset of the menopausal transition, not strictly from the final period.

Sources

All glossary termsUpdated 2026-05-22