Hormone Replacement Therapy (HRT)

Hormone Replacement Therapy (HRT), increasingly called Menopausal Hormone Therapy (MHT) in current clinical guidelines, is the use of estrogen (plus progestin or progesterone in women with a uterus) to relieve symptoms of perimenopause and menopause. HRT is a different drug class from hormonal contraception in dose, delivery, and clinical purpose, despite the surface similarity of both involving exogenous hormones.

This is informational, not medical advice. Talk to your provider if you are considering HRT, especially if you have a personal or strong family history of breast cancer, blood clots, stroke, or coronary disease, which all affect the risk-benefit calculation.

What HRT is for

HRT addresses the symptoms produced by declining ovarian estrogen production:

  • Vasomotor symptoms. Hot flashes, night sweats. The strongest indication and most effective use case.
  • Genitourinary syndrome of menopause. Vaginal dryness, painful intercourse, urinary symptoms.
  • Sleep disruption related to menopausal changes.
  • Mood changes in perimenopause and early menopause.
  • Bone density preservation. Reduces osteoporosis risk.

HRT is not a routine longevity intervention or general anti-aging treatment, despite some popular framings. The evidence supports it as a symptom-management tool that, when started early in menopause and personalized appropriately, also has likely cardiovascular and bone benefits.

How HRT differs from birth control

This is a common point of confusion. The differences:

  • Dose. HRT uses much lower hormone doses than combined hormonal contraceptives. Roughly 1/4 to 1/6 the estrogen dose of typical birth control pills.
  • Hormone form. Modern HRT typically uses 17-beta-estradiol (bioidentical to natural estradiol), not the synthetic ethinyl estradiol in birth control pills.
  • Progestogen choice. HRT can use micronized progesterone (bioidentical) or various synthetic progestins. Birth control uses synthetic progestins exclusively.
  • Intent. HRT replaces what the body no longer makes. Birth control suppresses what the body would otherwise make, plus adds back lower levels to maintain a withdrawal bleed.
  • Effect on cycles. HRT does not suppress ovulation in perimenopausal women still cycling; you still need contraception until menopause is confirmed. Birth control suppresses ovulation.

A woman in late perimenopause who needs contraception and symptom relief sometimes uses a low-dose combined pill for both purposes. Otherwise, the two drug classes serve different purposes.

The main HRT types

The current standard options:

Estrogen delivery:

  • Oral estradiol. Standard pills. First-pass liver metabolism increases SHBG, affects clotting factors, can affect mood and energy in some users.
  • Transdermal estradiol (patch, gel, spray). Bypasses the liver. Lower thrombotic risk. Generally preferred for women with cardiovascular risk factors, migraine with aura, or higher BMI.
  • Vaginal estradiol (cream, tablet, ring). Local effect on genitourinary symptoms. Systemic absorption is minimal at standard doses.

Progestogen delivery (for women with a uterus):

  • Oral micronized progesterone (Prometrium, Utrogestan). Bioidentical. Calming, sleep-promoting effect for many women. Generally preferred for tolerability.
  • Synthetic progestins (medroxyprogesterone, norethindrone, others). Older formulations. Some have unfavorable cardiovascular and mood profiles.
  • Hormonal IUD (levonorgestrel IUD). Can serve the endometrial protection role for some women.

Combined preparations that include both estrogen and progestin are also available.

Cyclic versus continuous regimens

Two main schedules:

  • Continuous combined. Estrogen and progestogen both given daily. No withdrawal bleed. Common for postmenopausal women. The expected pattern is no bleeding after the first few months.
  • Cyclic (sequential). Estrogen daily, progestogen for 10 to 14 days per month. Produces a monthly withdrawal bleed similar to a period. More commonly used in perimenopause when natural cycling has not stopped.

What the evidence actually says

The Women's Health Initiative (WHI, 2002) initially produced a wave of HRT avoidance based on findings of increased breast cancer and cardiovascular events. Subsequent reanalysis and newer evidence has changed the picture:

  • Timing matters. Starting HRT within 10 years of menopause onset (or before age 60) has a favorable risk-benefit profile for most women. Starting later is more uncertain.
  • Form matters. Transdermal estrogen has lower thrombotic and stroke risk than oral. Micronized progesterone has lower breast cancer risk than medroxyprogesterone (the form used in WHI).
  • Duration. Short-term use (under 5 years) has minimal breast cancer risk increase. Longer-term use has a small absolute increase that has to be weighed against benefits.
  • Estrogen-only HRT (for women without a uterus) does not appear to increase breast cancer risk in the same way combined therapy does in some analyses.

The current professional society position (NAMS, IMS, ACOG): HRT is appropriate for most healthy perimenopausal and early-postmenopausal women with symptoms, with shared decision-making and individualized dosing.

Who is a candidate

Generally appropriate candidates:

  • Women under 60 or within 10 years of menopause onset.
  • Significant vasomotor symptoms (hot flashes, night sweats) interfering with sleep or function.
  • Genitourinary symptoms (vaginal estrogen alone is reasonable for isolated symptoms).
  • Premature ovarian insufficiency (POI) or surgical menopause. HRT is generally recommended until natural menopausal age (~51) regardless of symptoms.

Generally not appropriate candidates:

  • History of estrogen-receptor-positive breast cancer.
  • History of venous thromboembolism (depends on type and timing).
  • Active liver disease.
  • Unexplained vaginal bleeding (work up first).
  • Active coronary artery disease (relative contraindication, case-by-case).

What does not work as well

A few HRT-adjacent claims to be skeptical of:

  • "Bioidentical compounded HRT" from specialty pharmacies. The term "bioidentical" is also true of FDA-approved estradiol and progesterone. Custom-compounded preparations are unregulated, dose-variable, and not better-evidenced than standard FDA-approved bioidentical options.
  • Salivary hormone testing to "dose" HRT. Not clinically validated. Symptom response and clinical judgment guide dosing.
  • HRT as primary osteoporosis treatment in women without menopausal symptoms. Specific bone-targeted therapies are usually first-line for osteoporosis alone.

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