What is the difference between estrogen-only and combined HRT?

Last reviewed July 6, 2026 by Dr. Sapna Jadhav, General Physician. Sources from ACOG, NHS, Mayo Clinic, CDC, NICE, NIH, Cochrane, and peer-reviewed journals.

Bottom lineEstrogen-only HRT is for women who have had a hysterectomy; combined HRT adds progesterone because estrogen alone overstimulates the womb lining and raises endometrial cancer risk - so anyone with a uterus takes both, either sequentially (with a monthly bleed, during perimenopause) or continuously (no bleed, once 12 months past the final period).

The difference comes down to one question: do you have a uterus?

Estrogen-only HRT

Contains just estrogen - the hormone that actually relieves hot flashes, night sweats, mood symptoms, and vaginal dryness. It is prescribed for women who have had a hysterectomy, because with no womb there is no womb lining to protect.

Estrogen-only HRT is the simplest form and has the most favorable risk profile in the major studies - the Women's Health Initiative found no meaningful increase in breast cancer risk with estrogen alone.

Combined HRT

Contains estrogen plus progesterone (or a synthetic progestogen). It is prescribed for women who still have their uterus, because estrogen taken alone stimulates the womb lining to thicken, which raises the risk of endometrial cancer over time. Progesterone's job is to keep the lining safe.

Combined HRT comes in two patterns:

• Sequential (cyclical): estrogen daily, progesterone for 10-14 days per cycle, with a monthly bleed - the usual start during perimenopause, while you still have periods.
• Continuous combined: both hormones every day, no scheduled bleed - for women at least 12 months past their final period.

Which one you will be offered

• Had a hysterectomy → estrogen-only.
• Have a uterus, still having (or recently had) periods → sequential combined.
• Have a uterus, 12+ months past your last period → continuous combined.

A hormonal IUD (like Mirena) can also supply the progesterone side while providing contraception - useful in perimenopause.

This is general information, not medical advice. Read the full guide: starting HRT and what to expect.

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