Hormone therapy is the most effective treatment for hot flashes, night sweats, and many other symptoms of perimenopause and menopause. And for twenty years, many women who could have benefited from it were denied access—or scared away—because of a study that was badly misinterpreted.

Let me tell you what actually happened, and what we now know.

The WHI Controversy

In 2002, the Women's Health Initiative study was halted early and its results announced in a press conference that terrified women and doctors alike. Headlines screamed about increased breast cancer, heart attacks, strokes.

Hormone therapy use plummeted by 50% overnight. An entire generation of women suffered through symptoms they didn’t need to suffer through.

Here’s what got lost in the panic:

The study population was wrong for the question. The average age of participants was 63. Many were more than a decade past menopause. This is completely different from treating a 48-year-old in perimenopause.

The hormones used were specific formulations. The study used only oral conjugated equine estrogen (Premarin) and medroxyprogesterone acetate (Provera). We now know these aren’t optimal—but the results were applied to all hormone therapy.

The absolute risks were small. The headlines focused on relative risk increases that sounded alarming but represented very small absolute numbers.

Benefits were ignored. The study actually showed decreased fractures, decreased colorectal cancer, and—in the estrogen-only arm—no increased breast cancer risk.

The Reassessment (2024-2025)

Twenty years of subsequent research, including major analyses from Nature, Yale, the Korean Society of Menopause, and the International Menopause Society, have dramatically shifted the picture:

The timing hypothesis is validated. Starting hormone therapy early—within 10 years of menopause, or under age 60—produces different effects than starting late. Early initiation is protective for the heart; late initiation may not be. I’ll be honest that the trials don’t all sing the same note: in KEEPS, four years of hormone therapy started near menopause neither slowed nor sped the thickening of artery walls—no clear protection, but no harm either.

Transdermal estrogen is safer than oral. Patches, gels, and sprays bypass the liver, don’t increase clotting risk, and don’t raise blood pressure like oral estrogen can.

Micronized progesterone is preferred. Unlike synthetic progestins, micronized progesterone (Prometrium) has a better safety profile, helps with sleep, and may have a lower impact on breast cancer risk.

The FDA has changed its stance. In late 2025 the FDA announced it would remove the boxed warnings that scared women and providers for two decades—and in February 2026 the first revised labels were approved, including for vaginal estrogen.

Current Evidence

Outcome	Finding	Timing Matters?
Cardiovascular	Started early: safe for the heart, possibly protective; started late: potentially harmful	Yes—within 10 years of menopause
Breast cancer	Small absolute risk increase with combined estrogen + progestin; estrogen-only may not increase risk	Duration matters
Bone health	Prevents fractures; effect is maintained while taking HT	Any age
Cognition	Largest analyses find no effect on dementia risk—neither protection nor harm	Not a reason to start or avoid
Depression	Can help perimenopausal depression—average benefit is modest	During transition
Hot flashes	Most effective treatment available	Any stage
Vaginal symptoms	Highly effective; local estrogen is safe for most	Any stage

Types of Hormone Therapy

Estrogen Delivery

Transdermal (patches, gels, sprays): Generally preferred. Lower risk of blood clots because it bypasses the liver. More stable blood levels than oral. Options include patches (Climara, Vivelle-Dot), gels (EstroGel, Divigel), and sprays (Evamist).

Oral pills: Higher risk of blood clots and stroke. Affects liver proteins (including clotting factors). May work better for some women; metabolism varies.

Vaginal (local): For vaginal and urinary symptoms specifically. Minimal systemic absorption—safe for many women who can’t take systemic hormones, including many breast cancer survivors. Comes as creams, tablets, rings, or suppositories.

And a new estrogen is on the horizon. In March 2026, Europe approved the first hormone therapy built on estetrol—a fourth, naturally occurring estrogen. In its phase 3 trial it clearly reduced hot flashes compared to placebo. It isn’t available in the US, and it was studied in postmenopausal women rather than during perimenopause—but after decades of the same few options, it’s good to see genuinely new ones arriving.

Progestogen (required if you have a uterus)

If you have a uterus, you need progestogen to protect the uterine lining from estrogen stimulation. Without it, estrogen alone increases risk of endometrial cancer.

Micronized progesterone (Prometrium): Body-identical progesterone. Better side effect profile than synthetic progestins. May help sleep (take at bedtime). Probably lower breast cancer risk than synthetic progestins.

Synthetic progestins (MPA, norethindrone): More side effects—mood changes, bloating—for some women. The type used in the WHI study.

Hormonal IUD (Mirena): Provides local progestogen protection to the uterus. Can be combined with estrogen therapy. Good option if you also need contraception (yes, you may still need contraception during perimenopause).

Testosterone

Testosterone isn’t FDA-approved for women in the US, but it’s used off-label and prescribed routinely in other countries for low libido, fatigue, and wellbeing. If this interests you, discuss it with your provider—preferably one knowledgeable about menopause.

Who Can and Can’t Use Hormone Therapy

Generally good candidates:

Women under 60 or within 10 years of menopause
Significant symptoms affecting quality of life
No contraindications (see below)

Absolute contraindications:

History of breast cancer (though local vaginal estrogen is often still safe—discuss with your oncologist)
History of blood clots (though transdermal may be considered)
Active liver disease
Unexplained vaginal bleeding
Known or suspected pregnancy

Situations requiring careful consideration:

Family history of breast cancer
History of stroke or heart disease
Migraine with aura
Gallbladder disease
High triglycerides

If you have a complex medical history, find a provider who specializes in menopause—not one who reflexively says no because they’re not comfortable with the nuances.

Starting Hormone Therapy

Some practical considerations:

It takes time to work. Full effect for hot flashes may take 4-8 weeks. Don’t give up too quickly.

Dosing may need adjustment. Many women start on a standard dose and adjust based on response. Some need more; some need less.

There may be side effects initially. Breast tenderness, bloating, spotting—these often settle within a few months. Bleeding that persists, or that shows up new after things had settled, deserves a proper check—UK guidance now has a formal referral pathway for exactly this—so tell your provider rather than waiting it out.

You don’t have to stay on it forever. The decision about duration is individual. Some women use it for a few years during the worst of the transition; others stay on it longer. There’s no mandatory stop date.

Stopping should be gradual. Abruptly stopping can trigger a return of symptoms. Tapering is usually better.

Finding a Knowledgeable Provider

Many providers are still operating on outdated WHI-era fears. You deserve someone who:

Understands the timing hypothesis
Knows the difference between formulations
Takes your symptoms seriously
Discusses both risks AND benefits
Treats you as a partner in decision-making

See Finding Care for how to find and advocate with providers.

I hold no allegiance to hormone therapy as the only answer. For some women, other approaches work better or are more appropriate. For others, hormones are exactly what they need. What I want is for you to have accurate information and the freedom to choose—not to be scared away from an effective treatment by twenty-year-old headlines.