Menopause and hormone therapy: what the evidence says

Menopause guidance has been rewritten more than once since the early 2000s, and it shows in how carefully current guidelines are worded. In the UK, the National Institute for Health and Care Excellence (NICE) publishes a national guideline on menopause identification and management, known as NG23, first published in 2015 and periodically updated as new evidence and recommendations are added.^[1] In the United States, The Menopause Society (known as the North American Menopause Society, or NAMS, until it changed its name in 2023) publishes a hormone therapy position statement developed by an advisory panel of clinicians and researchers who review the trial evidence and reach consensus recommendations; the most recent version was published in 2022.^[2]

Despite covering different health systems, the two sources land on the same broad shape of advice: hormone therapy (HT) is the most effective treatment for the vasomotor symptoms of menopause, the balance of benefit and risk depends heavily on when it is started and how it is taken, and it should be individualized rather than applied as a blanket recommendation or a blanket avoidance.

Vasomotor symptoms, hot flushes and night sweats, are the best-known feature of the menopausal transition, and they are the symptom hormone therapy treats most reliably. NICE recommends offering HT to people with vasomotor symptoms associated with menopause.^[1] The Menopause Society goes further, stating plainly that hormone therapy remains the most effective treatment for vasomotor symptoms and for the genitourinary syndrome of menopause (the vaginal and urinary symptoms covered later in this article).^[2]

That does not mean it is the only option. People who cannot or would prefer not to use hormone therapy have non-hormonal alternatives to discuss with a clinician. What the evidence supports clearly is that among available treatments, HT has the strongest and most consistent effect on hot flushes and night sweats.

To understand why current guidance is so careful about timing, it helps to know why the advice changed in the first place. In 2002, the Women’s Health Initiative (WHI), a large US randomized controlled trial, stopped the combined estrogen-plus-progestin arm of its study early after an interim analysis found increased risks of breast cancer, stroke, blood clots, and coronary heart disease among participants taking it, compared with placebo.^[3] The trial had enrolled postmenopausal women aged 50 to 79, with many participants well past their final period by the time they enrolled, and the finding triggered a sharp, near-overnight drop in hormone therapy prescribing worldwide.

Later analysis of the WHI data by age and time since menopause, along with other research since, reshaped the picture into what is now often called the “timing hypothesis.” The Menopause Society’s position statement reflects this directly: for healthy, symptomatic people younger than 60 or within 10 years of menopause onset, the benefits of hormone therapy on symptoms and bone density generally outweigh the risks. For people who start hormone therapy more than 10 years after menopause onset, or after age 60, the balance is considered less favorable, largely because the absolute risks of heart disease, stroke, and blood clots rise with age regardless of hormone use.^[2]

Regimen. NICE distinguishes between combined estrogen-progestogen therapy and estrogen-only therapy. Breast-cancer risk increases with combined HT, and that increase grows the longer it is used, while estrogen-only HT carries little to no increase in breast-cancer risk.^[1] This is also why the two regimens are used in different people: a progestogen is generally added to protect the uterine lining, so people with a uterus typically take combined therapy, while people without a uterus (after a hysterectomy) can typically use estrogen alone.

Route. How estrogen is delivered matters for clot risk specifically. NICE advises considering transdermal rather than oral HT for people at increased risk of venous thromboembolism (VTE, or blood clots), noting that VTE risk is increased with oral HT but is not meaningfully increased with transdermal HT (patches or gels).^[1]

Vaginal dryness, discomfort, and some urinary symptoms (together often called the genitourinary syndrome of menopause) are common and tend to persist, or worsen, well beyond the years when hot flushes typically ease. NICE recommends offering vaginal estrogen for these symptoms and reviewing use regularly, and notes it can be used on its own or alongside non-hormonal moisturizers or lubricants.^[1]

Low-dose vaginal estrogen acts mostly locally, with minimal absorption into the bloodstream. That is why it is treated differently from systemic HT: it generally does not require an added progestogen for endometrial protection, even in people with a uterus, and it can typically continue for as long as symptoms warrant, since symptoms tend to return once treatment stops.

One of NICE’s clearer statements addresses a use that was common in the past: taking HT purely to ward off future illness rather than to treat current symptoms. NICE advises against offering combined or estrogen-only HT for primary or secondary prevention of cardiovascular disease, and against offering it for the purpose of dementia prevention.^[1]

This does not cancel out HT’s other established benefits, including symptom relief and the Menopause Society’s note that it helps prevent bone loss in the people who take it for symptoms.^[2] The distinction is about the reason for starting treatment: managing menopausal symptoms in someone who has them is a different decision from prescribing HT to someone without symptoms on the theory that it will prevent disease later.

A personal history of, or high risk for, certain cancers changes the calculation substantially. NICE recommends that people with menopausal symptoms who have a personal history of, or are at high risk of, breast cancer be given full information on their management options and referred to a healthcare professional with expertise in menopause, rather than starting HT through routine care.^[1]If someone is diagnosed with breast cancer while already taking systemic HT, NICE’s guidance points toward stopping it, in line with dedicated breast-cancer guidance.^[1]

Premature ovarian insufficiency (menopause before age 40) is a distinct situation with different considerations. NICE recommends that people in this position start hormonal treatment, either HT or a combined hormonal contraceptive, and continue it until at least the average age of natural menopause, unless it is contraindicated, because the health context of early estrogen loss differs from menopause at a typical age.^[1]

Most people who use hormone therapy do so without serious complications, but a smaller set of symptoms warrant prompt medical assessment rather than waiting for a routine follow-up appointment.

Outside of these patterns, the guidance above applies: hormone therapy is generally well tolerated, and the right regimen, route, and duration are a conversation to have with a clinician who knows your health history.

Menopausal hormone therapy has gone through a genuine arc: widely used, then largely abandoned after 2002, then reintroduced with real nuance as the timing hypothesis and regimen-specific risk data emerged. NICE and The Menopause Society now converge on a picture that is more useful than either the earlier blanket enthusiasm or the blanket avoidance that followed it: HT works well for vasomotor and genitourinary symptoms, timing and regimen meaningfully change the risk profile, and it is not a tool for preventing disease in people without symptoms. See how we grade the strength of evidence across topics in our editorial and evidence standards, and browse the rest of our Hormone & Vitality coverage as it grows.

None of this replaces an individual conversation with a clinician who knows your symptoms, history, and preferences. It reflects what current guidelines actually say, which is more measured, and more genuinely useful, than either the reassurance or the alarm that has surrounded this topic at different points over the last twenty-five years.