Two headlines, 23 years apart. 2002: “Hormone replacement therapy causes breast cancer”. A study is stopped, and prescriptions collapse worldwide by up to 80 percent. 2025: the US Food and Drug Administration (FDA) removes exactly the warning that had officially confirmed this fear for two decades. In between lies one of the longest crises of trust in modern women’s medicine.
If you’re going through menopause right now or wondering whether hormone therapy is right for you, you’ve probably picked up both headlines somewhere and still aren’t any wiser. That’s understandable. Between “hormones are dangerous” and “hormones are now safe for everyone” lies the actually interesting story. That’s what we’ll look at today: calmly, with real numbers, without scaremongering and without anti-ageing promises.
What really happened in 2002
The Women’s Health Initiative (WHI) was a large randomised controlled trial, the gold standard of evidence. Its oestrogen-progestin arm was stopped early in 2002 because a safety signal appeared: 245 of 8,506 women on hormone therapy developed breast cancer, compared with 185 of 8,102 on placebo. That gave a relative risk of 1.24; in absolute terms, about eight additional cases per 10,000 woman-years.
What got lost in worldwide coverage: the participants were 63 years old on average. Many of them started hormone therapy ten to twenty years after their last period, not at the onset of symptoms in perimenopause, as most women would today. Later reanalyses broken down by age (Manson et al., JAMA 2013) painted a much more nuanced picture: for women who started at 50 to 59, the risk profile was more favourable, among other things without a significantly increased heart risk.
The WHI was neither a scandal nor “disproven”. It delivered real data for a specific, on average older population. The problem wasn’t the study; it was translating a borderline result from a particular age group into a global blanket statement for all women, of every age, with every form of hormone. The consequence of this mix-up: an estimated 50 to 80 percent drop in HRT prescriptions over two decades.
The Danish study nobody can ignore
In 2026, Danish registry researchers published the largest study on the subject so far: 876,805 women, followed for a median of 14.3 years. Result: women on hormone therapy didn’t die more often than women without it; the adjusted hazard ratio for all-cause mortality was 0.96. In women who had lost both ovaries for non-cancer reasons between the ages of 45 and 54, hormone therapy was even associated with a 27 to 34 percent lower risk of death.
Before you turn that into an anti-ageing recommendation: this is an observational study, not a randomised trial. Data on smoking status and body weight were missing, two factors that strongly influence who gets a hormone prescription in the first place. Women with healthier lifestyles are more likely to get a prescription and tend to age more healthily anyway. The study can’t rule out this “healthy user bias”. The honest interpretation is therefore: the data refute the blanket fear of higher mortality. They don’t prove a life-extending effect.
The FDA decision: a reassessment, not a new study
On 10 November 2025, the FDA announced that it would remove the highest warning level (the “black box warning”) from oestrogen-containing products: specifically, the blanket warnings about cardiovascular disease, breast cancer and “probable dementia”, the latter based mainly on a study in women over 65. A limitation that was often lost in the coverage: the warning about endometrial cancer with oestrogen-only therapy in women with an intact uterus remains.
Crucial for context: this isn’t a new study but a regulatory reassessment, based on twenty years of reanalyses, cohort studies like the Danish one and guideline work by professional societies. The new labelling explicitly adopts the so-called window or timing hypothesis: if you start therapy within ten years of your last period, the current evidence suggests a more favourable benefit-risk ratio. That’s neither “now safe for every woman” nor “the agency is ignoring the science”; it’s a more nuanced, age-dependent assessment.
Risks you should know in two numbers
Whatever the headlines sound like: a risk always needs two numbers, relative and absolute. For breast cancer: five years of oestrogen-only therapy raises the 20-year baseline risk from about 6.3 to 6.8 percent (Lancet meta-analysis, 2019); in absolute terms, about one additional case per 200 users. Combined oestrogen-progestin therapies show a larger increase than oestrogen alone.
For thrombosis, the baseline risk is 1 to 2 cases per 1,000 women per year. Oral combined therapy raises this risk two- to threefold; in absolute terms, about 2 additional cases per 1,000 woman-years (Canonico et al., 2007). Transdermal application (patch, gel), on the other hand, shows no increased thrombosis risk compared with non-users in several large cohorts. That’s exactly why the question “oral or transdermal?” is often more important than “bioidentical or synthetic?”: approved bioidentical products go through the same strict testing as any other medicine, while individually “compounded” preparations mixed in a pharmacy lack robust controlled evidence and the same quality control, according to an analysis by the US National Academies (NASEM, 2020).
Two areas where the hype is faster than the evidence
A lab value called C3 is circulating online that supposedly shows how much “younger” hormone therapy makes you. What’s real: during the transition into menopause, inflammatory and immune markers change, as documented by the large SWAN cohort study among others. So-called epigenetic clocks are also linked to “biological age”. What’s missing: hard clinical endpoints, large samples, randomised studies on causality. A commercial test is therefore not a diagnostic tool for your HRT decision; it’s the research frontier, packaged as a product.
The picture is similarly sobering for muscle maintenance. It’s biologically plausible that falling oestrogen accelerates muscle loss, and that hormone therapy might counteract it. A meta-analysis of 12 randomised controlled trials with 4,474 women did find a slightly smaller loss of fat-free mass on hormone therapy. The difference: just 0.06 kilograms, not statistically significant. A recent 2025 review (43 studies) reaches an even more sober conclusion: no consistent definition of muscle loss, and most interventions more than 20 years old. Strength training and adequate protein intake remain the far more robustly documented levers, with or without hormone therapy.
Sleep: help, yes, but not as a sleeping pill
Precision pays off with sleep too. A meta-analysis of seven studies with more than 15,000 women (Cintron et al., 2017) shows: hormone therapy improves sleep quality, but only in women who had hot flushes or night sweats at the start of the study. In women without these symptoms, the same analysis found no significant difference. The reason is the indirect pathway: hormone therapy relieves the hot flushes that disturb sleep; it isn’t a sleeping pill. If you lie awake at night without hot flushes, look at other causes and your own sleep rhythm first.
The path to your own decision
So what does this mean for you? First of all: there’s no self-test traffic light that settles suitability once and for all. But there are clear guideline criteria (German AWMF S3 guideline 015-062; NAMS/The Menopause Society 2022): for healthy, symptomatic women under 60 or within 10 years of their last period, without contraindications such as a history of breast cancer, unexplained bleeding, thrombosis, coronary heart disease or stroke, the benefit-risk ratio is usually more favourable. If you start later, it shifts. That’s the “window hypothesis”, and it describes a shift, not a hard deadline.
Good to know: there are evidence-based alternatives without hormones. Fezolinetant (approved in the US since 2023), low-dose specially approved antidepressants and gabapentin show proven effects against hot flushes, although usually smaller than hormone therapy. They aren’t a “second choice for everyone who can’t tolerate HRT” but a sensible option in their own right for many women.
Bottom line: neither fear nor hype, but a personal decision
The fear of the last twenty years wasn’t baseless for the older population studied at the time, but transferring it to all women, of every age, with every form of hormone, was. The 2026 evidence allows a more nuanced, more personal assessment: timing, symptoms, individual and family history, preferred form of application. But it doesn’t allow a blanket recommendation “for everyone”, nor a blanket rejection “for everyone”.
That’s exactly why the decision remains what it always was: a personal weighing-up, guided by your doctor, not the result of a headline, whatever the year.
If you want to tackle your menopause and your training as a whole, request your Start Plan: 60 minutes, your data, a plan for training, food and sleep that fits this phase of life.
This article is for information only and doesn’t replace medical advice. You make the decision for or against hormone replacement therapy together with your gynaecologist. Never start or stop hormone therapy on your own.
