Is Hormone Replacement Therapy (HRT) Safe? The Latest Science Explained

HRT has had a complicated reputation, but the science has shifted significantly. For most women under 60, hormone replacement therapy is now considered safe and effective, and the FDA removed its longstanding black box warning in 2025. Here is what you need to know.

For most women under 60 or within ten years of menopause onset, hormone replacement therapy (HRT) is now considered safe and is recommended by leading medical bodies including the British Menopause Society and the Menopause Society in the US. The science has shifted significantly since the early 2000s, when a large study caused widespread fear about HRT risks. What the latest research shows is more nuanced, and far more reassuring, than the headlines of twenty years ago.

Why was HRT thought to be dangerous?

In 2002, the Women's Health Initiative (WHI) published results suggesting HRT increased the risk of breast cancer, heart disease, and stroke. The study caused a dramatic drop in HRT prescriptions globally, and many women spent the following two decades managing menopause symptoms without treatment.

The problem, later identified by researchers, was that the WHI study used older synthetic hormones, administered them to women who were significantly older (average age 63) and many years past menopause, and combined oestrogen with a specific progestogen that carried its own risks. The findings were never applicable to the majority of women seeking HRT at perimenopause or early menopause.

What does the latest research show?

A large body of evidence published since 2010 has substantially rehabilitated HRT. Key findings include:

For women who start HRT within ten years of menopause or before age 60, cardiovascular risk is low and may even be protective
Body-identical oestrogen delivered via patch or gel does not carry the blood clot risk associated with oral oestrogen tablets
Micronised progesterone, a body-identical progestogen, appears to carry a lower breast cancer risk than synthetic progestogens used in older studies
The 2025 FDA decision to remove the longstanding black box warning from HRT packaging reflects the weight of this updated evidence

Research published in the Lancet and the New England Journal of Medicine supports HRT as a first-line treatment for vasomotor symptoms, genitourinary symptoms, and prevention of bone density loss in appropriate candidates.

Who is HRT recommended for?

HRT is generally recommended for women who:

Are in perimenopause or early menopause (within ten years of their last period or under age 60) and experiencing bothersome symptoms
Have had a premature menopause (before age 45) or surgical menopause, where HRT is typically advised until at least the average age of natural menopause
Are at elevated risk of osteoporosis and want to protect bone density

HRT is generally not recommended for women with a personal history of hormone receptor-positive breast cancer, unexplained vaginal bleeding, active liver disease, or a recent cardiovascular event. A conversation with your GP or menopause specialist is essential to assess your individual risk profile. You can read more about the hormonal transition in our guide to perimenopause and when it starts.

What are the benefits of HRT?

For appropriate candidates, HRT can:

Significantly reduce hot flushes and night sweats (up to 90% reduction in frequency in many studies)
Improve sleep quality disrupted by vasomotor symptoms
Reduce vaginal dryness, pain during sex, and urinary symptoms
Protect bone density and reduce fracture risk
Improve mood, cognitive clarity, and energy during the early menopause transition
Potentially reduce cardiovascular disease risk when started early in the menopause transition

Emerging research is also examining HRT's role in reducing long-term Alzheimer's risk in women. Two-thirds of Alzheimer's patients are female, and oestrogen plays a significant neuroprotective role. The 2026 research agenda in women's health has made brain health during the menopause transition a priority area.

What are the risks of HRT?

All HRT carries some level of risk, and the balance differs by individual:

Combined HRT (oestrogen and progestogen) is associated with a small increase in breast cancer risk with longer use, though the absolute risk for most women is modest and comparable to other lifestyle factors such as alcohol consumption
Oral oestrogen tablets increase blood clot risk; transdermal (patch or gel) oestrogen does not carry the same risk
Micronised progesterone has a more favourable safety profile than older synthetic progestogens

The framing that matters: for most women with significant menopause symptoms, the risks of untreated menopause (bone loss, cardiovascular changes, sleep disruption, and cognitive effects) often outweigh the risks of modern HRT. This is a decision best made with an informed clinician, not one made from fear of twenty-year-old data.

How can I track whether HRT is working for me?

Symptom tracking is essential when starting HRT. It lets you document baseline symptoms before treatment, monitor changes week by week, and give your clinician accurate information at follow-up appointments rather than relying on memory. Apps like Solu can help you log sleep quality, energy, mood, and physical symptoms in a structured way that is easy to share with your healthcare provider.

Most women notice meaningful improvement in vasomotor symptoms within four to twelve weeks. If symptoms persist or new ones emerge, tracking data makes it much easier to adjust the type, dose, or delivery method of HRT in collaboration with your clinician.