Hormone therapy is no shield against menopausal muscle loss

Women lose muscle as they age, and the years around menopause are often when that loss accelerates, with real consequences for strength, mobility and independence later in life. Hormone therapy has been suggested as a way to protect against this age-related muscle weakness, which would make it attractive beyond its established use for menopausal symptoms. But hormone therapy also carries potential health risks, so the trade-off only makes sense if the muscle benefit is real and meaningful. That is the question this review set out to settle: does hormone therapy actually slow the loss of lean body mass in postmenopausal women, and by how much?

The researchers swept five medical databases from their inception until April 25, 2018, screening 8961 studies and keeping 12 randomised trials that met their criteria, with 4474 recruited participants in total. All were postmenopausal women aged 50 and older, with a mean age of 59.0 years; women from hospitals, long-term care or with specific diseases were excluded. Across 22 hormone therapy arms, 15 used an estrogen-progesterone combination and 7 used estrogen only, with controls receiving placebo or nothing. The outcome was the absolute change in lean body mass in kilograms, measured by body scans, over a median follow-up of 2 years, ranging from 6 months to 6 years.

Overall, women on hormone therapy lost 0.06 kg less lean body mass than controls, a difference that was not statistically significant. The individual trial arms were split: 7 showed a loss of lean mass on hormone therapy while 14 leaned protective, but nothing decisive emerged in either direction. The null result held when the data were sliced by treatment type and dosage, follow-up duration, time since menopause, study quality and the way lean mass was measured, with the range across all those strata running from 0.06 kg more lost to 0.20 kg less lost on hormone therapy. The reviewers graded the overall quality of the evidence as low.

This pooled analysis pushes back on the suggestion that hormone therapy can protect women against age-related muscle weakness, finding neither a meaningful benefit nor a meaningful harm to lean mass. The consistency of the null across doses, formulations and durations makes it harder to argue that a particular regimen was simply missed. The authors conclude that interventions other than hormone therapy should be explored for muscle retention in ageing women. Open questions remain: the quality of evidence was rated low, and only 2 of the included studies collected data on ethnicity, so the picture is not complete for every group of women.

If you are postmenopausal and weighing up hormone therapy, this is a reason to treat muscle preservation as a separate problem from menopause symptoms: on the pooled trial evidence, hormone therapy neither builds nor erodes lean mass in any measurable way. For women already on it, there is nothing here to suggest it is quietly costing muscle either, which is its own kind of reassurance. The broader message is that holding onto muscle through the menopausal years likely depends on other levers, and the authors themselves point towards exploring interventions beyond hormone therapy for that job.