Hormone therapy won't make muscles stronger after menopause

Muscle strength falls with age, and the years after menopause are when many women feel it most. Because oestrogen declines sharply at menopause, it has long been suspected that replacing hormones might protect or rebuild strength alongside treating menopausal symptoms. If hormone therapy genuinely strengthened muscle, it would change the calculus for millions of women weighing its benefits against its risks. Individual trials had pointed in different directions, so this review set out to establish what the randomised evidence, taken together, actually shows.

The researchers systematically searched PubMed, Web of Science, Embase and the Cochrane trials register from their start dates up to August 2019. They included only randomised controlled trials comparing hormone therapy against placebo or no therapy that measured muscle strength in postmenopausal women. Nine trials qualified, covering 2,476 women, and were judged to be of good quality overall using the Cochrane risk of bias tool. Changes in strength from baseline were extracted and pooled as standardised mean differences using a random effects model, so different strength tests could be combined.

Pooled across all nine trials, hormone therapy was not associated with any significant gain in muscle strength. The overall estimate leaned slightly positive but could not be distinguished from no effect, and the included trials disagreed with each other considerably. Importantly, the null result held however the data were sliced: by the type of hormone treatment, by the muscle group tested, and by how long treatment lasted. The authors concluded that hormone therapy either does not improve strength at all, or that any effect is too small to register as meaningful.

This is a useful corrective to the intuition that restoring oestrogen restores muscle. It does not close every door: the strong disagreement between trials means a benefit in particular subgroups or with particular regimens could be hiding inside the average, and the authors themselves allow that a very small real effect cannot be excluded. What the analysis does establish is that across the available randomised evidence, no reliable strength benefit appears. That leaves the question of how best to protect strength after menopause unanswered by hormones, at least on this evidence.

If you are postmenopausal and weighing up hormone therapy, this evidence suggests stronger muscles should not be on your list of expected benefits. Equally, if you take it for other reasons, nothing here says it weakens you; the trials simply found no improvement. Decisions about hormone therapy involve many factors this study did not examine, so it informs one specific question only. And if holding on to strength after menopause is a goal, this is a reason to think the answer lies somewhere other than hormones.