Conclusions and Relevance This systematic review and meta- analysis did not show a significant beneficial or detrimental association of HT with muscle mass .
Importance Hormone therapy ( HT ) has been suggested for protection against age-related muscle weakness in women .
However , the potential for HT-associated health risks necessitates a better underst and ing of the direction and magnitude of the association between HT and health outcomes , such as lean body mass ( LBM ) .
Objective To determine whether HT was associated with reduced LBM loss compared with not receiving HT  among postmenopausal women aged 50 years and older .
The Minimum Effective Dose of Estrogen for Prevention of Postmenopausal Bone Loss
In a controlled single blind study to determine the minimal effective dose of estrogen for protection against bone loss , conjugated equine estrogens in doses of 0.625 and 1.25 mg per day were equally effective in reducing  bone loss in postmenopausal and oophorectomized women when bone mass was estimated by single-photon absorptiometry or radiogrammetry . Daily dose levels of less than 0.625 mg were essentially ineffective . Fifty percent response level was calculated to be 0.45 mg per day . Concomitant biochemical effects , reduction in urine calcium and hydroxyproline , were compatible with the observed effects on bone mineral
Conclusions and Relevance This systematic review and meta- analysis did not show a significant beneficial or detrimental association of HT with muscle mass .
Importance Hormone therapy ( HT ) has been suggested for protection against age-related muscle weakness in women .
However , the potential for HT-associated health risks necessitates a better underst and ing of the direction and magnitude of the association between HT and health outcomes , such as lean body mass ( LBM ) .
Objective To determine whether HT was associated with reduced LBM loss compared with not receiving HT  among postmenopausal women aged 50 years and older .