The present invention provides novel methods of inhibiting bone loss comprising administering to a mammal in need of such treatment an effective amount of a compound of formula I ##STR1## wherein R.sup.1 and R.sup.2 may be the same or different provided that, when R.sup.1 and R.sup.2 are the same, each is a methyl or ethyl group, and, when R.sup.1 and R.sup.2 are different, one of them is a methyl or ethyl group and the other is hydrogen or a benzyl group; or a pharmaceutically acceptable salt thereof; together with a progestin.