What's her purpose using it? Is her diet on? Is she consistent with her training?
Does she know anything about it? Get her on the boards (specifically the Ladies' Board) so she can learn more and make the decision herself.
Education is power my friend. And there are plenty of women who have been screwed over by being put on gear by their bf's. Not saying you are screwing her over, but often they dont' know what they are getting into.