Without entering into a debate about the virtues of legal prohormones/prosteroids vs. illegal steroids (you must use your own mind and judgment about these things since there are often, but not always, a lot of uniformed biases and other agendas that enter into the "they don't work but will turn you in to a man"- type of comments
), I will suggest you try Biotest's Mag-10 at no more than 45% of the recommended, single daily dose for males.
I know one 40+ y/o female who has had great success with strength and lean body weight gains (without any of the virilizing effects that some people swear will happen just by looking at this stuff!) using two different protocols.
First cycle, she used 4 ml./day for 14 days. After taking two weeks off, she started a second cycle using 2 ml./day for approximately 6 weeks (since she experienced no virilizing side effects at 4 ml./day, there would certainly be none at 2 ml./day and since she is a woman, suppresion of natural testosterone levels on a longer cycle at a lesser dose is virtually a non-issue).
It's been a couple of months since the second cycle, but she has retained both her strength and lean body weight gains. Of course she increased her protein intake to a minumum of 1 gram per pound of body weight while "on," which is very important when using anabolic compounds, be they legal or illegal.
I'm sure there are other legal products that are effective, but Mag-10 is the one that I have firsthand knowledge of.
Good luck with whatever you decide to use...