What are the specific reasons you are considering this procedure-- for libido reduction, or for the health benefits, or for the ostensible life expectancy increase this procedure might provide? You don't have to answer these questions here, but I'm posting them to make sure that you yourself know your own specific reasons for wanting to be castrated; if you know them, you can focus your research on those areas.

Regarding bone density, I'm not sure how much chemical castration hurts you. In any case, I seem to vaguely recall that there's other stuff you can do to maintain bone density as you age (some of which women tend to pay more attention to then men), so do look into that if you decide to follow through with castration.

It's been a while since I looked into this, and I looked into the stuff on physical, rather than chemical castration, anyways (I don't have a good intuition on how much the two differ on most axes, since I didn't ever look into the chemical castration side of things much). What I'm trying to say is that it may be wise to set aside the research you find on physical castration if you are committed to going the chemical route, unless you're able to convince yourself that it's relevant.

Now that I've disclaimed that which I needed to disclaim, in the spirit of blatant self-promotion, there's always this post.