I am currently taking Progesterone regularly since my accident and I think it is definitely helping. They test your levels by doing an at home saliva test (gross, but you spit into a small tube several times a day and then send tubes to the lab, not bad really!) Mine were low and probably were a little low anyway now that I am 40. You take it as a cream that is dispensed in measured doses from a syringe tube (NO needle, it goes on topically to places like behind your knees or forearms).

I slacked off on it for a couple of weeks after taking it several months and noticed a decline in progress for sure. For me, it helps with moods, less depression, helps improve sleep and perhaps keep some weight gain away.

Just wanted to add my personal experience to back up Mark's post. Most women probably need progesterone, esp if you eat a "typical american diet", but it's best to get it checked by someone who knows bio identical hormones.