My husband's sperm is only in the 2 million range. We were told our best option for success was IVF which we did back in '06 and finally got our BFP after our 2nd fresh cycle. We just did IVF again this past summer to try for a 2nd child but it sadly ended in a chemical. You could probably have success with IUI though. My RE has said you need at least 5 million for this to be successful. And, this is a way less invasive route. My cousin has endo and was successful with an IUI.
Trying the first time and through the 2nd, my dh tried many things like herbal supplements, cutting out caffeine, eating more protein, even trying acupuncture and nothing has raised his count. In fact, most recently, his count was down to 1 million but that was enough to do IVF anyway. I have heard of other success stories from men who have tried some of the above mentioned and they did have higher counts. So, I guess you never know. Oh, BTW, the life cycle of the sperm is about 70 days, so you wouldn't really see a difference until that much time has passed.