The absolute best way to get a full head of hair growing again once you have developed bald spots is to get a hair implant surgery.  This method works great.  A cosmetic surgeon who speciallizes in hair restoration can offer you a hair transplant procedure that will take your own growing hair from the back of your head and transplant it to the bald area.  Within a 6 month time frame you should be seeing good hair growth results.  The new hair follicles are usually stressed for a while and it takes some time to get then growing but when they do your hair looks great.

One thing to consider is how much for hair implants.  This is where a lot of people get cold feet.  This procedure is not cheap and you can easily spend several thousand dollars.  But let me ask you something.   How much money will you spend on hair growth products over the next twenty years.  It probably would be as much as one hair restoration surgery.