Shampoo for Hair Loss

I used to have quite long hair past my shoulders and used to freak out whenever I saw the amount of hair loss I had. A friend recommended me Dove shampoo for hair loss which was said to reduce the amount of hair droppage. However, it did not do that much for my hair when I was using it and I still found lots of hair in the bathroom after my shower. I tried cutting my hair shorter as I suspected the length could be the problem but it has still been dropping quite a bit. Does anyone have a fool proof hair loss shampoo they can recommend? I don't really want to be balding before my time!