The only clinically proven ingredient in shampoos that combats hair loss is 1%-2% Ketoconazole, which has anti-fungal properties and increases blood circulation on the scalp. Look up Nizoral or Regenepure DR shampoo. Everything else like saw palmetto extract, emu oil, Vitamin B3, caffeine, hops extract and whatever else homeopathic treatments are out there might be good for general hair and follicle health, but as far as I'm aware of there are no peer-reviewed studies on their efficacy that show statically significant results.
What you should do is use a Ketoconazole shampoo 2-3 times a week (it's rather harsh so don't use it everyday), make sure you leave the shampoo on your scalp for a few minutes before rinsing. For the other days of the week use a mild shampoo/conditioner that makes your hair healthier, such as one containing saw palmetto or biotin.