I went through a rough period awhile ago, and lost ALOT of hair. I haven't had much luck with Nioxin type shampoos, and really don't like thickening one's either. I find them drying.
I like Pureologly shampoo/cond. They have a hydrating conditioner with peppermint in it. I love it. I massage my scalp well when shampooing too. I brush my hair often through the day as that helps remove air pollutants/ dust, etc. and it's stimulating on the scalp. I started taking 5000 mgs of Biotin, and My hair is soooo much fuller...yep, my scrunchy doesn't slip out LOL. I still have fine hair (always have) but I've got LOTs of it now! I hope this helps you!!