I would recommend Mintop solution USP 2%. I used it. Its very effective. My doctor suggested this to me.
Another things are use Emblic Myrobalam or amla(Indian Gooseberry). You can get its fruit or powder form. Soak about a handful of dry amla in a cup of cold water. Leave the dried fruit or powder in water overnight and the next morning strain the water and extract the soft pulps of the fruits. Apply the fine paste on your hair and scalp uniformly. Leave it 30 minutes,then rinse off it with tepid water without using shampoo or any other cleansing product. Its natural remedy, mostly people in India believe its make hairs black. I have seen the results. Its makes hair shine. It suits, its natural with no harm.