Especially if you have white hair , this is the natural solution.You need only tea water.
Take 2 spoon of tea powder in a bowl of water and boil it.wash your hair with this water and don't use shampoo.
Boil 2 tablespoons of black tea and 1 teaspoon of salt in water for 2 minutes and remove from flame. Let it cool and strain the liquid. Wash your hair with this liquid and let it dry, don’t rinse with shampoo.
Repeat it 2 to 3 times per week for best results.