What baking soda does to gray hair is lighten the gray hair and remove impurities in the gray hair and improve hair texture.
Baking soda can lighten the gray hair and remove buildup of minerals which can dull, distort and darken the color of gray hair.
Using baking soda on gray hair can also improve the texture of your gray hair.
The use of baking soda on hair including gray hair can also exfoliate your scalp and promote the growth of healthy hair.
However you must use caution when using baking soda on your hair as it can dry out the hair and make it brittle as the baking soda can affect your hair's ability to retain moisture.
To use baking soda on your gray hair or other color of hair start by mixing the baking soda with water.
Mixing the baking soda with water before applying it to your hair reduces it's potentially damaging effects.
Then apply the baking soda and water mixture to wet or dry hair.
Scrub the baking soda and water mixture into your hair like you would with shampoo.
Then rinse your hair thoroughly with water to rinse out the baking soda.
After you rinse out the baking soda you should then apply some hair conditioner.
If you have dry hair you should use hair conditioner to help moisturize your scalp and hair.
You can also use apple cider vinegar and Kaolin clay on gray hair and it doesn't have the same risks of damaging hair like baking soda does.