White hair turns yellow when external factors build up on the hair, resulting in a yellow stain. External factors include cigarette smoke, air pollution, minerals found in tap water, chlorine from pools, hair products and some medications. Yellowing may also occur as a result of bleaching or sun exposure. Bleach and the sun remove color pigment. Even though it may not look like it, white hair possesses some color pigment. The sun and bleach remove blue-based color molecules, causing the yellow-based molecules to appear more prominently.
Shampoo your hair with a blue-based color enhancing shampoo. Condition your hair with a complementary blue-based conditioner. Leave the conditioner in the hair for three to five minutes.
Shampoo weekly with a deep clarifying shampoo. Follow up with the blue-based color enhancing conditioner.
Perform weekly clarifying treatments only if you see signs of yellowing. Discontinue treatments once the yellow stain is removed.
Use bottled water to shampoo your hair if you have hard water or well water. Install a water softener if you do not wish to shampoo your hair with bottled water.
Wear a cap or use an umbrella to shade your hair from the sun.
Avoid smoky environments, and shampoo your hair immediately after being in a smoky environment. Smoke outdoors if you are a smoker.