Here's why:
* Tanning affects the skin: Tanning is a result of increased melanin production in the skin, caused by exposure to UV rays. It doesn't affect the hair follicles or the pigment in your hair (melanin).
* Hair pigment is different: The melanin that gives your hair its color is different from the melanin in your skin. It's embedded in the hair shaft and not affected by sun exposure.
While tanning might make your hair appear lighter against a darker skin tone, it's simply a contrast effect and not an actual change in hair color.
If you're looking to lighten your hair, you'll need to use hair color products or consider other methods like bleaching or highlights.