Does hair color in bottle if not open go bad?

Unopened hair dye can last for several years if stored properly, typically retaining its effectiveness until the expiration date indicated on the packaging. However, over time, the chemical components may degrade, which can affect the dye's performance. It's best to check the expiration date and store the product in a cool, dry place away from direct sunlight. If you're unsure about an old bottle, it's safer to replace it rather than risk subpar results.