Cool How Long Does Unopened Hair Dye Last References. Web l’oréal paris says that their l’oréal preference hair dyes will expire after 3 years. Read the ingredients to ensure the dye.

Web “however, the shelf life of hair color is typically three years from production if unopened and kept away from heat and humidity in perfect conditions.” according to the l’oréal labs,. As hair dye stays on your. Web l’oréal paris says that their l’oréal preference hair dyes will expire after 3 years.