* Semi-permanent dyes deposit color on the hair shaft but don't penetrate the cortex like permanent dyes. This means they can't lighten or drastically change existing color.
* Permanent dyes contain ammonia and peroxide, which open the hair cuticle and allow the color to penetrate. This means the permanent color is already deeply embedded in your hair.
* Trying to apply a semi-permanent dye over permanent dye may result in:
* Uneven color: The semi-permanent dye may not be able to penetrate the already-colored hair evenly.
* A muddy or dull color: The semi-permanent dye might not be able to fully cover the permanent color, creating a less than desirable result.
* Color fading quickly: The semi-permanent dye will be more prone to fading since it's only deposited on the surface of the hair.
If you want to change your hair color:
* Consider using a permanent dye again: If you want a drastic color change, it's best to use a permanent dye. Be sure to consult with a professional stylist to determine the best approach for your specific hair needs.
* Use a color remover: If you want to remove the existing permanent color, you can use a color remover product. This will help to lighten the hair and allow you to then apply the desired color.
In summary, it's generally not recommended to put a semi-permanent hair dye over a permanent dye. You may end up with an uneven or undesirable color result. Always consult with a professional stylist for personalized advice and guidance on hair coloring.