A semi-permanent hair dye can last for approximately six weeks. The semi-permanent hair dye will fade progressively and through exposure to air as well as shampooing.
A person choosing to semi-permanently dye his or her hair will need to re-dye it frequently. This is damaging to hair. However, semi-permanent hair dye provides a more natural color, although it cannot lighten a person's natural hair color due to its lack of bleach.
Another option is permanent hair dye. Permanent hair dyes use an oxidizer and ammonia in order to dye the hair, and do not need to be used as often because they are "permanent." However, permanent dye can be quite damaging to the hair so it is important to create a plan with a colorist before getting treatment.
Regardless of the type of dye that is used, it is important that the hair is properly cared for after treatment. Stylists and colorists recommend using a pre-shampoo deep conditioning treatment weekly after the treatment as well as three days before the dye treatment. This will help to keep hair moisturized and make it less likely to break. It is also recommended to use a smoothing finishing product to seal the cuticle of the hair keeping moisture from leaving after styling.