Semi-permanent dye is a type of hair color that lasts longer than temporary dyes but does not provide the long-lasting effects of permanent dyes. Typically, it can last anywhere from a few washes to several weeks, depending on the hair type and the product used. Semi-permanent dyes do not contain harsh chemicals like ammonia, making them a gentler option for coloring hair. These dyes work by coating the hair shaft rather than penetrating it, which allows for easy application and removal. They are often used for enhancing natural color, adding shine, or experimenting with bold shades without a long-term commitment. Popular brands include Clairol, Manic Panic, and L'Oreal.