Semi-permanent hair color is a type of hair dye that adds color to the hair without the use of harsh chemicals like ammonia. It typically lasts for about 4 to 12 washes, depending on the hair type and the product used. This makes it a popular choice for those looking to experiment with color without a long-term commitment. Unlike permanent hair color, which penetrates the hair shaft, semi-permanent color coats the outer layer of the hair. It gradually fades over time, allowing for a more natural transition back to the original hair color. Many people use semi-permanent color to enhance their natural shade or to cover gray hair.