Demi-permanent hair color falls between permanent and semi-permanent hair color. Demi-permanent color is less damaging to hair than permanent. "Demi" colors last up to 24 washings, which is longer than "semi" colors; however, because it contains no ammonia, demi-permanent color is not able to lighten hair.
Demi-permanent hair color intensifies shades of natural or color-treated hair. The demi color fades gradually, so new hair growth is not glaringly apparent. Gray hair responds well to demi-permanent color. If a slightly lighter shade than natural is chosen, the gray spots become highlights, and the natural color is not affected. Demi-permanent color is sometimes in conjunction with permanent. While the permanent color is applied to new growth at the roots, the "demi" refreshes the color of the ends without damage.