Demipermanent

Demipermanent, often written as demi-permanent or demi, refers to a category of hair color that sits between temporary and permanent formulations. It deposits color and adds tone to the hair without significantly lifting the base pigment, using low-strength developers or sometimes no developer at all.

Chemistry and how it works: Demi-permanent dyes use oxidative chemistry with small amounts of developer to activate pigment molecules that deposit onto the cortex and diffuse into the cuticle. The color molecules are designed to be durable but not as permanent as traditional permanent dyes, so they gradually fade with washing. Most formulations do not contain ammonia and are marketed as less damaging than permanent color. Because lifting of natural pigment is limited, gray coverage is typically lighter than with permanent color.

Uses and outcomes: This type of color is commonly used to refresh color between salon visits, correct brassiness, add cool or warm tones, and blend gray rather than fully cover it. It is suitable for subtle color changes and for those who want a reversible or low-commitment result. Demi-permanent color is not ideal for drastic shade changes or significant lift, such as going from dark to very light.

Longevity and maintenance: The color generally lasts about 12 to 28 shampoos, with fade occurring gradually and evenly. Longevity depends on hair porosity, washing frequency, and exposure to sun or chlorine. Since it does not lift existing color substantially, regrowth may be less noticeable than with permanent color, but gray regrowth can become apparent if substantial gray exists.

Safety and considerations: Patch testing is recommended to screen for allergies to dye ingredients. Results vary by starting color, porosity, and product formulation. Professional guidance is advised for best shade match and application, particularly when achieving precise tonal results.