Permanent vs Demi vs Semi-Permanent Hair Color

Permanent color lifts and deposits in one step and grows out instead of washing out. Demi-permanent deposits with little or no lift and fades over a few weeks. Semi-permanent is pre-made dye with no developer that stains the hair and rinses away a little with every shampoo. The rest of this guide is the detail behind those three sentences.

What each type does inside the hair

Permanent: lift and deposit at once

Permanent color is alkaline. An alkalizer, either ammonia or a substitute such as MEA, swells the cuticle so small dye precursors can move into the cortex. Developer then does two jobs at the same time. It breaks down natural melanin, which is lift, and it oxidizes the precursors so they link into larger color molecules that are too big to wash back out. That is why permanent color stays until it grows out or gets cut off. Tone can still fade, especially reds and coppers, but the depth holds.

Because it lifts, permanent color exposes underlying pigment. Take a natural level 5 up to a level 7 and you uncover orange and gold warmth that the formula has to control. That is the whole story behind why natural roots go brassy.

Demi-permanent: deposit with little or no lift

Demi is still oxidative color, so it mixes with a developer or activator, but the peroxide is low and most lines skip ammonia. The developed color molecules are smaller than permanent ones and sit closer to the surface, so they release slowly with each shampoo. Demi fades gradually and never leaves a hard regrowth line.

Demis come in two families, split by pH:

• Alkaline demi sits above pH 7. It opens the cuticle more, deposits richer and deeper color, handles more gray, and some lines give a small amount of lift.
• Acidic demi sits below pH 7. It keeps the cuticle tighter, adds shine and sheer tone, and does not lift. This is what the salon floor calls a gloss or toner.

Semi-permanent: direct dye, no developer

Semi-permanent color is already colored in the tube. There is no developer and no chemical reaction. The pre-formed dye settles on and just under the cuticle, then washes out bit by bit. Semi cannot lift, so it only shows on hair light enough for it to read. A bright pink on a level 5 brunette shows up as a faint stain at most.

Developer for each type

This is where students mix the categories up most often.

• Permanent: 10, 20, 30 or 40 volume, picked by how much lift you need. Color Fusion from Redken mixes 1:1 with Pro-Oxide Cream Developer. Redken lists 10 volume for up to 1 level of lift, 20 volume for up to 2 levels with standard gray coverage, 30 volume for up to 3 and 40 volume for 3 or more. Color Fusion Extra Lift shades mix 1:2 for up to 5 levels.
• Alkaline demi: low volume only. Shades ALK mixes 1 oz of color with 1.5 oz of Pro-Oxide Cream Developer 10 volume, and Redken limits it to that 10 volume.
• Acidic demi: a dedicated processing solution instead of a standard developer. Shades EQ mixes 1:1 with Shades EQ Processing Solution.
• Semi: nothing at all. Color Intensity Semi-Permanent from Joico goes on straight from the tube or intermixed, with no developer.

For the full breakdown of volumes and percentages, see developer volume explained.

Side-by-side comparison

Gray coverage, line by line

Gray hair has no natural pigment for the dye to blend with, so coverage depends on how much color gets inside and stays there.

• Color Fusion: Redken rates it for up to 75% gray and calls it ideal for clients with less than 50% gray. For heavier gray, Redken points to Cover Fusion, rated for up to 100%.
• Shades ALK: up to 75% gray with the N, NA, NCh, NB and GI families, and up to 50% with every other family. So 5NCh or 6NB is a coverage pick, while 6RV from the red violet family tops out at 50%.
• Shades EQ: blends gray and does not claim coverage. Redken's blending guide adds an NB shade to the target shade. For up to 25% gray, that is 1/2 oz of NB with 1 1/2 oz of the desired shade and 2 oz of processing solution, 15 minutes under a warm dryer. Standard processing on gray runs up to 40 minutes at room temperature.
• Semi: no coverage claim. Expect a see-through tint on white hair.

When to choose each

Virgin roots and regrowth: permanent

Reach for permanent when the gray needs real coverage. A client at a natural level 6 with about 30% gray who wants to stay a level 6 neutral takes 6N Color Fusion mixed 1:1 with 20 volume, processed 35 to 45 minutes with no heat. Keep permanent on the new growth. On virgin roots with no gray, a demi at the natural level is the safer default, as covered in why natural roots go brassy. Pulling it through previously colored ends every visit stacks pigment and leaves ends darker and duller than the root.

Faded mids and ends: demi

Refresh hair that is already colored with a demi instead of more permanent. Alkaline demi is the pick when ends have lost depth, or when you want one formula from root to ends with gray blending and no real lift. After that Color Fusion root, a demi at the same level, such as 6N in Shades ALK, brings the ends back without stacking. Redken notes that Shades ALK and Shades EQ can be used together in the same service or separately.

Gloss and toner: acidic demi

Acidic demi is for prelightened hair that needs tone and for any hair that just needs shine. Redken frames it this way: acidic demis excel at toning and shine, while Shades ALK brings depth and richness. Since acidic demi does not lift, it changes the tone sitting on a level, never the level itself. On blonde lifted to pale yellow, 09V cancels the yellow, while 09NB keeps more warmth for a softer blonde. Add 000 Crystal Clear to sheer out any shade. Shades EQ goes on dry hair for 20 minutes at room temperature, and Redken says underprocessing or applying on wet hair greatly reduces how long it lasts. For another alkaline and acidic pair from a different brand, read Matrix Super Sync vs Tonal Control.

Fashion colors: semi

Vivids and pastels belong to semi. The hair has to be lightened first, because semi only deposits. Joico's Color Intensity chart lists a prelighten level for each shade, from 7 to 10, so you know how light the base has to be before you apply. Ruby Red is a Bold shade, and Bold shades last up to 20+ shampoos. Rose Gold and Silver Ice are Power Pastels, which last up to 10. Metallics land in between at up to 15. When the client is ready for a change, Color Intensity Eraser removes the direct dye in 30 minutes or less.

Reading the type before the code

Check the product type at the top of the chart before you read a single shade. The same level and tone can live in three lines with three different chemistries. Redken prints 6N in both Color Fusion and Shades ALK, and the Shades EQ version carries a leading zero as 06N. The level means the same thing in each, as covered in the hair color levels student guide. What changes is lift, gray coverage and how long it lasts. If chart layouts still slow you down, start with how to read a hair color chart.

Formula Finder builds formulas from real shade codes in your brand, starting from the client's inspo pic.