Permanent hair color changes your natural pigment for good. Semi permanent hair color coats each strand and fades away over time. That one fact explains most of what you need to know about these two products.

Ever stood in the hair color aisle and not known which box to pick up?  You are not alone. Semi permanent and permanent hair color solve different problems. If you make a wrong choice, you will end up being disappointed. 

This guide covers how each type works. You will learn which one covers grey hair. You will learn how long each one lasts. You will also learn how long to leave semi permanent dye in, whether you can mix it with permanent color, and how it behaves on relaxed or bleached hair.

Semi Permanent vs Permanent Hair Color

Permanent hair color opens the hair cuticle. It puts pigment deep inside the hair. That is why it does not wash out. Semi permanent hair color has no ammonia. It only coats the outside of the strand. That is why it fades.

Think of permanent color as a renovation. It changes the hair itself. That change stays until new hair grows in. Semi permanent color works more like a stain. It sits on top. It adds tone and shine. Then it fades away.

Do you want full grey coverage or a big color change? Permanent is usually the better choice. Do you want to test a new shade or skip harsh chemicals? Semi permanent color usually fits better.

What Is Permanent Hair Color?

Permanent hair color is a dye mixed with a developer. It opens the hair cuticle. It locks new pigment inside the hair. It stays there until you cut it or dye over it.

Permanent formulas use ammonia to lift the cuticle. They use peroxide to activate the color once it is inside the hair. Once the cuticle closes, the dye cannot rinse out. That is why this type is called permanent. According to the FDA’s own guidance on hair dyes, this basic chemistry is confirmed and outlines how these color additives are regulated in the United States.

This type of color can lighten hair. It can darken hair. It can shift hair to a new tone. It is also the only type that covers 100 percent of grey hair. That is why most colorists use it when a client wants zero visible grey.

Who permanent color is for. Permanent color suits anyone planning a big change, like going from brunette to blonde. It also suits anyone who wants full grey coverage. You should be comfortable with root touch ups every six to eight weeks.

How Long Does Permanent Hair Color Last?

Permanent hair color lasts until it grows out or gets cut. It does not fade like other types. A trip back for root touch ups is usually needed every six to eight weeks.

The color itself never fades. What changes is your regrowth. New hair grows in at your natural shade, creating a visible line at the roots. Scalp hair grows about half an inch per month on average. So faster growth or a big color contrast means you will notice that line sooner.

What Is Semi Permanent Hair Color?

Semi permanent hair color has no ammonia. It sits on the surface of the hair instead of going inside. It fades with each shampoo instead of growing out.

There is no developer in this formula. So semi permanent color cannot lighten hair. It cannot lift your natural pigment. It only adds a layer of tone on top of your current color. This is why the same shade looks different on light hair and dark hair. Your starting color matters.

Semi permanent color is popular for glosses and toners. It works well for fun colors like pink or blue. You get the fun look without a long commitment. It is also gentler on your hair, since it skips the chemicals that open the cuticle.

Who semi permanent color is for. Semi permanent color works best if you want a low commitment change. It is great for fixing brassy or dull hair. It also suits people with sensitive scalps who want to avoid ammonia.

How Long Does Semi Permanent Hair Color Last?

Semi permanent hair color usually lasts between 4 and 12 shampoos, fading out faster than demi or permanent formulas because it is made of smaller color molecules that only partially penetrate the hair shaft, instead of settling deep within it, according to hair dye classification research from the National Institutes of Health. The exact number of washes it lasts depends on your hair type, porosity, and aftercare.

Washing with hot water, using sulfate based shampoo, and reaching for heat tools often make color fade sooner.  Bleached or lightened hair is more porous, so it grabs color fast but also lets it go faster. Cool water, sulfate free shampoo, and a color depositing conditioner all help color last longer.

Want your color to last longer? Wash with cool water. Choose a sulfate free shampoo. Space out your wash days. A color depositing conditioner can also help keep the tone fresh between washes.

Where Demi Permanent Fits In

Demi permanent hair color sits between semi and permanent. It uses a small amount of developer. It lasts longer than semi permanent color. But it still washes out instead of growing out.

This middle option goes a little into the hair shaft. That lets it last around 20 to 28 shampoos, a range most professional colorists use as a general guideline for demi permanent color as of 2026. It is typically mixed with a lower strength developer than permanent color, around 3 percent peroxide compared to about 6 percent for permanent, which lets color deposit without fully lifting the hair’s natural pigment. That is much longer than a typical gloss. But it does not last as long as full permanent color.

Demi permanent color cannot lighten hair. It lacks the strong peroxide that permanent formulas use. Instead, it works well for deepening tone. It blends early greys. It refreshes hair that looks dull.

Who demi permanent color is for. Demi permanent color suits anyone with light to moderate grey. It works for anyone who wants darker hair without a full commitment. It also suits anyone moving away from permanent color who still wants some lasting power.

Comparison Table: Temporary, Semi, Demi, and Permanent

Placing all four color types next to one another makes the decision simpler. This table lays out the details that matter most.

Feature	Temporary	Semi Permanent	Demi Permanent	Permanent
Contains ammonia	No	No	No	Yes
Needs a developer	No	No	Low volume	Yes
Can lighten hair	No	No	No	Yes
Grey coverage	None	Blends only	Partial	Full
Average longevity	One wash	4 to 12 washes	20 to 28 washes	6 to 8 weeks, then regrowth
Typical processing time	Instant	20 to 35 minutes	20 to 30 minutes	30 to 45 minutes
Damage level	None	Minimal	Low	Higher

As the table shows, lasting power and grey coverage both go up as you move toward permanent color. Gentleness on your hair moves the other way.

Semi Permanent vs Permanent Hair Color For Grey Coverage

Permanent hair color is the only type that gives full grey coverage. It fully coats the inside of the hair. Semi permanent color can soften grey. It cannot hide it completely.

Do you have less than 25 percent grey hair? Semi permanent color can blend it in nicely, especially on lighter shades. Once your grey passes that point, most colorists recommend permanent color instead. It gives more even results.

This is a common letdown for first time colorists. Someone with a lot of grey uses a semi permanent gloss. They expect full coverage. Then the grey peeks back through after just one or two washes.

Demi vs Semi Permanent Hair Color For Grey Hair

Demi permanent color blends grey better than semi permanent color. It also lasts much longer. Still, it does not give the full coverage that permanent color gives.

Semi permanent color usually lasts 4 to 12 washes. Demi permanent color can last 20 to 28 washes, a range commonly used across professional hair color brands as of 2026. If you are just starting to notice a few greys, demi often feels like the natural next step.

Many colorists suggest starting with demi permanent color if you have under 25 percent grey. It gives more blending power without a full commitment. As your grey grows, permanent color usually becomes the better long term choice.

How Long To Leave Semi Permanent Hair Dye In Before Rinsing

Most semi permanent dyes need 20 to 35 minutes to fully develop. The exact time depends on the brand and product strength. Always check your product’s instructions first.

Should you leave it in for 2 hours? That is usually not needed. The color will not turn much more vibrant, since it has already bonded within the normal time window. Longer wait times also raise the risk of uneven color or scalp staining.

Leaving it in overnight is not a good idea either. The color often turns out darker than planned. Long contact can also dry out your hair or irritate your skin. If this happens by accident, do not worry. Wash with a clarifying shampoo. The extra color will fade with normal washing.

Once you mix hair dye, it stays usable for about an hour. After that, it starts to lose strength. Never save mixed permanent or demi permanent color for later use. The chemical process has already started and cannot be paused.

Can You Mix Permanent And Semi Permanent Hair Color?

Yes, you can use both together. But never mix them in the same bowl. Many colorists use both in one appointment. They just apply each one to different parts of the hair.

One popular method uses permanent color on the roots. This gives full grey coverage and a fresh base. Then a semi permanent gloss goes on the mid lengths and ends. This adds shine. It evens out tone. It refreshes older color without over processing it.

Are you growing out permanent color? A semi permanent gloss can help. It softens the line between your natural regrowth and your existing color. It will not remove that line completely. But it makes the contrast less obvious until your next color service.

Semi Permanent Color And Relaxed Hair

You can use semi permanent color on relaxed hair. But relaxed hair is more porous. It absorbs color faster than untreated hair. So use extra care. Color often develops faster and can turn out darker than expected.

Most stylists suggest waiting one to two weeks after a relaxer before adding any color. This gives your hair and scalp time to recover from the relaxer.

A strand test matters here. Put a small amount of color on a hidden section of relaxed hair first. Check the result after the normal processing time. This helps you avoid a surprise shade or extra damage on your whole head.

Relaxed hair can also get dry and break easily. Try a deep conditioning treatment before you color. Healthy, well moisturized hair holds color more evenly. It also looks shinier once the color sets in.

Will Semi Permanent Color Wash Out Of Bleached Hair Faster?

Yes, Semi permanent color usually fades faster on bleached hair. Bleaching raises the hair cuticle. That raises porosity too. The same porosity that grabs color fast also lets color slip out fast.

On bleached or lightened hair, a bold semi permanent shade might last two to four weeks with good care. The same product could fade within days on hair with lower porosity. This is why colorists often pre lighten hair to a pale base before applying bold semi permanent shades.

Want your color to last longer on bleached hair? Wash less often. Use cool water. Apply a bond building treatment often to keep your hair as healthy as you can.

Which Option Is Right For Me?

Choose permanent hair color if you want full grey coverage. Choose it if you plan to lighten or darken your hair a lot. You should also be fine with root touch ups every six to eight weeks. It gives the most lasting, dramatic change.

Choose semi permanent hair color if you want a low commitment option. Choose it if your hair is damaged or relaxed and needs gentle care. It also works well if you just want to refresh your tone between salon visits. It is a safer starting point if you are unsure about a new color.

Ask yourself three quick questions. How much grey are you covering? How much damage can your hair handle right now? How often are you willing to touch up your color? Your honest answers will point you to the right choice almost every time.

Faqs

How can I make demi permanent color fade faster?

Demi permanent color will fade after approximately 20-28 washings, even if you don’t enjoy the results. A clarifying shampoo, colour remover or colour correcting treatment will help to make the process quicker. Warm water also helps, because it softens the cuticles and allows the color to release more quickly, but hot water may dry hair and make it more brittle.

How long should I wait between color applications?

Most colorists recommend waiting four to six weeks between semi permanent or demi permanent color sessions. This gap gives your hair time to recover and helps prevent the dryness or damage that comes from over processing. If your hair feels brittle or dry after coloring, waiting even longer before the next application is worth it.

Can I use Kool Aid as a semi permanent hair color?

Kool Aid is not a true semi permanent hair color, despite the popular belief. Its dye does not actually bond to the hair shaft the way real semi permanent formulas do. It can tint very light or bleached hair for a short while, but the color rinses out almost immediately with plain water.

Is demi permanent hair color less damaging than semi permanent hair color?

Semi permanent color is generally the gentler option, since it sits entirely on the surface without opening the cuticle at all. Demi permanent color is still low damage, but it does raise the cuticle slightly to deposit pigment, which means a touch more processing than semi permanent formulas require.

Can demi permanent color refresh faded highlights or balayage?

Yes, demi permanent color works well for refreshing faded highlights or balayage, since it adds tone and richness without lifting or lightening the hair further. Many colorists use it between salon visits to brighten dull ends, correct brassiness, and extend the life of a lightening service with no added damage.

Can semi permanent color fix brassy or yellow toned hair?

Yes, semi permanent color is a common fix for brassy or yellow toned hair, especially on blondes. A purple or blue toned formula neutralizes unwanted warmth using basic color theory, calming yellow or orange tones. Since it only coats the surface, this correction naturally fades within a few weeks.

What is hair glazing, and is it the same as semi permanent color?

Hair glazing is a clear or lightly tinted treatment applied over your existing color to boost shine and seal the cuticle. It is not identical to standard semi permanent color, since a glaze focuses on a glassy finish rather than changing your tone, though many glazes are built on a semi permanent base.

Conclusion

Choosing between semi permanent and permanent hair color comes down to three things. How much grey you need to cover. How much of a commitment you want to make. How gentle your hair needs the process to be.

Permanent color gives full grey coverage and lasting change. Semi permanent color gives you a gentler, low commitment way to try something new. Demi permanent color sits in between. It offers a longer lasting blend without the full chemical process.

Whatever you pick, knowing how semi permanent and permanent hair color work will help you get the result you want. Want to learn more? Check out our other guides on grey coverage, at home color tips, and how to protect color treated hair.