What’s the Difference Between Semi-Permanent and Permanent Hair Dye?

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What’s the difference between semi-permanent and permanent hair dye?

When it comes to dyeing our hair at home, we’re faced with many choices that can confuse the best of us. 

Hair dye for roots, hair dye for greys, hair dye for the latest trends, there’s plenty to think about.

Perhaps the biggest decision to make is whether we want to use semi-permanent or permanent dye and what is the difference between them anyway? Let’s find out!

Choosing one can be overwhelming.

No matter what style or color you’re looking for, it’s hard to know what to choose and why.

We’ll help you make the right decision by explaining the difference between these two types of hair dyes, as well as their pros and cons.

This way you’ll find out which one is right for your needs! Plus we’ve got all of our top tips on how to get great results at home using both types of dyes.

What’s the Difference Between Semi-Permanent and Permanent Hair Dye?

Difference between semi-permanent and permanent hair dye infographic: 
Aspect	Semi-Permanent Hair Dye	Permanent Hair Dye
Tonal Change	Slight tonal change	More coverage and significant change
Coverage of Greys	Can cover greys	Covers greys
Coating or Absorption	Covers and coats your hair	Absorbs into your hair
Hydrogen Peroxide	Contains no hydrogen peroxide	Contains hydrogen peroxide
Duration	Lasts about 10-12 washes	Lasts 12-24 washes


What are semi-permanent hair dyes?

Semi-permanent hair color is the one you use when you want to experiment with color.

They typically wash out in between 10-14 washes, so you can change up your color as often as your heart desires.

How does semi-permanent hair dye work?

Semi-permanent hair dye contains tiny color molecules that enter the hair’s cuticle, or outer layer.

So they add color without dramatically changing the structure of your hair like permanent color does.

They don’t interact with your natural pigments. And since the molecules are small, they eventually wash out and fade until your hair goes back to how it was before treatment. 

How long does semi-permanent hair dye last?

This formula enhances your natural color so you won’t get roots growing out like you will with permanent dyes.

But it’s also not as effective at covering greys and the effects won’t last as long – around 10-12 washes.

The thing about semi-permanent is that it won’t lighten your hair color because it contains no ammonia or peroxide.

So if your hair is darker, it’ll need to be stripped first (by your hairdresser).

Because it’s more temporary, you can have LOADS of fun experimenting with colors and the ones available tend to be as bold as they come!

Liven up your locks by trying colored hair streaks, vibrant highlights or even half and half style hair!

Pros

  • Experimentation: Ideal for trying out new colors and styles without committing to a long-term change.
  • Temporary Results: Washes out in about 10-12 washes, allowing for frequent color changes and versatility.
  • Gentle on Hair: Contains no ammonia or peroxide, so it doesn’t dramatically alter the hair’s structure or damage it.
  • Enhances Natural Color: Adds depth and richness to your existing hair color without creating obvious roots.
  • Vibrant Colors: Offers bold and vibrant shades for creative and eye-catching hairstyles.
  • Low Commitment: Great for those who want to refresh their look temporarily or for special occasions.
  • User-Friendly Application: Often available in easy-to-use formulas for at-home application.
  • Color Correction: Can be used to correct minor color imperfections or refresh fading permanent color.

Cons

  • Short Duration: Fades relatively quickly, requiring frequent reapplication for those who desire long-lasting color.
  • Limited Grey Coverage: Not as effective at covering grey or white hair compared to permanent dyes.
  • No Lightening Effect: Cannot lighten hair color, making it unsuitable for drastic color changes on darker hair.
  • Color Variation: The final color outcome may vary depending on the starting hair color and texture.
  • Limited Color Range: Some shades may not be available in semi-permanent formulas, limiting color choices.
  • More Frequent Application: Requires more maintenance and frequent touch-ups for consistent color.
  • Staining Concerns: May stain clothing, towels, or pillowcases during the first few washes after application.
  • Chemical Sensitivities: Some individuals may still experience mild sensitivities to ingredients in the dye.

Best for: experimenting with different colors and styles.


What are permanent hair dyes? 

Permanent hair dye is what you need for great grey coverage and strong, long-lasting color.

How does permanent hair dye work?

This dye doesn’t just rinse across your hair and stain it like semi-permanent hair dye.

It actually has to break through a couple of barriers in your hair to set…well…permanently.

Permanent changes the actual makeup of your hair.

It does this by the use of peroxide which opens the cuticle of the hair shaft allowing the color to really penetrate to the core.

Tiny molecules enter all the way into the cortex, where they react and expand to a size that cannot be washed out.

How long does permanent hair dye last?

This means your hair color actually has to grow out over time which is why you end up with roots which you typically need to get touched up every 4-6 weeks.

Permanent color also can’t lighten your color. COLOR NEVER LIGHTENS COLOR!

You need to get your hair lightened by a professional for that.

But if you want to go a new shade or a darker shade, permanent will definitely give you the best results for longer.

This also makes these dyes more damaging to your hair. The chemicals used are stronger and the mixture usually has to be left on for a longer period of time. 

So only use it if your greys are really stubborn or your color change needs to be dramatically different.

Pros

  • Great Grey Coverage: Ideal for effectively covering grey or white hair, providing consistent and reliable results.
  • Long-Lasting Color: Offers a durable and permanent color change that doesn’t wash out with each shampoo.
  • Penetrates to the Core: By using peroxide to open the hair cuticle, the color penetrates deep into the hair’s cortex for lasting results.
  • Versatile Color Options: Allows for a wide range of color choices, including going darker or trying a completely different shade.
  • Minimal Fading: Provides color that doesn’t fade significantly, reducing the need for frequent touch-ups.
  • Root Touch-ups: Requires touch-ups every 4-6 weeks due to hair growth, ensuring continuous color consistency.
  • Color Depth: The color change is not superficial, leading to a more profound and rich color outcome.

Cons

  • Hair Damage: The chemicals used in permanent hair dye are stronger and can cause more damage to the hair over time.
  • Longer Processing Time: The dye mixture usually needs to be left on the hair for a longer duration, which can be time-consuming.
  • Cannot Lighten Hair: Permanent color cannot lighten the hair’s existing color; lightening requires professional bleaching.
  • Commitment: The color change is permanent, making it less suitable for those who like frequent changes or indecisive about color choices.
  • Potential Dramatic Changes: The permanent nature of the dye makes it best suited for those seeking a significant and lasting color transformation.

Best for: Gray coverage and long-lasting, strong color


Semi-permanent vs permanent hair dye – Which one is right for me?

With so many colors and types of hair dyes available, it can be hard to know which one is right for you. Let’s explore the differences between these two types of hair dyes and help you figure out which one is best for you.

Hair Type & Texture

The first thing to consider is your hair type and texture.

If you have fine or damaged hair, semi-permanent hair dye may be the best option for you. Semi-permanent hair dyes are gentler on your hair and won’t cause as much damage.

If you have thick or coarse hair, permanent hair dye may be a better option, as it can penetrate the hair shaft better and provide more long-lasting results.

Hair Color

Next, consider the hair color you want to achieve.

If you’re going for a dramatic change, permanent hair dye may be the way to go. Permanent hair dyes can lighten your hair up to three shades, while semi-permanent dyes can only darken your hair or add a slight tint.

If you’re looking for a subtle change or just want to enhance your natural color, semi-permanent hair dye may be your best option.

Lifestyle

Your lifestyle is another important thing to consider.

If you have a busy schedule and don’t have much time for touch-ups, you may want to opt for permanent hair dye. Permanent hair dye can last up to six to eight weeks, while semi-permanent hair dye typically only lasts up to four weeks.

If you like to switch up your color often and can make time for regular touch-ups, semi-permanent hair dye may be the better option for you.

Strand Test

Lastly, don’t forget to do a strand test before choosing a hair dye.

A strand test will help you determine how the dye will look on your hair and whether you’re allergic to any of the ingredients. T

o do a strand test, apply the hair dye to a small section of hair and wait the recommended amount of time before washing it out.

If you’re happy with the results and don’t experience any allergic reactions, you can move forward with dyeing your entire head of hair!

Frequently Asked Questions

How does hair dye work?

Let’s look at what dye actually DOES to your hair.

Here’s the sciencey bit – hair color contains tiny color molecules that barge their way into your hair’s cuticle, or outer layer, and burrow deeper into your hair’s cortex.

How deep they go and how much they stick is what makes them different.

Here’s a great film that shows you what happens to your hair when you dye it and how hair dye works.

YouTube video

Is semi or permanent hair dye better?

The best way to decide what type of hair dye is right for you and your lifestyle, is by looking at the pros and cons of each option.

Semi-permanent dyes are a great choice if you want a temporary change or have an active schedule that might require frequent touch-ups.

Permanent dyes leave no room for error but can last up to 8 weeks with proper care.

If you’re pregnant, it’s important to be careful with permanent hair dye as chemicals like ammonia can be harmful during pregnancy (though semi-permanent dyes may still be okay).

And you can’t mix semi-permanent and permanent hair dye together. They both have different formulas so it’s like mixing oil and water. Nothing will happen and you may end up with patchy, uneven color.

Does semi-permanent hair dye wash out completely?

Semi-permanent hair dye is a great option for those who want a subtle color change that fades over time.

This type of dye doesn’t contain ammonia or peroxide, which are harsh chemicals that can damage your hair.

One of the biggest advantages of using semi-permanent hair color is that it allows you to experiment with different shades without making a long-term commitment.

The color will gradually fade away after a few washes, so you can switch to a new hue as often as you like.

However, because semi-permanent dye is designed to gradually wash away, it’s not the best option if you want a bright color that lasts for several months.

Does semi-permanent hair dye last longer?

How long semi-permanent hair dye lasts depends on several factors, such as how often you wash your hair, the strength of the dye, and the porosity of your hair.

If you use a high-quality semi-permanent dye and take care of your hair properly, you can expect the color to last for up to six weeks.

However, keep in mind that because the color gradually fades over time, it might not be as vibrant as it was when you first applied it.

If you want a color that lasts longer, you might want to consider permanent hair dye.

Semi-permanent dye is, however, a great choice for people who want to try out a new color without making a long-term commitment.

What are the disadvantages of semi-permanent hair dye?

One of the downsides of using semi-permanent hair dye is that it can be difficult to get an exact shade.

The color might not be as vibrant or long-lasting as you would like, or it might fade unevenly.

If you have dark hair, it might be difficult to achieve a light shade with semi-permanent dye because it doesn’t contain bleach.

Finally, if you have damaged or porous hair, the color might not take evenly, and you might need to apply multiple coats to get the desired shade.

Parting words.

Ultimately though, there isn’t one perfect hair dye – we just need to find something that will work for us!

The true answer lies in the condition of your hair right now and how much coverage you really need. You can always ask the advice of a professional. 

We recommend getting a free consultation at your local salon to find out a) what color they would recommend for your skin tone and b) whether you should be using permanent or semi-permanent.

Loading yourself with as much advice as you can will mean you choose the right dye for you and will get the results if you choose to go for it and dye your hair at home.

With both options, you want to take care not to quicken the pace of fading. Follow our advice in How to look after colored hair and keep it luscious for longer and thank us later.

Authors

  • Nicola Freeman, Creative Director & Content Lead

    With over two decades of passionate hair dyeing experience, I've experimented with nearly every shade imaginable. My journey began long before blogging; as an award-winning copywriter in London and New York, I shaped narratives for iconic brands. However, when friends sought advice during lockdown for at-home hair dyeing, I realized my true calling. Beyond being your hair color expert, I'm a mom of two girls, wife to artist Tony, and an avid soccer player!

  • Enza Piazza, Hair Stylist & Color Consultant

    I’m Enza Piazza, your go-to hair stylist and color consultant with over 23 years of professional salon experience bringing vibrancy and life to hair of all hues. My Italian roots from sunny Sicily infuse passion into every snip and color, a passion that’s been recognized with top honor awards including bridal and party hair at the National Hairdressers Federation’s Championships. After training in Surrey, UK’s most prestigious salons including Head Master Academy, I embraced the entrepreneurial spirit and set up Enza Hair Styling, offering tailored hair care for 13 years, and treating each client like family. Away from the salon, I cherish moments as a proud Nonna to grandson Joseph and as a playful companion to my Jack Russell, Bo.