Can you mix permanent and semi permanent hair color? [Expert advice]

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If you’ve ever wanted to know if you can mix permanent and semi-permanent hair dye, you’re not alone. The truth is, you can mix them all you like but it won’t result in anything that looks good! In this blog post we highlight why using both formulations together is not the cleverest thing to do and what you should be doing instead!

Let’s go!

Can you mix permanent and semi permanent hair color?

Mixing permanent and semi-permanent hair dye is not recommended as the two types of dyes have different chemical ingredients and purpose.

Mixing permanent hair dye with semi-permanent dye may cause an uneven result due to their incompatible formulas – so one type will cancel out or completely cover the other. This could lead to an icky, ‘muddy’ look in which neither shade stands out properly or an unexpected patchy result that you are not happy with!

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

First thing’s first, the main difference between permanent and semi-permanent hair color is that permanent dyes penetrate into the hair shaft while semi-permanent dyes simply coat the outside of each strand.

Permanent hair color is in its name—it’s here to stay.

This type of hair dye is ideal if you’re looking for a base hue or an all-over color that won’t budge anytime soon. It also can be used if you want to lighten your natural hue or go much darker than your original shade.

Depending on the product, it can last up to eight weeks before needing touch ups. With permanent color, there are more options available for achieving certain looks such as adding lighter highlights or going for cool-toned blondes, so if you have something specific in mind this may be the route for you. 

Semi-permanent dyes are great if you don’t want anything too dramatic that lasts forever.

They’re also perfect for adding subtle dimension with lowlights or covering up any pesky grays without completely changing your overall look.

These dyes typically last up to four weeks, depending on the product used, and wash away slowly over time so there’s no need for harsh root touch ups every few weeks (yay!).

Plus they come in all sorts of fun colors like pastel pinks and purples so they’re perfect if you want something daring but don’t feel like committing fully just yet! 

Watch and learn: What’s the Difference Between Permanent, Demi & Semi-Permanent Hair Colors?

So where does demi-permanent fit in? Here’s a great video that talks you through the differences between Semi-permanent vs demi-permanent vs permanent hair dye!

Is it safe to mix a semi permanent hair dye with a permanent hair dye?

It’s totally safe to mix a semi permanent hair dye with a permanent hair dye. But just because it won’t cause any harm doesn’t mean you should do it!

The chemicals in the two dyes are designed to produce very distinct results, combining them simply won’t do anything at all; they’ll just… cancel each other out.

So while no harm will come to your luscious locks, if you’re expecting something magical when these two combine, don’t hold your breath!

Can you put semi-permanent hair dye over permanent?

If you’re thinking of refreshing your color, using semi-permanent dye over permanent hair color is generally a safe option—just be sure to choose one that is the same shade or darker than your current hue.

Keep in mind, however, that it won’t lighten your hair color.

It’s a great way to perk up one-tone hair but we’d leave a few days in between the two dye jobs to avoid over-processing and damaging your hair.

Can you mix permanent and semi permanent hair color infographic

Can you mix permanent hair dye and developer?

Mixing permanent hair dye and developer together is the way to go to achieve your desired color.

The developer helps to open up the cuticles of your strands so that the dye can penetrate and deposit its pigment.

Each type of hair dye will require a certain strength or volume developer, which will be detailed on the instructions—so be sure to read them before you get mixing! We also have a great guide on mixing hair dye and developer if you’re looking for different strengths and tips.

What happens if you mix semi permanent hair color with developer?

Mixing semi-permanent hair color with developer won’t give you the same results as a permanent dye—the molecules in the semi-permanent color are too large to penetrate through the cuticles of your strands.

Instead, what will happen is that you’ll end up with an unappealing blotchy, uneven coverage and a patchy look in which neither shade stands out properly or an unexpected result that you are not happy with!

We recommend sticking to either permanent or semi-permanent dyes and avoiding mixing them altogether if possible.

Parting words

So there you have it—you can mix permanent and semi-permanent hair color but depending on your desired results we’d recommend sticking to one or the other for best results!

Just make sure to do your research and read the instructions to ensure you get the look you want!

Good luck!

This article was written by:

  • Nicola Freeman, Creative Director & Content Lead
    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!