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



A question that often crops up from our customers is to do with the strength or the ‘weight’ of hair colour; how long does hair colour last? How permanent is permanent hair dye? What’s the difference between semi permanent hair colour and permanent hair colour? And how long does semi permanent hair dye last?

We’re here to make the world of hair colour a simpler, supportive and feel-good place - so here’s the breakdown to these commonly asked questions. Let’s start with the heaviest weighing hair colour and work our way up. 

How long does Permanent hair colour last?

This one pretty much does what it says on the tin. This is designed to permanently change the colour of hair, without the hair colour washing out. At Josh Wood Colour, we have permanent hair colour on its own, with a Shade Shot to customise the tone, or the customer favourite, award-winning Miracle System: permanent colour, Shade Shot, and the Miracle Shot for that extra boost of condition and shine. 


A box of brown hair dye and a tube of chestnut brunette shade shot and miracle shot - Josh Wood Hair Colour Expert


When mixed with a developer, permanent hair dye opens the cuticles that comprise the surface of the hair shaft and delivers colour deep inside. For the Miracle System, this also means that the nutrients from the Miracle Shot also get deep into the hair. The cuticle then reseals, preventing the hair colour (and condition from the Miracle Shot!) from escaping. 




Often, permanent colour is the one that has that ‘hair dye’ smell, because it contains some harsher chemicals like ammonia or PPD, but ours doesn’t. We don’t use ammonia, which is why our permanent hair colour smells great.  

Permanent hair colour can be used to lighten or ‘lift’ the hair to make it brighter, if it contains enough peroxide. However, whilst ours might lift very slightly, it’s not designed for this, as we always recommend a salon visit for any clients looking for more of a transformative hair colour. 

The best bit? Permanent hair colour is the A* product for grey coverage. If you really don’t want any visible greys, or any peeping through, permanent colour is the best option. Our Miracle System offers 100% grey coverage which conditions as it colours, made in a selection of natural colours perfectly designed for you. 

What does Demi permanent hair colour mean?

Demi is, as you might expect, a mid-way point between permanent and semi permanent hair colour. It also usually involves a developer, and can last around 20 washes. Demi permanent hair dye is formulated to sit closer to the surface of hair, without penetrating as far down as permanent colour. For colour results, demi permanent hair colour is best used to darken or adjust the tone of hair. For grey coverage, the results give more of a blend rather than reliable coverage, so if you want proper grey coverage, opt for permanent hair dye

How long does Semi permanent hair dye last ?

At JWC, we love a semi-permanent colour for refreshing our hair colour, or trying something new without the commitment of permanent hair colour. Semi-permanent hair colour doesn’t contain ammonia or use a developer, and is designed only to deposit colour on the surface of the hair - a little like staining rather than transforming. Our range of Gloss and Glaze are fantastic semi permanent colours, which act like toners and, like our permanent colour, actually improve hair’s condition while colouring. Semi permanent hair colour usually lasts around 3-6 washes, so is great for trying something out or giving hair a pick-me-up. Our semi permanent Gloss, for example, is designed to adjust hair tone for 3-6 washes: try Icy Blonde Gloss as a corrective, conditioning hair toner to remove brassiness in blondes, or increase the richness and warmth of brunette hair with our Chestnut Brunette Gloss


Five tubes of hair gloss on a pink and purple background - Josh Wood Hair Colour Expert



Our Hair Glaze collection is also a semi-permanent hair colour, but in three beautiful pastel colours: Pink Quartz, Blue Reef and Peach Blush. These work on light hair and last 3-5 washes for the ideal, low commitment, bright summer hair colour. 


Three tubes of hair gloss on a colourful background - Josh Wood Hair Colour Expert

Temporary hair colour

Temporary hair colour is not designed to transform hair colour. Think of it like makeup for your hair, as it lasts up until your next wash. We love temporary hair colours as a quick fix for any grey hairs peeking through. Our range of Root Touch Up products, such as the Blending Brush or Airbrush Root Spray, provide temporary grey coverage that’s perfect for on-the-go or using in between permanent hair colour applications. 


A group of root touch up products on a colourful background - Josh Wood Hair Colour Expert



Remember, how long a hair colour lasts depends on the porosity, age, and density of the hair, so there’s not really one rule for everyone. What’s more, shampoos that contain sulphates will make colour fade faster, so if you’re looking to extend the life of your hair colour, opt for a sulphate free shampoo, like our Miracle Shampoo

As you can see, there’s a range of tools in our kit, so whatever your hair needs, we’ve got you covered. Have questions or need some advice? Speak to one of our friendly Client Delight team, or book a free 1:1 virtual hair colour consultation with one of our expert colourists.

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