Demi? Semi? Er, what’s the difference…?

Hairdressers’ lingo can be confusing at times – so we quizzed some top colourists to decode the demi from the semi

There are plenty of industry-specific terms which are bandied about a salon to cause confusion. You might think you know your ombré from your balayage, but what about your demi from your semi-permanent colour options? Is there a difference? Is it just marketing bumf?

Turns out yes, there is a difference! Knowing your options means you can be more specific with your hairdresser (and earn brownie points for knowing your stuff, naturally), which means you’ve got a much better chance of ending up with a colour result you actually want. Win-win!

“Colour is super complex and can be a very difficult world to understand,” agrees Gareth Williams, creative ambassador and colour lead at Headmasters. “I would always advise to visit an expert colourist as it’s a skilled job and will take a professional to get it right.”

Gareth laid out the major differences between the two options for us:

Semi-Permanent Colour

“This is a colour that will sit on the outside of the cuticle (your hair’s first layer). If you have no colour on your hair and you use a semi-permanent colour, you would usually expect it to last for up to 10 washes. It’s great for adding shine and conditioning the hair, and it can also blend white hair.

If you already have coloured hair and you add a semi-permanent colour on top, the colour molecules will attach themselves to what is already present in the hair and therefore give you a more permanent result.”

Demi-Permanent Colour

“Demi-permanent colour will sit on the outside and the inside of hair cuticle. This will last longer, approximately 20 to 30 washes if your hair has no colour.”

Both demi and semi-permanent colour options are ideal for low maintenance colour updates, trying out a new look and really enhancing the condition of your hair.

“The homecare hair dye market like to use the terms ‘semi’ and ‘demi’ permanent and this is very different to what colourists themselves would say. It can be very confusing!” says Lloyd Court, colour director at Skyler London. “Demi-permanent colour is usually a great option for first time colouring because it will grow out softer. The demi-permanent colour usually fades over time, leaving a less visible regrowth line than permanent colour while still offering a big range. They’re great if you want to go darker, if you’re looking to cover some greys, or if you don’t want to commit to a permanent colour.”

Rob Czapka, founder of RCNQ in Manchester, suggests switching things out to a demi-permanent option occasionally if you’ve noticed a real impact on the quality of your hair from repeated permanent colour. Due to the size of the colour molecules it can help to give your hair a breather, without you having to give up colour altogether.

Meanwhile, semi-permanent options are perfect for more fleeting flights of colour fancy. “Semi-permanent colours do not contain bleach or ammonia and are fantastic for deepening colours, changing tone or adding more vibrancy,” Sophie Gibson at Hooker & Young explains. “These are ideal if you want to try colour in the salon but are a bit nervous. Semis stain the hair as opposed to dying it and they don’t last as long, so are great for adding tone without longevity.”

So there you have it! Whether you’re looking to add a hint of colour to your balayage, or testing out whether you suit a darker hue, knowing the difference between your semi and demi-permanent can help you achieve your colour goals.