What is a hair toner? Why toning is the most important part of your hair colouring process

If you’re wondering what a hair toner is, you’re not alone. When salon chain Taylor Taylor London asked their clients having a colour service if they knew about toners, 86 per cent were in the dark.

However, ask a hair colourist (celebrity hair colourist Zoe Adams, in this case) and they'll tell you “toning is the most important part of the colour process". And not only for blondes—as is commonly assumed.

With many myths surrounding the topic of toners, we asked the experts to explain it all.

What is a hair toner–and who is it for?

A hair toner is a product used to achieve and help maintain your desired colour, both professionally and at home.

“Hair toner is every colourist’s best friend,” explains Samantha Cusick, founder of salon Samantha Cusick London. “It works magic on coloured and bleached hair and helps us to correct the tone and personalise your colour.”

Typically, toner is used to neutralise unwanted warm undertones, she adds, “as brassiness on blondes—which can also occur on redheads and brunettes—is something we want to avoid”.

For toner to work, hair needs to be pre-lightened or coloured first. "Bleaching is a tool that we use to take colour, or pigment, out of the hair,” explains Adams. She expands, "The professional term is a 'pre-lightener'. During this process, you are pulling the pigment from the hair, stripping away the colour but not adding any colour." Your final colour then comes from the toning process.

“You can go anywhere with a toner," she reveals. "On blondes, cooler toner makes the colour more silvery, and warmer toner makes it more coppery.”

But Cusick confirms that all coloured hair benefits from a toner—not only light hair. “It can be used on all shades of hair to remove brassy tones as well as add depth and shine.”

Should I be using a hair toner for shine as well as colour?

Indeed, "toners don't just add colour to the hair,” says Adams. “As well as toning the hair it can restore coloured hair that’s started to fade, colour correct any accidental streaks or smudges that might occur and add a gorgeous gloss,” Cusick adds.

Gloss is something you can achieve from a clear toner, too. Adams explains that “acid-based toners can add shine to natural hair and won't affect the colour”. By reflecting the light, this gives hair a super glossy, varnish-like effect which colourists call 'glossing'.

For this effect achieved in salons, ask for a Redken Shades EQ hair gloss. After an initial consultation, your hairstylist will create a custom hair gloss for you which works in 15 minutes. It boosts the condition of the hair while imparting shine. “It’s like lip gloss for your hair,” says Cusick. Alternatively, at home try the Glaze Super Color Conditioning Gloss Sheer Glow, a semi-permanent hair gloss that works like a deep conditioning treatment leaving a mirror shine.

What are the types of hair toner?

As mentioned above, there are professional in-salon hair toners and glosses, such as the Redken Shades EQ, while toners for at-home use can take many different forms.

Depending on whether you primarily want to enhance or tweak your colour there are various options, from colour correcting shampoos to pigment depositing masks, glazes, and glosses.

If you’re looking to maintain your salon-fresh tones, “the first step in helping your colour last longer is to use a shampoo that’s especially formulated to prevent brassiness in coloured hair,” Cusick explains. She recommends the Redken Blondage and Brownlights ranges. “Use once a week to help keep your hair looking salon-fresh for longer.”

Adams concurs. "Try to choose an at-home shampoo and conditioner or mask that has toner incorporated within the product. This will refresh your hair each time you wash it and help prolong the colour. However, it is important to avoid over-washing hair—ideally, wash it no more than twice a week to best maintain your colour."

How long does toner last?

No toner lasts—which is why coloured hair changes tone, or appears to fade.

"Depending on your hair type, toner can last between two-to-six weeks,” explains Adams. This will also rest on the product you used.

“The general rule of thumb is that previously coloured hair which is more porous will hold colour for less time than natural or 'virgin' hair, which can hold colour for up to six weeks," reveals Adams.

A professional salon-use toner is more pigmented meaning the results will last longer than an at-home toning product, like a shampoo or mask.

This piece originally appeared in Harper's Bazaar UK