Hair-care professionals reveal what dyeing your hair actually does to your locks and what can be done to protect them.
The damage done
Dr Joe Cincotta, the executive vice president of product development for Color Wow, says, "When you expose hair to ammonia, hydrogen peroxide and high pH", which are often all present in hair dye, "you damage your hair's lipid layer. When this lubricating membrane is lost, your cuticle no longer lies flat, your hair looks dry, feels rough and is more susceptible to humidity, frizz and tangles." This explains why you often feel you have to sacrifice your hair's texture and volume for your dream colour.
"As you successively colour-treat your hair", Dr Cincotta continues, "the keratin – proteins in the cortex [internal structure of the hair] – are fragmented into smaller pieces. As a result, they gradually leach out of the hair every time your hair is wet." This is of particular concern because "as hair fibres lose protein, they lose mass and their structural integrity is degraded", resulting in your hair becoming really fine.
Dr Cincotta also emphasised that as a result of dyeing your hair, "the sulphur bonds [within the hair's cortex] that link the keratin proteins together break, causing irreversible damage." These sulphur bonds "are key to your hair's strength and elasticity and breaking them weakens the hair's internal structure. This makes your hair more prone to breakage and can cause serious hair damage."
Danielle Llewellyn, UK Hair Ambassador for eSalon, emphasises that "bleaching your hair can cause particular damage because the chemicals used in the process open the pores in your hair and bleach is so strong that it leaves the cuticle extremely porous". This results not only in weaker hair but also means that if you then apply colour to your hair "the dye will fade out very fast because the pores are enlarged."
In the salon
According to Nicola Clarke, the creative colour director for John Frieda and Color Wow, "there are lots of products you can use to ensure that your colour will always look its best whether you are super blonde or transitioning to a darker shade."
In John Frieda salons they use Olaplex, "which allows you to colour hair without damaging it, and to re-build hair strength."
Danielle Llewellyn also suggests that you should use "a high-quality dye that will prevent damage, rather than cause it". She would recommend eSalon's special dye formulas that are blended with conditioning elements, like vitamins E, B5 and aloe vera to help condition your hair so that it's actually healthier after the colour application than it was before.
"Should your hair need some extra TLC", says Christel Lundqvist, the founder and director of STIL Salon, "there are plenty of effective in-salon treatments that you can experience to strengthen your hair, most notably ones that contain keratin. At STIL, we offer the Hydrating Colour Boost Service, which infuses the hair with keratin to strengthen the hair's structure while gently boosting the hair's existing colour."
Clarke advises using a sulphate-free shampoo at home "to stop colour from fading and becoming brassy. It's free from silicones, conditioning and pearlising agents so it's the only shampoo that leaves your hair clean without leaving anything behind."
Llewellyn also believes that you should "alwayswash your hair with a shampoo and conditioner designed for colour-treated hair as colour-safe products are gentle and don't strip out moisture like sulphate-laden types do."
Cover up and take your time
It's also important, if you can bear it, to go as long as possible between trips to the salon.
She also emphasises that when changing colour you should "make time to do it slowly. Start by adding a few brighter flecks of colour around the face or ends to bump up the brightness and get you and your hair ready for the new colour. This will also have the added benefit of giving your hair glossy, shiny colour that accentuates your best features."
The same approach is favoured by Llewellyn who advises against "lightening hair by over one or two shades' and when possible suggests doing 'a roots-only application to avoid causing more damage to previously coloured sections".