Scientists in the US have synthesised a range of hair dyes, from blonde to black, using enzymes to catalyse synthetic melanin.
Melanin – a natural pigment that gives skin, hair and eyes a dark colour – is in every type of organism, making it a readily available and versatile material.
Researchers combined enzymes from mushrooms – which are rich with melanin – with an amino acid to mimic the melanin production in the body.
Synthesised melanin is less toxic than chemicals currently used to strip hair of its pigments before recolouring, which can cause skin irritation.
It could also provide an alternative for people with an allergy to hair dye who still want to be able to touch up their roots.
Researchers said they can achieve an arrange of colours by changing the concentration of melanin
‘From a biomedical perspective, there’s a huge market of people with a hair dye allergy,’ said Nathan Gianneschi at Northwestern University in Illinois.
‘Our first thought was it would be great to have a solution to help those people.’
In the typical process of colouring hair at the salon, stylists use bleach to strip melanin from hair, then add ammonia and dye to open and penetrate the hair cuticles.
Replacing melanin instead of removing it as a way of depositing colour on the surface of hair could create a more sustainable way to create lasting colour.
In humans, melanin acts as a defence mechanism against UV-ray sun damage, which is why people from hotter climates tend to have darker skin.
‘In humans, it’s in the back of our eye to help with vision, it’s in our skin to help with protecting skin cells from UV damage,’ said Gianneschi.
‘But birds also use it as a spectacular colour display – peacock feathers are made of melanin entirely.’
As well as being a milder process than traditional dye, coating hair in synthetic melanin also has the potential to protect hair from sun damage, which can cause whitening.
Researchers said they can achieve an array of colours, from light to dark by changing the concentration of their synthetic melanin.
The product would be in the form of a dye and would be applied in a similar way to usual hair colour, as a paste from a bottle.
Preliminary studies have also revealed potential for the coloured melanin layer to persist through several washes.
In the typical process of colouring hair, stylists use bleach to strip melanin from hair, then add ammonia and dye to open and penetrate the hair cuticles for permanent colour
‘The dyeing process is similar from a stylist’s point of view, but these conditions are milder, so they take a little longer,’ said lead study author Claudia Battistella.
‘Though it could be combined with a base, it’s not necessary to use one, and there is no need for chemical pigments.’
And because we already have melanin in our bodies, researchers think it is unlikely people would have an allergic reactions to it.
Traditional hair dye, on the other hand, is estimated to cause allergies and skin irritation in an estimated 1 per cent of humans.
Repeated use of some dyes has been linked to cancer – last year, researchers found women who regularly used permanent hair dye over eight years were 9 per cent more likely to develop breast cancer, compared to those who hadn’t.
Studies have indicated that people who dye their hair regularly may have a higher risk of cancer
And those who had a chemical hair straitening treatment every five to eight weeks had a 30 per cent higher risk.
The researchers warn chemicals are able to get into the skin through the scalp and fumes may also be inhaled while applying the dye.
Given the industry’s desire to move away from carcinogens and other toxic chemicals, synthetic melanin should be able to break through the regulatory industry, the experts believe.
They now aim to find a commercial partner willing to develop the dye on a larger scale and bring it to shops worldwide.
The research has been published in the journal Chemistry of Materials.