Sustainable hair dye made from blackcurrant waste

Chemists have developed an all-natural hair dye made from blackcurrant skins which are normally thrown away

The global hair dye industry is worth around USD 10 billion a year. More than 5,000 ingredients are used to make hair dyes, and studies show that some of these may promote cancer or cause allergic reactions. Moreover around 95 percent of all dyes end up washed down the drain. These substances eventually end up in rivers and streams, where they may pose an environmental hazard. Now, two researchers at the University of Leeds have created a natural, sustainable hair dye made from blackcurrant skins.

Colour chemist Dr Richard Blackburn and organic chemist Professor Chris Rayner developed a new technology to extract anthocyanin pigment from blackcurrant fruit waste. Anthocyanins are the pigments that give many berries, fruits and flowers their colour. They are non-toxic, water-soluble and are already widely used as food colourants. The researchers chose to work with anthocyanins because they also bind strongly with proteins, such as hair. Around 90 percent of British blackcurrants are used to make Ribena, a blackcurrant-flavoured cordial.

During Ribena production, the skins are discarded. These skins have very high concentrations of anthocyanins, and provide a sustainable supply of raw material. The colour is extracted using a water-based process and filtration – no toxic or hazardous chemicals are used. The resulting dyes can produce intense reds, purples and blues that hold for at least 12 washes.

The researchers are commercialising their dyeing technology through a University of Leeds spinout company called Keracol Limited, under the brand Dr Craft. They have also developed a natural purple shampoo, which counteracts brassy tones in blonde and grey hair. The blackcurrant-based dyes and shampoo should be on sale this summer. More and more cosmetics innovations focus on sustainability and the use of natural ingredients. These include lip balms made from fruit and a startup that sells pre-owned makeup. Will Dr. Craft help to reduce the use of chemical dyes?