In a discovery that could brighten up the lives of millions, scientists have created a drug that restores white hair to its natural colour.
They hope the drug, converted into a shampoo, could eventually be used as an alternative to dyes to hide greying locks.
The drug was found to trigger the production of pigmentation in hair samples tested in a lab.
These pigments restored the hair to its original colour, from the white or grey it had become.
This took place no matter what the hair colour was to begin with.
The drug, known only as K(D)PT, increased pigmentation when it was applied to hairs gleaned from women undergoing facelifts.
However, it was effective only when the strands had been pre-treated to mimic the damage found in conditions that cause hair loss, including some forms of alopecia.
In such conditions, hair that grows back is often white.
Researcher Dr Ralf Paus, of the Manchester University and the University of Lubeck in Germany, said the drug ‘deserved to be explored as an innovative new anti-greying agent’.
Writing in the British Journal of Dermatology, he added: ‘Specifically, topical application of K(D)PT may become exploitable for the treatment of post-inflammatory hair whitening that is often seen during the recovery phase of alopecia areata.’
Nina Goad, of the British Association for Dermatologists, described the study as ‘an important step’.
She added: ‘It is important to note this is laboratory research and not yet ready for use on patients.
‘However, while the research is still at a very early stage, these findings could potentially pave the way for new therapies that restore colour to white hair.’
The researchers believe there is also ‘a reasonable possibility’ that hair turned grey by ageing would also respond.
The preliminary nature of the work means it is not possible to say if the drug would fully restore hair to its natural colour, although this could well be the case.
It is likely the treatment, which would have to be reapplied regularly, would work for men and women.
The synthetic hormone in the drug could only be used on lab hair samples. It is not yet ready to be applied directly to a patient’s head.