People with grey hair could one day pop a pill if they want to restore their hair to its natural colour.

Scientists at French cosmetics giant L'Oreal have identified a pair of genes that may play a key role in turning hair grey.

They say these genes may determine how long many of the cells that give hair its natural colour live.

They believe that by targeting these genes they may be able to help these cells live longer, preventing grey hair.

Hair turns grey when the cells that give it's colour die.

However, the French scientists have found that some of these cells, which are called melanocytes, survive even when somebody's hair has turned grey.

"We discovered that the hair whitening process was linked to the progressive decrease in the absolute number of melanocytes," said lead researcher Dr Bruno Bernard.

"We believe that some of the genes we are studying right now might be involved or linked to this progressive decrease.

Possible treatments

Dr Bernard said while much more work is needed the findings could lead to new treatments.

"If we can block this progressive decrease, we could block the whitening process," he told BBC News Online.

"This is a big step forward in terms of identifying possible targets.

"We could be talking about a pill or we could be talking about a topical treatment."

Dr Bernard said full details of the work would be published in a scientific journal next month.

Desmond Tobin, a reader in cell biology at the University of Bradford who has carried out research in this area, said he would await the paper with interest.

"I will be interested to see what genes they are talking about. If it's true, it is quite a story," he told BBC News Online.

But he suggested that turning the discovery into a new treatment could prove challenging.

"We would need to find a long-lasting solution because hair grows in cycles. Restoring the pigment would not be a permanent thing."

The findings were released ahead of a new exhibition on hair at the Natural History Museum in London.

The exhibition, which runs until 26 September, explores the science of hair, showing how it can reveal a wealth of information about a person's diet, health and ethnicity.