Biologists at L'Oreal's research laboratories in Paris have spent the past three years studying eyelashes and comparing them to hairs elsewhere on the body.

Eyelashes grow for only three months before they fall, compared to the human head hair which grows up to three years.

Laboratory studies carried out by the researchers found that the hairs could be made to grow longer if the growing time was increased and thereby increasing the number of eyelashes on the eyelid making it to look bushier.

Dr Patricia Pineau, scientific director at L'oreal, said: "Modern mascaras create the illusion of longer eyelashes. When women take their make-up off, their lashes are still the same length.

"Eyelashes are similar to other hair in many ways, but they have two key differences that we can exploit.

"The first is the speed of growth, which is much faster in eyelashes while the second is the amount of hair growing at any one time. In head hair, 70 to 80 per cent of the hairs are growing at any one time while in eyelashes only about 15 per cent are growing.

"It was clear by increasing the duration of the growing phase the eyelashes would grow longer while postponing the start of the resting phase, when the lashes fall out, means there are more lashes on the eyelid fringe."

Dr Pineau and her colleagues found that a combination of citric acid, an amino acid known as arginine, and extracts from a Mexican plant known as Centella asiatica had the best effects.

The treatment is applied to the roots of the eyelashes as part of a white gel that is used each night for three months.

"Even we were surprised by the difference," said Dr Pineau. "Most of the women, about 80 per cent, have asked to keep using the serum."

L'oreal, said they hoped to market their product as a cosmetic that would be available over the counter.

Professor Valerie Randall, a researcher in hair growth at Bradford University, said: " This sounds like an interesting piece of research".

"Until recently eyelashes have not studied that closely as there didn't seem to be much that could be done with them other than putting on mascara, but the idea of promoting eyelash growth has now produced a great deal of interest in this area."