I'm not bald -- it's just that my hair's asleep
It could be good news for anyone starting to thin out on top. Researchers have discovered that rather than losing their hair altogether, balding people are suffering from "sleeping" hair follicles.
Trichologists have found that hair follicles on the scalp can become trapped in a resting state where they do not grow new hair, leading to thinning.
They claim to have identified a way of waking the follicles up, to help restore a fuller head of hair to people who are going bald.
The treatment may not be able to delay the balding process forever, as eventually the follicles lose the ability to make new hair, but it may stave off the wigs, comb-overs or hair transplants used by some to cover up baldness.
Bruno Bernard, head of hair biology at L'Oreal in Paris, which carried out the research, announced that the company was developing a treatment that can be applied to the scalp in a shampoo or cream to help encourage hair growth.
"Hair follicles exist in two stable states -- either an active state or a dormant state," he said.
"From time to time, they will jump from one state to another. Some of the follicles are just resting in the dormant state and are waiting for the right signal to make new hair.
"They are in a latency period. If you can reduce this latency period, you will have more hair."
Up to half of all men suffer from androgenic alopecia, which is the most common cause of hair loss and thinning in humans. Many women also suffer from a degree of excessive hair loss.
Typically, hair strands grow continually for a period of up to four years before the follicles switch to a dormant state and the strand of hair falls out.
During this dormant period, stem cells in the skin begin the processes needed to grow new hair. In balding people, this process can stall and new hair does not form.
The scientists found two reservoirs of stem cells that were responsible for creating new hair, one near the skin's surface and one deeper in the layers of the skin.
The bottom reservoir of stem cells, called CD34+ cells, are in an environment that is low in oxygen, called hypoxia, which helps to keep the stem cells in a healthy condition.
Mr Bernard, who presented the findings at the European Hair Research society in Barcelona last week, said that in people who were going bald, the levels of oxygen around these stem cells had changed, meaning they worked less efficiently and so prevented the creation of new hair.
He said his team had found molecules that mimicked the effects of hypoxia, which could be used to "push the empty hair follicles to make new hair".