Hippocrates recommended a blend of pigeon droppings, cumin, horseradish and beet-root, and the Ancient Egyptian remedy included toes of a dog and hoof of an ass.
Now the prospect of a baldness cure that actually works has moved closer after scientists proved for the first time that it is possible to create entirely new follicles from which hairs grow.
A groundbreaking experiment on mice has suggested that it should eventually be possible to reprogram the skin to sprout hair from scratch, to replace the lost locks of millions of men as well as women who suffer from alopecia.
Almost all men suffer from a degree of hair loss by the time they reach 60, and almost a third are appreciably bald by the age of 30. Although hair loss is usually less severe among women, and tends to occur later, it is often more distressing.
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The new results have astonished scientists, as it has long been assumed that hair follicles are formed only in embryos, and thus cannot be reactivated once lost.
Although drug treatments can sometimes slow or stop the advance of baldness and hair transplants can cover up the effects, there was little hope of a therapy to reverse hair loss.
The research changes the picture completely by proving in principle that new follicles, and hence new hair, can be generated from other cells in the skin of adults.
Scientists are now seeking ways of manipulating the genes responsible for follicle formation so that bald scalps can be “reseeded” with hair – and hair growth can be prevented where it is not wanted.
Insights from the research should also aid the development of new ways of healing wounds without scarring, and treatments for skin conditions such as acne.
“This is an extremely exciting discovery and shows promise for treatment of follicular disorders such as hair loss and unwanted excess hair,” said Vera Price, of Follica, a company that is developing the research commercially.
A drug that can do this, however, probably remains at least a decade away. The mice in the study grew new follicles only from skin where large wounds had been deliberately inflicted, which would not be appropriate for human cosmetic treatments.
There are also important differences in the way that human and mouse skin heals, which will have to be better understood if the process is to be exploited for therapy.
The inspiration for the research came from anecdotal reports of follicles forming spontaneously and sprouting hairs on skin where a wound had healed.
In the study, published in the journal Nature,a team from the University of Pennsylvania led by George Cotsarelis removed large patches of skin from the backs of mice and left them undressed to investigate the healing process. The scientists found that, as the wounds healed, the skin entered an “embryonic window of opportunity” during which a key gene called Wnt became active.
Wnt, which is known to be important to follicle formation, is usually operational only in embryos. The Wnt activity caused skin stem cells to migrate to the site of the injury, where hair follicles were regenerated.
The gene’s critical role was confirmed by two further experiments. By introducing extra Wnt proteins to the wound the scientists were able to double follicle growth to produce thicker fur. When Wnt was inhibited, the mice grew fewer hairs as their wounds healed.
This suggests that it could also be possible to regenerate hair by finding a way of reawakening Wnt in undamaged skin, raising the possibility of drugs for reversing baldness.
In a commentary for Nature, Cheng-Ming Chuong, of the University of Southern California, said: “These findings will undoubtedly inspire new thinking in the management of alopecia, in tissue engineering and in the regeneration of other organs.”
The regrowth effect had probably not been identified before in humans because wounds large enough to kick-start it tended to be treated with stitches or dressings, which appeared to inhibit the formation of new follicles, he said.
Dr Cotsarelis, also a co-founder of Follica, said: “We’ve found that we can influence wound healing with Wnts or other proteins that allow the skin to heal in a way that has less scarring and includes all the normal structures of skin, such as hair follicles and oil glands, rather than just a scar.”
British experts said they were encouraged by the research.