A hat that zaps the scalp with a built-in patch that produces electricity on its own may combat male balding, scientists hope.
A trial of the device on the balding father of one of the researchers has proven it can work - helping him regrow hair within a month.
Other experiments on rats found it worker as effectively, if not better, than drugs used to treat hair loss. No side effects were seen.
The 1mm-wide patch sends electric pulses to the scalp when triggered by motion, promoting natural hair growth chemicals in the skin.
The University of Wisconsin researchers said the electric pulses are only gentle, and shouldn't be uncomfortable to put up with.
The team are now designing a baseball cap which contains a patch that encases the whole scalp in the aim of trialling it on more men.
The hat contains a built-in patch which sends electric pulses to the scalp when triggered by motion, promoting natural hair growth chemicals in the skin
A prototype of the patch was tested on the lead researchers father
Studies on rats found the patch worked significantly better than current lotions to treat hair loss
Engineer Dr Xudong Wang and his colleagues created the patch, but electric pulse treatment has been studied - and used - for years.
According to New Scientist, Dr Wang has tested the patch on his father, who has been balding for several years.
'It helped him to grow a lot of new hairs after one month,' he said.
'Small head movements during normal daily activity should be enough to power the device.'
Engineer Dr Xudong Wang at the University of Wisconsin said: 'Electric stimulations can help many different body functions.'
The gentle electric pulses penetrate the outerlayers of the skin, deep enough to stimulate the hair follicle but shallow enough to avoid damage to the deeper tissue.
There are clinical trials proving their efficacy to promote hair growth in dormant follicles.
Researchers in Canada in 1990 found a 66 per cent increase in hair count in men who received a form of electric pulses once a week for 36 weeks.
Mr Wang's study on rats suggests the electric current causes an increase in growth factors or 'proteins' necessary for hair to grow.
There are already treatments on the market that use electric pulses, but a patient needs to fit the criteria.
But it's not a very practical treatment at the moment, because patients may have to sit under wired up to a machine for several hours at a time.
The patch, made of a flexible piece of plastic, vibrates with electricity when it senses body movement.
Materials inside the plastic patch produce an electrical charge when they come into contact and rub together - known as the 'triboelectric effect'.sonos sonos One (Gen 2) - Voice Controlled Smart