TEHRAN (Tasnim) – 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 Daily Mail reported.

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.

Engineer Dr Xudong Wang and his colleagues created the patch, but electric pulse treatment has been studied - and used - for years.

According to The 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.'

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'.

The patch was attached to the backs of rats who had been shaved in the laboratory, in one study published in the journal ASC Nano.

Hair grew more rapidly than in other patches of skin which scientists had applied a standard balding treatment, minoxidil lotion, or placebo.

In rats with no hair due to a genetic deficiency, the patch caused 2mm of hair growth underneath the patch, compared to 1mm from minoxidil.

The hair density was also three times thicker for the patch-treated areas than those treated with minoxidil or placebo.

The researchers studied the skin of the mice under a microscope to examine what biological mechanisms were at play.

They found the release of natural chemicals that encourage hair to grow, such as keratinocyte growth factor and vascular endothelial growth factor.

Because hairless mice are considered a good reflection of balding men, Dr Wang is confident it will work in men, too.

But there isn't much promise for those who have been balding for many years - the patch may only work in men who have recently lost hair.

This is because the device reactivates follicles that are dormant instead of creating new ones.

Dr Wang thinks that wearing it for a few hours per day should be sufficient to get results but it won't work while sleeping.

He said: 'I think this will be a very practical solution to hair regeneration.'

Hair loss affects an estimated 25 per cent of men by the time they reach 25 years of age.

The most common treatment men and women use is minoxidil, which can come as a lotion or foam that stops and even reverses hereditary hair loss.

But it is rarely available on the NHS and may not work for everyone - even after trying for months on end - and has side effects such as headaches and low blood pressure.

Another popular treatment, finasteride, can be used by men on prescription only.

It works by decreasing the amount of the male sex hormone dihydrotestosterone (DHT) produced by the body, which can cause symptoms such as loss of sex drive and ejaculation difficulties.