Researchers have developed a baseball cap that drops the scalp – and can reverse male balding.
Experts first created a wireless patch that can stimulate the scalp with electrical pulses to encourage hair growth.
0.4-inch-thick plastic patches contain layers of various charged materials that produce electricity when they come into contact and are separated again.
It is a phenomenon called triboelectric effect and can result in faster hair growth than being connected to a machine for several hours a day. The team, from the University of Wisconsin-Madison, tested it on the backs of shaved lab trays and found that when they moved it caused the flexible patch to bend and stretch.
They found that this movement activated triboelectric effect and noted faster growth than in rats given minoxidil cream ̵
Next, the team, led by Xudong Wang, tested the patch on mice that were hairless due to a genetic deficiency.
They found that after nine days, 2 mm of fur had grown on the skin under the patch compared with 0.8 inches of long hair that had grown on skin treated with minoxidil.
The density of the hair was also three times greater
Wang also tested the patch on his dad, which has gone cold in recent years.
"It helped him grow many new hairs after a month," he told New Scientist.
His team has now designed a baseball cap that is cashier. It's the whole scalp of triboelectric materials.
Wang seeks approval to test it in men in a clinical trial.
He says that it should not be uncomfortable to wear because it produces very gentle electrical pulses.
However, the hat only works in men who are currently losing their hair or have recently become cold, as the skin loses its ability to generate new hair follicles after many years of baldness, he added.
It is also unlikely that it works even when men sleep because they do not produce so many movements to drive the device.
"Small head movements during normal daily activity should be sufficient to operate the unit," he added.
Earlier we reported on a breakthrough treatment from a team of researchers who say they have used stem cells to develop a way to do "unlimited" hair.
In pioneering experiments, human cells were inoculated on mouse cells and attached to small "scaffolds" to help them grow hetero.  They were then placed under the skin and came through it.
The team is now working on tests on humans.
About four in ten British sufferers suffer from some form of baldness.