Scientists say they have moved a step closer to banishing bald spots and reversing receding hairlines after human hair was grown in the laboratory.
A joint UK and US team was able to create new hairs from tissue samples.
Far more research is needed, but the group said its technique had the "potential to transform" the treatment of hair loss.
The study results were published in the journal Proceedings of the National Academy of Sciences.
There are baldness therapies including drugs to slow the loss of hairs, and transplants, which move hair from the back of the head to cover bald spots.
The scientists at the University of Durham, in the UK, and Columbia University Medical Centre, in the US, were trying to actually grow new hairs.
Their plan was to start with material taken from the base of a hair and use it to grow many new hairs.
But human hair has been tricky to grow despite successes in animal studies.
Whenever human tissue was taken from the dermal papillae, the cells which form the base of each hair follicle, the cells would transform into skin instead of growing new hairs.
However, the group found that by clumping the cells together in "3D spheroids" they would keep their hairy identity.
Tissue was taken from seven people and grown in 3D spheroids. These were then transplanted into human skin which had been grafted on to the backs of mice.