There was a study in the University of Pennsylvania that has found that another way to stimulate hair growth, at least in mice, is to wound the skin.
“The researchers made relatively large wounds on the backs of adult mice, and found that if a wound reached a certain size new hairs formed at its center, with the skin undergoing changes mimicking stages of embryonic hair-follicle development.”
Now, I don’t want to start a debate over animal testing and cruelty, so please let’s not bring up this detail, but the premise is that creating a large wound on a bald spot will spark stem cells to create hair-follicle cells.
The downside, aside from having rather unpleasant head trauma in treatment, is the hair grew back without pigmentation.
The upside, aside from laughing at somebody who has jet black hair everywhere but the top of his head, is that they are now investigating ways to simulate a wound in the head without actually wounding the skin.
Source: http://www.cnn.com/2007/TECH/science/05/17/baldness.study.reut/index.html
