The belief is that something is inhibiting the follicle from growing a normal hair. One of those factors seems to be PGD2, which was found near stem cells in the follicle, which are important in hair growth, Cotsarelis explained.
Dr. Sanusi Umar, a dermatologist in Redondo Beach, Calif. and associate faculty at University of California, Los Angeles, said it's long been known that prostaglandins are involved with hair growth, while this study shows that the opposite may also be true.
For example, Latisse (bimatoprost ophthalmic solution) is a synthetic prostaglandin (mimicking PGF2) that encourages eyelash growth, while Rogaine (minoxidil) is thought to work by promoting the activity of another prostaglandin, PGE2, Umar noted.
"This study tells the other side of the story," he said.
Yet, Umar urged men not to toss out their Rogaine yet. "Yes, this may open another front from which hair loss may be treated. It is not likely to be the panacea, however," he added.
There are likely multiple prostaglandins involved with inhibiting or promoting hair growth, he pointed out. Steroids and nonsteroidal anti-inflammatory drugs also inhibit PGD2 "but have not been shown to consistently grow hair," Umar noted.
"It is more likely that a number of end factors contribute to hair loss with factors like PGD2 inhibiting hair growth and others such as PGE2 and PGF2 promoting it," he said. "PGD2 inhibition may emerge as part of a combined approach used in combination with agents that work via different mechanisms . . . as a more effective approach to hair loss treatment."
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