Blocking enzymes in dormant hair follicles may promote hair growth

In new research with mice, a combination of two drugs was used to block a group of enzymes in hair follicles and restored what researchers call "rapid and robust hair growth."

The two FDA-approved drugs -- ruxolitinib, used to treat blood diseases, and tofacitinib, for rheumatoid arthritis -- inhibit the Janus kinase, or JAK, family of enzymes.
While the researchers have said the finding is not a cure for male pattern baldness, they acknowledge it has some potential to get there.

"There aren't many compounds that can push hair follicles into their growth cycle so quickly," said Dr. Angela Christiano, a researcher at Columbia University Medical Center, in a press release. "Some topical agents induce tufts of hair here and there after a few weeks, but very few compounds have this potent an effect so quickly."

While studying treatment options for alopecia areata, a form of hairloss caused by an autoimmune attack on hair follicles, the researchers found the two drugs stopped the autoimmune attack and restored hair growth to some patients.

During work with mice during that study, they found that applying the drugs on the skin caused more hair to grow than when the drugs were given to rodents systemically.

In the new study, the researchers found the two drugs woke follicles up by blocking enzymes that caused them to stop growing hair. While the drug combination has not been tried in humans, human hair follicles grown in a dish and grafted onto the mice grew longer than the mice's own hair.

"What we've found is promising, though we haven't yet shown it's a cure for pattern baldness," Christiano said. "More work needs to be done to test if JAK inhibitors can induce hair growth in humans using formulations specially made for the scalp."