In a study published by researchers at Columbia University Medical Center, inhibiting a family of enzymes inside hair follicles that are suspended in a resting state can restore hair growth. The researched conducted experiments on mice using drugs that inhibit the Janus kinase, or JAK, family of enzymes which resulted in rapid hair growth. JAK inhibitors trigger the follicles’ normal reawakening process, the researchers found. Mice treated for five days with one of two JAK inhibitors sprouted new hair within 10 days, greatly accelerating the hair follicle growth phase. No hair grew on untreated control mice in the same time period.

The two FDA approved drugs are ruxolitinib and tofacitinib. Ruxolitinib is an approved treatment for blood diseases and tofacitinib is used to treat rheumatoid arthritis.

Scientist have said that while what they have found is promising, a lot more work needs to be done to test JAK inhibitors specifically for hair regrowth in humans.