Treatment with baricitinib, an arthritis drug already approved for medical use in the United States and in the European Union, was found to be effective against baldness in a Phase III trial. The results, which were published in a peer-reviewed journal, could help millions around the world regain their lost hair.

Alopecia areata, also known as spot baldness, affects roughly 1 in 50 people — estimates put the number of cases at 6.8 million in the U.S. and 147 million people worldwide. The condition most commonly manifests itself on the scalp, but it can appear on other parts of the head and the body as well.

The causes and mechanisms behind the condition are not entirely clear, but alopecia areata is thought to be caused by the immune system attacking hair follicles. Although it’s not a life-threatening condition, it can be quite problematic and can cause substantial psychological harm.

“Alopecia areata is a crazy journey, marked by chaos, confusion, and profound sadness for many who suffer from it,” said Dr. Brett King, an associate professor of dermatology at the Yale School of Medicine and lead author of the new study, published March 26 in the New England Journal of Medicine. “It will be incredible to have a medicine to help people emerge on the other side, normalcy restored, recognizable again to themselves and those around them.”

Finding ways to treat this type of baldness would understandably be a big deal for many people around the world, so King and colleagues conducted two randomized trials involving adults with severe alopecia areata — at least half of them had lost all scalp hair.

For 36 weeks, participants were given either 4 milligrams of baricitinib (a drug used for arthritis), 2 milligrams of baricitinib, or a placebo. The trial was also double-blinded, meaning neither the researchers nor the participants knew who was in which group, to avoid any form of external influence.

Participants in the higher dose of baricitinib group had the most impressive results, regrowing much of their lost hair, but even the group in the lower dosage exhibited significant hair regrowth.

“This is so exciting because the data clearly show how effective baricitinib is,” King said. “These large, controlled trials tell us that we can alleviate some of the suffering from this awful disease.”

The trial used a common percentage tool for alopecia studies called Severity of Alopecia Tool (SALT) to evaluate how effective the drug is. SALT goes from 0 (no hair loss) to 100 (complete scalp hair loss). All participants had a score of at least 50 at the start of the study (they had lost at least half of their scalp hair), but by the end of the trial, around 1 in 3 participants in a high dose group had a score of 20 or less — meaning a large part of their hair grew back. Some 20% of the participants in the smaller group also had similar evolution.

But it gets even better. The drug administration was stopped after 36 weeks, but patient monitoring continued — and by 52 weeks, the majority of participants in the higher dose group had over 90% scalp coverage. In other words, within a year, the majority of patients suffering from severe alopecia areata had returned to almost complete hair coverage.

Now, researchers want to ensure the long-term effectiveness and safety of baricitinib, but there shouldn’t be any major roadblocks as 4 mg per day is also a dosage that has already been deemed safe for arthritis. If all goes well, the next step would be to start seeking approval for the drug; the FDA has already designated baricitinib as a “breakthrough therapy” for alopecia after previous study results, which means the review process should go faster than normal.

It seems a cure for this type of baldness may be just around the corner.

“This is so exciting, because the data clearly show how effective baricitinib is,” King said. “These large, controlled trials tell us that we can alleviate some of the suffering from this awful disease.”

The research was published in The New England Journal of Medicine.