A University of Melbourne-led study had found two new drugs allowed hair to grow in people living with sudden hair loss.

People living with an autoimmune disorder that causes sudden hair loss may not have to go bald thanks to a successful drug trial.

A University of Melbourne-led trial found alopecia areata could be treated with two new drugs known as Janus kinase inhibitors.

The randomised placebo-controlled study of patients, aged 18 to 75, evaluated the efficacy and safety of the drugs to treat the condition over 24 weeks.

Professor of Dermatology Rodney Sinclair said the drugs allowed hair to grow.

"This is a game changer," he said.

"Both compounds performed significantly better than placebo in patients with alopecia totalis and alopecia universalis. Both JAK inhibitors were safe and well tolerated."

There is no current effective treatment for the condition which affects up to 147 million people across the globe. But these new results are yet to be published or peer-reviewed.

Professor Sinclair presented the findings at the 27th Congress of the European Academy of Dermatology and Venerology in Paris on Saturday.

Clinics and universities in Australia, Canada and the United States of America are involved in the trial with another to start in the next six to 12 months.