Kyle Rhodes, who was bald due to a rare autoimmune disease called alopecia areata, grew back a full head of hair when his doctor treated him with the drug Xeljanz.

The drug is normally used to treat rheumatoid arthritis, another autoimmune disorder.

After having experienced complete hair loss, Rhodes grew back a full head of hair, eyebrows and eyelashes, according to Medical News Today.

Dr. Brett King, Rhodes’ dermatologist, is eager to try the treatment out on other patients.

“I was truly overjoyed for him,” King told CNN.

He intends on creating a cream version of the drug so that users don’t have to send the medicine through their entire body with a pill.

But not every doctor was as ecstatic about the results.

Dr. George Cotsarelis, chairman of dermatology at the University of Pennsylvania’s Perelman School of Medicine, warned that the drug could have “nasty side effects.”

The drug is not currently believed to cure regular baldness that occurs from aging, but King believes the idea should be further explored.