(CNN) Though it's normal to lose up to 100 hairs from your scalp every day, excessive hair loss is distressing. But a drug originally developed to treat osteoporosis may soon help those who want to treat or even reverse baldness, according to research published Tuesday in the journal PLOS Biology.
The path to finding this new compound began with an immunosuppressive drug, cyclosporine A, that has been used since the 1980s to treat patients undergoing transplant surgery or struggling with autoimmune diseases.
Cyclosporine A has some severe side effects, including convulsions and diarrhea, yet some patients have experienced something quite unusual: unwanted hair growth.
Sensing a possible answer to baldness, researchers from the University of Manchester's Centre for Dermatology Research decided to investigate by analyzing the drug's impact on gene expression.
They found that cyclosporine A quiets a certain protein (commonly known as SFRP1) that inhibits hair growth. When the silencer is silenced, raucous hair growth occurs.
The research team searched for another compound with a similar mechanism of action and found WAY-316606, which was developed to treat osteoporosis.
After applying WAY-316606 to hair follicles in a lab, the researchers found that it did an even better job of growing hair than cyclosporine A.
This "demonstrates that WAY-316606 is a promising new pharmacological promoter of human hair growth," the study authors wrote, adding that they expect any side effects to be less toxic than those of cyclosporine A.
The next step is clinical trials to see whether topical use of this compound is safe and effective for humans.
Dr. Doris Day, a dermatologist at Lenox Hill Hospital in NYC, said she feels hopeful that this research will result in a new medication and "bring us a step closer to finding permanent ways to help prevent hair loss and regrow hair."
Day, who was not involved in the study, said she's seen "many strides" in hair loss research over the past decade with research focused on both the immune system and genetics.
"Now, we have treatments that are available," she said.
Originally, minoxidil was approved to treat high blood pressure, while finasteride was intended for the treatment of an enlarged prostate.
Today, minoxidil is US Food and Drug Administration-approved for the treatment of both male and female pattern baldness; finasteride is FDA-approved for male pattern baldness and sometimes used off-label for hair loss in women.
Most recently, autoimmune drugs known as Janus kinase inhibitors -- JAK inhibitors -- have been found to produce a full head of hair in patients with moderate to severe alopecia areata, a type of baldness that affects both men and women.
These drugs are in clinical trials (tested on humans) to see whether they are safe and effective for the treatment of alopecia universalis, a genetic disease that causes complete hair loss on the scalp and body, Day said.
"I've had patients who have had no hair on any part of their bodies for 10 years who now have all their hair back," she said of JAK inhibitors.
"Hair loss is not just an aesthetic thing. It really does affect someone's self-esteem and their sense of well-being," she said, adding that 30% of her practice deals with hair loss. "People come in devastated, near suicidal over hair."
Hair, being a fundamental way we project ourselves to the world, is important to many people, she said.
"The hardest thing I have to explain to patients right now is that what I do for hair loss, we have to continue doing over time," Day said. If patients stop taking the medicine, they lose the benefit, often finding even more hair gone than before they started.
Another downside of hair growth products is that they can make your hair feel greasy or your scalp itchy.
Ultimately, a permanent hair loss solution will be found in some form of stem cell treatment, Day believes: "When there's money to be made, there's research that's going to be done."