A recent study suggests hair loss could be a potential side effect of semaglutide, the active ingredient in the popular weight loss drugs Ozempic and Wegovy.

Researchers at the University of British Columbia (UBC) in Canada found that people taking semaglutide for weight loss had more hair loss than people taking bupropion-naltrexone, another weight loss drug that is not a GLP-1—the class of medications that includes semaglutide and other new-generation obesity drugs.

The study, which was published on the preprint server MedRxiv and has not been peer-reviewed, is the first of its kind, according to first author Mohit Sodhi, MD, a researcher and emergency medicine resident physician at UBC.

“There were many anecdotal reports, case studies, and reports to the FDA of hair loss, but no studies investigated this risk in a real-life clinical setting,” Sodhi told Health. 

Researchers analyzed the health information of 1,926 people taking semaglutide for weight loss. They excluded people with a diagnosis of diabetes or who had been prescribed an antihyperglycemic medication. The team also looked at data from 1,348 people taking bupropion-naltrexone, sold as Contrave.

“Bupropion-naltrexone was used as an active comparator because it is chemically distinct to semaglutide and to control for confounding by indication, meaning that both the cases and controls under investigation were using these medications for weight loss,” Sodhi said.

The chances of being diagnosed with a hair loss condition was 26.5 out of 1,000 for those taking semaglutide and 11.8 out of 1,000 for those taking bupropion-naltrexone. Women had a more than doubled increase in hair loss when taking semaglutide, a stronger risk than men did.

“Our results were in fact validated by the Wegovy clinical trials, where they had a similar risk ratio to our study,” Sodhi said.

The research is preliminary, and further studies are necessary to determine whether women are truly most at risk for hair loss and whether semaglutide actually causes hair loss to begin with.

However, doctors say GLP-1 patients often do report hair-related side effects.

“This rapid type of hair loss is something that we actually do commonly see in patients with GLP-1’s,” Saami Khalifian, MD, a double board-certified dermatologist and cosmetic surgeon who was not connected to the UBC study, told Health.

He said his patients often present with telogen effluvium, a non-scarring form of hair loss resulting from a speedier hair cycle, which causes more hair to shed. It tends to self-resolve over time.

Brynna Connor, MD, a board-certified family medicine physician who regularly works with patients taking GLP-1 drugs and was not connected to the UBC study, also said her patients note hair loss after taking these medications. “Next to the constipation and diarrhea, it’s probably the top concern people have,” she told Health.

Although more research is needed to explain the mechanism behind the potential connection between hair loss and semaglutide, researchers believe that weight loss—not semaglutide itself—is causing the problem.

“One factor could be due to the physiological stress that rapid weight loss can induce, leading to disruption of the natural hair cycle,” Sodhi says. “This may be more prominent with semaglutide, as it is known to decrease weight more rapidly than bupropion-naltrexone, thus inducing greater physiological stress on the body and thus potentially greater hair loss.”

Significant physiological or emotional stress can temporarily cause people to lose their hair. “Sometimes when people get pregnant, they lose their hair,” Khalifian said. “Or you get COVID, you lose your hair. You have a massive emotional stressor, you lose a lot of hair.”

Sodhi explained that semaglutide’s effect on appetite may also be another explanation for hair loss. GLP-1 medications slow gastric emptying, making people feel full for longer and eat far less than they used to. “The biggest problem I see with these is that people aren’t eating enough,” Connor said.

Hair will be affected if people aren’t getting enough protein and other nutrients in their diets. “You’re just not giving your body the nutrients that it needs to create and push out hair,” Khalifian said.

Getting adequate nutrition is crucial for many reasons while taking GLP-1 medications, including to maintain hair health. 

Khalifian recommended front-loading meals with protein. “Eat the protein first because by the time you get to the carbs, you might be full,” he says. “If you go the other way, you’re not going to be hungry for the protein if you eat the carbs first.” 

Connor said some supplementation might be needed if people aren’t getting adequate nutrients through diet alone. Biotin (vitamin B7) may be beneficial for stronger hair, skin, and nails. 

Topical minoxidil or other treatments to stimulate hair growth may also be an option, Khalifian noted.

Before starting any GLP-1, Connor recommends getting lab work done to determine if you have any underlying conditions that could also contribute to hair loss, such as anemia or thyroid disorders. If you are susceptible to hair loss but start a GLP-1 anyway, she suggests working with a dietitian to develop a nutrition plan.

“Everything you put in your body is going to count even more, so you’ve got to make sure it’s nutritious food,” Connor said.

Be sure to talk to your healthcare provider, who can help you weigh the benefits and risks of weight loss medications.

“The risk-benefit calculus for someone who may be morbidly obese or has very uncontrolled diabetes versus someone who may be using these medications for recreational weight loss, such as wanting to lose 10 pounds before a special event, is very different,” Sodhi said. “Those with more significant disease may be more willing to accept potential adverse events like hair loss compared to someone who is using these medications for more recreational purposes.”