Danish pharmaceutical company Novo Nordisk's glucagon-like peptide-1 (GLP-1) class obesity drug Wegovy (ingredient name semaglutide) has been found to carry a 52% higher risk of hair loss side effects compared to existing appetite suppressants. This suggests that if there is a significant risk of hair loss, one should reconsider the use of obesity treatments.
A research team led by Professor Mahyar Etminan at the University of British Columbia (UBC) compared adults with obesity who were prescribed semaglutide (1,926 people) and the appetite suppressant bupropion-naltrexone's Contrave (1,348 people) in the U.S. between 2006 and 2020, resulting in these findings. The results of this study were published last month on the medical paper sharing site medRxiv.
Wegovy is a drug that mimics the glucagon-like peptide (GLP)-1 hormone secreted from the small intestine when food is consumed. Originally developed to regulate blood sugar by promoting insulin secretion, it was later found to confirm weight-loss effects and evolved into an obesity treatment. Wegovy helps feel full longer with smaller meals by slowing digestion. The U.S. company Eli Lilly's Mounjaro is also a GLP-1 class diabetes and obesity treatment.
GLP-1 class drugs have shown therapeutic effects in various diseases, including diabetes, obesity, and obesity-related complications such as obstructive sleep apnea, fatty liver disease, cardiovascular diseases, and Alzheimer's disease. On the other hand, several significant side effects, such as nausea and vomiting, as well as muscle wasting and suicidal impulses, were also found in clinical trials.
Hair loss is one of the side effects confirmed in clinical trials. About 3% of severely obese adults and approximately 4% of adolescents aged 12 to 17 experienced hair loss side effects in the phase 3 clinical trial of Wegovy. Subsequently, numerous cases of patients in the U.S. treated with Wegovy complaining of hair loss symptoms were reported. This research result supports that.
The UBC research team analyzed that semaglutide's strong appetite-suppressing effects could lead to nutritional deficiencies, increasing the risk of hair loss. Research Institute member Mohit Sodhi noted, "The appetite-suppressing ability induces patients to take in less food, which can particularly lead to protein deficiencies that are significantly related to hair loss."
The research team also stated that GLP-1 class drugs could disrupt the hair cycle, leading to hair loss. Research Institute member Sodhi explained, "Rapid weight loss induces physiological stress, which can disrupt the natural hair cycle, and Wegovy's effects result from losing weight faster than Contrave."
The research team analyzed that GLP-1 class drugs could induce hormonal changes that increase the risk of hair loss symptoms, including 'telogen effluvium,' where hair fails to complete its growth phase, and androgenic alopecia, commonly referred to as male pattern baldness. Telogen effluvium occurs when stress factors such as rapid weight loss disrupt the hair growth cycle, halting follicle growth.
Experts advise that obese patients concerned about hair loss need to reconsider using GLP-1 class obesity drugs, such as semaglutide. Dr. Priya Jaisinghani of NYU Langone Health said, "GLP-1 class obesity drugs can lead to side effects like hair loss due to significant weight loss effects, making it important to discuss prescriptions for obesity drugs with a physician for a safe and sustainable weight loss rate." Research Institute member Sodhi also stated, "Both physicians and patients understanding the effects as well as the side effects of the drugs will help in choosing prescribed medications."
However, Research Institute member Sodhi said that additional studies are needed to gain a detailed understanding of the correlation between hair loss and semaglutide. He noted, "This study analyzed prescription patient data over a specific period, and further research is necessary to determine whether hair loss symptoms improve after discontinuing semaglutide. "
References
medRxiv (2025), DOI: https://doi.org/10.1101/2025.02.23.25322568