Glucagon-like peptide-1 (GLP-1) receptor agonists, which are primarily used to treat type 2 diabetes and obesity, are associated with a significantly higher risk of hair loss compared with other diabetes medications, according to a new study published in The BMJ.
Although such cases are uncommon, some people taking semaglutide and tirzepatide have reported hair loss, Euronews reports. The new study confirms that the overall risk remains low, and the authors say the findings could help patients make more informed decisions about treatment.
Importantly, most cases of GLP-1-associated hair loss observed in the study were reversible because the hair follicles remained intact, the authors noted.
“Although the absolute risk of clinically documented alopecia associated with GLP-1 receptor agonists is low, the observed association may still affect patient satisfaction, treatment adherence, and decisions about starting or continuing therapy,” the authors wrote.
The researchers analyzed electronic health records of patients receiving medications for type 2 diabetes, including GLP-1 receptor agonists and two other classes of alternative diabetes drugs: sodium-glucose cotransporter-2 (SGLT-2) inhibitors and dipeptidyl peptidase-4 (DPP-4) inhibitors. Compared with SGLT-2 inhibitors, GLP-1 receptor agonists were associated with a 37% higher risk of alopecia, while the risk was 68% higher compared with DPP-4 inhibitors.
GLP-1 drugs were originally developed to treat type 2 diabetes, but their use has expanded over time to include weight management, reducing cardiovascular risk, and treating obstructive sleep apnea.
These medications work by mimicking glucagon-like peptide-1, a hormone produced in the gut after eating. They activate receptors in the pancreas, stimulating insulin secretion, as well as receptors in the brain that help regulate appetite.
The authors note that rapid weight loss and reduced calorie intake are well-established factors that can trigger increased hair shedding.
Hormonal changes may also play a role, they said, but further research is needed to clarify the underlying mechanisms. Restricting calorie intake can increase physiological stress and lead to deficiencies in micronutrients such as iron, zinc, and biotin, which may disrupt the hair growth cycle.
Although hair loss does not usually cause direct physical harm, it can have significant psychosocial effects, affecting self-esteem, quality of life, and adherence to treatment, the authors added.
The researchers conclude that further studies are needed to clarify the mechanisms linking GLP-1 receptor agonist therapy, weight loss, and hair loss, as well as to identify patients who may be at the greatest risk of this side effect.
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