Hair loss is gaining attention as a side effect of GLP-1 receptor agonists, drugs like tirzepatide and semaglutide, which are used for weight loss and type 2 diabetes. Approximately 20 million individuals across the US, UK, and EU are currently taking these medications.
A survey of GLP-1 users indicated that 20% of respondents experienced hair shedding. However, researchers note that the absence of high-quality data from randomised, controlled trials makes it difficult to determine the exact prevalence of this side effect.
Most hair loss associated with GLP-1 drugs is often temporary and reversible. This is commonly a stress-related condition known as telogen effluvium, where a stressor causes a large number of hair follicles to enter a resting phase before falling out after two to three months. This type of hair loss typically resolves once the stressor is removed.
A smaller number of individuals taking GLP-1s may experience new or increased pattern baldness, which is a genetically influenced and usually permanent form of hair loss. One study found men taking GLP-1 drugs were 7% more likely to experience this type of hair loss.
Possible causes for telogen effluvium in the context of rapid weight loss include the shock of sudden calorie restriction and micronutrient deficiencies. Women account for nearly 90% of reported telogen effluvium cases when taking GLP-1 drugs.