BMJ study links GLP-1 diabetes drugs to a higher risk of non-scarring hair loss

A target trial emulation in The BMJ, using University of Pennsylvania health records, compared adults with type 2 diabetes who started a GLP-1 receptor agonist with those who started an SGLT-2 or DPP-4 inhibitor. GLP-1 drug use was associated with a higher risk of alopecia (hazard ratio 1.37 versus SGLT-2 inhibitors and 1.68 versus DPP-4 inhibitors), and the excess was in non-scarring hair loss. Absolute rates were low, 6.91 versus 5.04 cases per 1,000 person-years in the first comparison, and the study is observational, so it cannot show that the drugs cause hair loss.