New-Onset Alopecia Is Significantly Higher with Tirzepatide Than with Semaglutide, Even After Weight-Loss Matching

A recent study involving 12,863 matched users of tirzepatide and semaglutide found that new-onset alopecia was significantly more frequent in those using tirzepatide, with an incidence of 4.20% compared to 2.88% in semaglutide users, resulting in a risk ratio of 1.46. This trend persisted even after accounting for weight loss, suggesting factors beyond weight loss, possibly related to tirzepatide's pharmacology, contribute to the higher alopecia incidence. The study also noted that female sex, hypothyroidism, and lower baseline weight were more common among those who developed alopecia, and that tirzepatide users were more likely to initiate hair loss treatments like minoxidil.