GLP-1s tied to higher risk of smell, taste disturbances

Clinical takeaway: Consider counseling GLP-1 patients that smell or taste changes are possible. If complaints do emerge in a user, weigh the drug alongside a standard workup.

GLP-1 receptor agonists now reach millions. But they have an adverse-effect profile that's still coming into focus. Taste disturbance already appears on the label, but smell has drawn far less scrutiny. Preclinical work had suggested these drugs might protect olfactory neurons. A large new cohort study points the other way, tying GLP-1 use in type 2 diabetes to a higher risk of both smell and taste complaints.

Smell and taste loss is more than a quality-of-life problem. In type 2 diabetes it has been tied to neurovascular and neuropathic injury, and flagged as a possible early marker of complications. Against that backdrop, GLP-1 drugs raise a separate question: their receptors sit in both the olfactory bulb and the taste buds, so the drugs themselves might affect chemosensory function. Until now, clinical data testing that link in patients had been thin.

Among 438,474 matched pairs, GLP-1 users had a 48% higher risk of new smell or taste disturbances over two years. The absolute numbers stayed small: 0.37% of users versus 0.22% of controls, a difference that works out to one extra case for every 670 patients treated. This held steady across the two-year follow-up period.

Smell and taste disturbances ran 81% and 52% higher with GLP-1 use, respectively, with parosmia the steepest at 118%. The pattern is notable because taste disturbance, not smell, is what currently appears on the label.

Interestingly, prior preclinical work had pointed to GLP-1 drugs protecting olfactory neurons, through less neuroinflammation and oxidative stress, not harming them. The authors suggest the diabetic nervous system may respond differently, flipping a protective mechanism into a harmful one.

Drawing on electronic health records from more than 170 institutions worldwide, researchers screened more than 7 million adults with type 2 diabetes, then compared those who started a GLP-1 drug against matched patients on other diabetes medications. The groups were balanced on demographics, comorbidities, and other antidiabetic drugs, and disturbances were captured by diagnostic codes.

The finding shifts what to listen for, not what to prescribe. Smell and taste complaints are easy to miss, and GLP-1 use is easy to overlook as the potential reason.

"Discontinuation of therapy should not be routine and should instead be guided by shared decision-making, considering the overall clinical context," the authors concluded.

Source: Zontag J, et al. JAMA Otolaryngol Head Neck Surg. 2026 Jun 25. Smell and taste disturbances among glucagon-like peptide-1 receptor agonist users