GLP 1 Receptor Agonists Linked to Hair Loss Risk

GLUCAGON like peptide 1 receptor agonists (GLP-1 receptor agonists) were associated with a higher risk of incident non-scarring alopecia in adults with type 2 diabetes compared with sodium glucose cotransporter 2 inhibitors (SGLT-2 inhibitors) and dipeptidyl peptidase 4 inhibitors (DPP-4 inhibitors), according to a target trial emulation using electronic health record data.

Researchers analysed adults aged over 18 years with type 2 diabetes who newly initiated GLP-1 receptor agonists, SGLT-2 inhibitors, or DPP-4 inhibitors between January 2019 and September 2024. The study used electronic health records from Penn Medicine and assessed incident alopecia and its subtypes using diagnostic codes.

To minimise differences between treatment groups, stabilised inverse probability of treatment weighting was applied to balance baseline characteristics. Cox proportional hazards models were then used to estimate the association between treatment and incident alopecia.

Increased Risk Was Consistent Across Analyses

The analysis included 12,004 patients initiating GLP-1 receptor agonists and 15,221 initiating SGLT-2 inhibitors. A second comparison included 11,964 GLP-1 receptor agonist initiators and 11,238 DPP-4 inhibitor initiators.

Following adjustment, GLP-1 receptor agonist use was associated with a higher risk of alopecia than SGLT-2 inhibitors: (hazard ratio: 1.37; 95% CI: 1.08–1.73). A similar association was observed when compared with DPP-4 inhibitors: (hazard ratio: 1.68; 95% CI: 1.28–2.20).

The associations remained consistent across sensitivity and subgroup analyses, although they were attenuated after negative control outcome calibration.

Association Was Limited to Non-Scarring Alopecia

Subtype analyses indicated that the increased risk was specific to non-scarring alopecia. Compared with SGLT-2 inhibitors, GLP-1 receptor agonists were associated with a higher risk of non-scarring alopecia: (hazard ratio: 1.53; 95% CI: 1.18–1.97). The association was also observed in comparison with DPP-4 inhibitors: (hazard ratio: 1.72; 95% CI: 1.28–2.31).

Although the investigators noted that the absolute risk of alopecia was low, the findings suggested that awareness of this potential adverse effect may help inform treatment decisions for adults with type 2 diabetes. Further research may clarify the mechanisms underlying the observed association and its implications for long term diabetes management.

Reference

Tang H et al. Risk of hair loss associated with glucagon-like peptide-1 receptor agonists in adults with type 2 diabetes: target trial emulation. BMJ. 2026;394: doi: https://doi.org/10.1136/bmj-2026-100077.

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