GLP-1 Agonists Linked to Higher Alopecia Risk

Key Takeaways

• In adults with type 2 diabetes, GLP-1 receptor agonist use was associated with a 68% higher alopecia risk than DPP-4 inhibitor use, with rates of 6.53 versus 3.89 per 1,000 person-years.
• In adults with type 2 diabetes, GLP-1 receptor agonist use was associated with a 37% higher alopecia risk than SGLT-2 inhibitor use, with rates of 6.91 versus 5.04 per 1,000 person-years.
• Further analyses indicated that the reported hair-loss signal with GLP-1 receptor agonists was specific to nonscarring alopecia, with risk increases of 72% versus DPP-4 inhibitors and 53% versus SGLT-2 inhibitors, while absolute risk remained low.

In a BMJ study, adults with type 2 diabetes starting GLP-1 receptor agonists had higher reported alopecia rates than those starting other glucose-lowering drugs, with the strongest comparator result showing a 68% higher risk versus DPP-4 inhibitors and rates of 6.53 versus 3.89 per 1,000 person-years.

The analysis was a target trial emulation using University of Pennsylvania Health System electronic patient data from January 2019 through September 2024 in adults with type 2 diabetes. Researchers compared 12,004 GLP-1 receptor agonist users with 15,221 SGLT-2 inhibitor users and separately compared 11,964 GLP-1 receptor agonist users with 11,233 DPP-4 inhibitor users. Prior reports had raised alopecia as a possible adverse effect of GLP-1 receptor agonists, particularly semaglutide and tirzepatide.

Analyses adjusted for age, sex, ethnicity, pre-existing conditions, other medication use, and body mass index. GLP-1 receptor agonist users were younger and had higher body mass index than comparator groups, with mean age and body mass index of 58 and 36.2 versus 65 and 32.3 in the SGLT-2 comparison, and 58 and 36.2 versus 67 and 31.3 in the DPP-4 comparison.

The authors reported that the association was specific to nonscarring alopecia, but the available data could not assess alopecia severity, extent, duration, or reversibility after treatment discontinuation, and unmeasured factors may have influenced the findings.

Clinician Questions

How much higher was alopecia risk with GLP-1 receptor agonists than with DPP-4 inhibitors in adults with type 2 diabetes?

In adults with type 2 diabetes, GLP-1 receptor agonist use was associated with a 68% higher alopecia risk than DPP-4 inhibitor use, with rates of 6.53 versus 3.89 per 1,000 person-years.

How did alopecia rates with GLP-1 receptor agonists compare with SGLT-2 inhibitors in adults with type 2 diabetes?

In adults with type 2 diabetes, GLP-1 receptor agonist use was associated with a 37% higher alopecia risk than SGLT-2 inhibitor use, with rates of 6.91 versus 5.04 per 1,000 person-years.

Was the reported hair-loss signal with GLP-1 receptor agonists limited to nonscarring alopecia?

Further analyses indicated that in adults with type 2 diabetes, the association with GLP-1 receptor agonists was specific to nonscarring alopecia, with increased risks of 53% versus SGLT-2 inhibitors and 72% versus DPP-4 inhibitors.

What study population and data source were used to compare GLP-1 receptor agonists with other diabetes drugs for alopecia risk?

Researchers used University of Pennsylvania Health System electronic patient data to compare adults with type 2 diabetes who started GLP-1 receptor agonists with adults starting SGLT-2 inhibitors or DPP-4 inhibitors, using data from January 2019 through September 2024.