GLP-1 drugs commonly used to manage type 2 diabetes and obesity may be associated with a small increase in hair loss, according to published research. BMJ July 22, 2026.
This drug class includes semaglutide, sold under brand names such as Ozempic and Wegovy, and tirzepatide, sold under brand names such as Mounjaro and Zepbound. Researchers found that adults with type 2 diabetes who took GLP-1 receptor agonists developed hair loss more often than patients taking two other common diabetes medications.
Although the relative increase was significant, the researchers emphasized that the absolute risk of hair loss remains low. Still, knowing about possible side effects can help patients and clinicians make more informed treatment decisions together.
Reports of hair loss related to Ozempic and similar drugs
Hair loss has been previously reported as a possible side effect of drugs containing GLP-1 receptor agonists, particularly semaglutide or tirzepatide. However, there are limited studies that directly compare the risks of GLP-1 users to those of patients receiving other diabetes treatments.
For the study, researchers analyzed electronic medical records at the University of Pennsylvania Health System (Penn Medicine). They compared hair loss rates in adults with type 2 diabetes who started treatment with GLP-1 receptor agonists, SGLT-2 inhibitors, or DPP-4 inhibitors.
The analysis included patients treated between January 2019 and September 2024. One comparison included 12,004 people taking GLP-1 receptor agonists and 15,221 people taking SGLT-2 inhibitors. Another comparison included 11,964 GLP-1 users and 11,233 people taking DPP-4 inhibitors.
Researchers explained differences between patients
The groups differed in several important ways before the researchers adjusted the results.
Compared to those taking SGLT-2 inhibitors, GLP-1 users were younger (mean age 58 vs. 65 years), had a higher body mass index (36.2 vs. 32.3), and had lower rates of cardiovascular disease and chronic kidney disease.
A similar pattern emerged in comparison with DPP-4 inhibitors. GLP-1 users were younger (mean age 58 vs. 67) and had higher BMI (36.2 vs. 31.3).
The researchers adjusted for factors that could influence the results, including age, gender, ethnicity, pre-existing conditions, use of other medications, and body mass index.
GLP-1 users had higher rates of alopecia
After these adjustments, GLP-1 receptor agonist use was associated with a 37% higher risk of alopecia compared with SGLT-2 inhibitor use (6.91 vs. 5.04 per 1,000 person-years).
When GLP-1 users were compared to those using DPP-4 inhibitors, the risk was 68% higher (6.53 vs. 3.89 per 1,000 person-years).
Further analysis suggested that this association was limited to non-scarring alopecia (where the hair follicles are intact and the potential for regrowth remains). The risk of this form of hair loss was 53% higher in GLP-1 users than in SGLT-2 inhibitor users and 72% higher than in DPP-4 inhibitor users.
Rapid weight loss can affect hair cycle
The study did not prove why GLP-1 drugs were associated with hair loss. However, the authors pointed to several possible explanations.
It has been established that rapid weight loss is a cause of increased hair loss. It can also contribute to iron and zinc deficiencies, both of which can interfere with the normal hair growth cycle. Hormonal changes related to weight loss and treatment may also play a role, but additional research is needed to identify the underlying mechanisms.
important questions remain
The researchers acknowledged some limitations. The available clinical records did not provide sufficient details to determine the severity, extent, and duration of the alopecia. The research team also could not assess whether hair grew back after the patients stopped taking the drug.
Additionally, this observational study cannot prove that GLP-1 drugs directly caused hair loss. Other factors that were not measured may have influenced the results.
Still, the authors described the study as rigorous and noted that high-quality data from a large and representative group of patients was used. The results remained consistent across additional analyses, supporting their reliability.
The researchers concluded, “Our findings extend previous anecdotal safety signals and provide more systematic evidence to inform clinical awareness of this potential side effect.”
