In 2019, research began with users of anti-diabetes treatment medicines, now study shows side effect could be hair loss

Alopecia or hair loss could be a possible side effect of Ozempic-like GLP-1 receptor agonists, particularly semaglutide and tirzepatide, research has found. The findings, published in The British Medical Journal, show that GLP-1RA users were 37 per cent more likely to develop alopecia than SGLT-2 inhibitor users -- diabetes drugs which target kidneys to remove extra sugar from urine -- while they had a 68 per cent higher risk, compared to users of DPP-4 inhibitors.

DPP4-inhibitors are another class of drugs which block the DPP-4 enzyme and stimulate insulin release. All the drugs are prescribed as anti-diabetes treatments.

Researchers, including those from the US' University of Pennsylvania, said that although absolute risk is low, awareness of the potential effect may help inform shared treatment decisions.


"Use of GLP-1 receptor agonists was associated with an increased risk of non-scarring alopecia (where hair follicles remain intact, leaving the potential for regrowth) in adults with type 2 diabetes," the authors wrote.

Rapid weight loss is a well-known trigger of hair shedding and can also lead to iron or zinc deficiencies, which disrupt the hair growth cycle, they said and added hormonal changes may also be relevant.

However, further studies are needed to clarify the underlying mechanisms, the team said.

Electronic patient data from the University of Pennsylvania Health System (Penn Medicine) was analysed to compare rates of alopecia in adults with type 2 diabetes who started using GLP-1 receptor agonists or other types of diabetes drugs including, SGLT-2 inhibitors and DPP-4 inhibitors.

Overall, 12,004 patients using GLP-1 receptor agonists were compared with 15,221 using SGLT-2 inhibitors and a further 11,964 GLP-1 users were compared with 11,233 DPP-4 inhibitor users between January 2019 and September 2024.

The researchers said while the study was a rigorous one, based on high quality data from a large representative cohort, there are limitations.

For example, a lack of clinical information limited the team's ability to assess details such as severity, extent, duration and reversibility of alopecia after stopping treatment. Nor can the authors rule out the possibility that unmeasured factors may have influenced the results.

"Our findings extend previous anecdotal safety signals and provide more systematic evidence to inform clinical awareness of this potential adverse effect," they said.