July 22, 2026

expert reaction to a target trial emulation study on risk of hair loss associated with GLP-1 RAs in adults with type 2 diabetes

A study published in The BMJ looks at GLP-1 use and the risk of hair loss. 

Dr Marie Spreckley, Weight Management Researcher, University of Cambridge, said:

“This is a well-conducted observational study that used a target trial emulation approach with active comparator groups, extensive adjustment for measured confounders, and multiple sensitivity analyses, all of which strengthen confidence in the findings. However, as with all observational studies, it cannot establish causality, and the possibility of residual confounding remains.

“The study found that GLP-1 receptor agonist use was associated with a higher relative risk of clinically recorded non-scarring hair loss than two alternative classes of diabetes medication. However, it is important to interpret these findings alongside the absolute risk, which remained low at 6.91 cases per 1,000 person-years among GLP-1 receptor agonist users, compared with 5.04 and 3.89 cases per 1,000 person-years in the comparator groups. In practical terms, this means around two to three additional clinically recorded cases of hair loss per 1,000 person-years of treatment compared with the alternative diabetes medications.”

“The authors also note that rapid weight loss is a recognised trigger for temporary hair shedding. Nutritional deficiencies, such as iron or zinc deficiency, may also contribute, although this study was not designed to distinguish between these potential mechanisms or determine whether hair loss resolved after treatment.

“Overall, this study provides important evidence that clinicians and patients should be aware of this potential adverse effect, but it should be interpreted in the context of the substantial and well-established benefits of GLP-1 receptor agonists for improving glycaemic control, reducing body weight, and lowering the risk of obesity-related complications. For many people, those benefits are likely to outweigh this relatively small potential risk.”

‘Risk of hair loss associated with glucagon-like peptide-1 receptor agonists in adults with type 2 diabetes: target trial emulation’ by Huilin Tang et al. was published in The BMJ at 23:30 UK time Wednesday 22 July 2026. 

DOI: 10.1136/bmj-2026-100077

Declared interests

Dr Marie Spreckley: “Dr Marie Spreckley is a Postdoctoral Researcher at IMS Epidemiology, University of Cambridge, where her research focuses on obesity, nutrition and incretin-based therapies. She has no personal financial interests, consultancy roles, advisory positions, speaker fees, stock ownership, or honoraria from manufacturers of GLP-1 or GIP/GLP-1 receptor agonists.”