GLP-1 Receptor Agonists Linked to Hair Loss Risk, Survival Benefits in Brain Metastases

The risk for nonscarring hair loss is increased in association with glucagon-like peptide-1 receptor agonist use, according to a study published online February 9 in the Journal of the American Academy of Dermatology. Meanwhile, separate research suggests that GLP-1 receptor agonist use was associated with significant reduction in all-cause mortality among patients with cancer with brain metastases and type 2 diabetes.

Researchers used the TriNetX US Collaborative Network to examine the incidence and risk for nonscarring hair loss in adults aged 18 to 89 years and adolescents aged 12 to 17 years treated with GLP-1 receptor agonists versus matched controls from 2014 to 2024. Data were included for 547,993 matched adult GLP-1 receptor agonist users and controls.

For both GLP-1 receptor agonist users and controls, there was an increase in the incidence of nonscarring hair loss, telogen effluvium, androgenetic alopecia, and alopecia areata between 2014 and 2024. Incidence curves for overall nonscarring hair loss began to diverge around 2019, with consistently higher rates for GLP-1 receptor agonist users by 2023 to 2024. For telogen effluvium and androgenetic alopecia, the rates remained similar until 2021 to 2022, followed by a sharper increase among GLP-1 receptor agonist users.

GLP-1 receptor agonists were linked to a significantly higher risk for androgenetic alopecia and nonscarring hair loss at six months, with adjusted odds ratios of 1.62 and 1.26, respectively. Risks increased for telogen effluvium, androgenetic alopecia, and nonscarring hair loss at 12 months, with adjusted odds ratios of 1.76, 1.64, and 1.40, respectively. Awareness of alopecia risk in patients on GLP-1 receptor agonists is critical for early detection, anticipatory guidance, and multidisciplinary care.

In the brain metastases cohort study, the findings suggest that glucagon-like peptide-1 receptor agonist use was associated with significant reduction in all-cause mortality among patients with cancer with brain metastases and type 2 diabetes, with generally consistent association across subgroups. These results build upon existing evidence that GLP-1 receptor activation modulates pathways relevant to neuro-oncologic health, including attenuation of neuroinflammation, preservation of blood–brain barrier integrity, and reduction of oxidative stress and mitochondrial dysfunction.

Regarding thyroid cancer concerns, the rapid clinical adoption of GLP-1 receptor agonists for the management of type 2 diabetes and obesity has been accompanied by persistent questions regarding their oncological safety. Although FDA labeling includes a boxed warning for medullary thyroid carcinoma, clinicians often face challenges in reconciling animal-model data with real-world patient care. Patients were asking if it was safe to use their GLP-1 therapy with nodular disease and a history of thyroid cancer or concern for thyroid cancer.

A screening of totally asymptomatic women with no known thyroid nodules or thyroid conditions for thyroid cancer showed 2.4% of women who were asymptomatic without known disease have thyroid cancer. The incidence of thyroid cancer amongst women 25 to 50 years of age is even greater than the incidence of breast cancer, which was thought to be the No. 1 malignancy in that age group.

The concern about medullary thyroid cancer has only been shown in animals, and it's only been shown to affect something called the C-cells, which produce medullary thyroid cancer. No other cells or cell type of the thyroid gland are of issue. Even this evidence has never been shown in humans, meaning the studies that have looked at the incidence of thyroid cancer and medullary thyroid cancer in humans with GLP-1 therapy have not shown any effect whatsoever. Because of the animal studies, it is contraindicated in those with medullary thyroid cancer or a history of multiple endocrine neoplasia syndrome.

There is no relationship to GLP-1 therapy in the incidence of thyroid cancer or the incidence of medullary thyroid cancer. There have been no human studies; therefore, there's no relevance whatsoever. Anyone with medullary thyroid cancer should be screened for hereditary disease, which is standard practice.