IntroductionImpaired awareness of hypoglycemia (IAH) is a common complication in patients with type-1 diabetes (T1D). IAH is a major risk factor for severe hypoglycemic events, leading to adverse clinical consequences and cerebral damage. Non-invasive, cost-effective, and logistically efficient biomarkers for this condition have not been validated. Here, we propose plasma neurofilament light chain (NfL) levels as a biomarker of neuroaxonal damage in patients with T1D-IAH.Research design and methods54 patients were included into the study (18 T1D-IAH, 18 T1D with normal awareness of hypoglycemia (NAH) and 18 healthy controls). We measured plasma NfL levels and studied cerebral gray matter alterations on MRI.ResultsWe found that NfL levels were increased in patients with T1D-IAH compared with patients with T1D-NAH and healthy controls. Importantly, increased NfL levels correlated with reduced cerebral gray matter volume and increased IAH severity in patients with T1D-IAH.ConclusionOverall, our findings identify plasma NfL levels as a potential biomarker of cerebral damage in this population, motivating further confirmatory studies with potential implications in clinical trials.