GFAP and concussion: However, incretin mimetic use for TBI and concussion treatment will require early-phase clinical studies that focus on specific windows of intervention (e.g., acute vs. subacute), carefully chosen populations (mild concussion vs. moderate/severe TBI), and validated outcome measures (cognitive composites, blood-based biomarkers such as GFAP/NfL, and advanced imaging readouts of BBB integrity or neuroinflammation).