A GIP/GLP1 (Glucose-dependent insulintropic peptide/Glucagon-like peptide 1) co-agonist peptide or derivative for use in the treatment of a neurological disorder. The peptide represented by Formula I: YXEGTFTSDYSIYLDKQAAXEFVXWLLAG-Y1 where X is amino-isobutyric acid and Y1 is absent or at least 8 residues. The neurological disorder may be a neurodegenerative disorder such as Alzheimers disease, Parkinsons disease and stroke. Also included in the present invention are inter alia pharmaceutical compositions comprising a GIP/GLP1 co-agonist peptide for use in treatment of such disorders, together with methods of treating such disorders as well as other subject matter.
