GCG and Parkinson disease: Furthermore, guideline doses used in TDM2 may not be sufficient to achieve the brain concentrations required to maximize the neuroprotective effect in PD, suggesting that pharmacokinetic adjustments or structural optimization would be necessary to maximize the neuroprotective effect, either through higher tolerable doses or preferably through structural optimization of analogues to improve brain access, as is being explored with dual GLP-1/GIP agonists.