Although DPP-4 inhibitors do not cross the BBB under normal conditions (the pharmacokinetic feature may prevent their repurposing use in neurodegenerative diseases), the permeability of BBB is increased in neurodegenerative diseases, so molecules otherwise unable to cross BBB could enter into CNS in these conditions (103)
That tradeoff only makes sense when a clinician sees a clear reason in your case
71: 467989 Midtvedt T, Bjorneklett A, Carlstedt-Duke B, Gustafsson BE, Hoverstad T, Lingaas E, et al
The best approach is to assume coverage is uncertain until your plan is checked
This amino acid combined with fumeric acid (fumerate), actively supports endurance for athletes, and heart muscles and is known as a cardiovascular nutrient