Mag citrate is very affordable and easy to find.

My doc suggests target B12 levels of 800 to 1000 pg/mL and folate of about 20 ng/mL.

The B12 is just above the high end of the common suggested range of 200 to 840. The folate is at the top of the suggested range.

Healthy brains may do fine at the lower ranges but healing and stress are a big consumers of B12 and B6.