I don't know if you can take too much b-12 sublingually, but I do know this:
If you overtake folic acid, and have blood tests, and your doctor is looking at your b-12 levels, you can have a false testing.
Folic acid masks a low b-12 count and THAT can be deadly.
B-12 is necessary in the right amounts for the nervous system.
I take injections twice a month for anemia, prescribed by my doctor.
You can also over do vitamin A, and iron.
I take vitamins, but I don't overdo ANY of them, unless told to by my physician. Just something for ppl to think about, cause mousie cares about you :XD: