According to Peat, a hypersensitivity to coffee and other stimulants can be explained by a lack of CO2.
I've been able to prove this to myself by taking TTFD with coffee and drinking coffee without it. Night and day difference.
Theanine was also helpful but not as much.
When you're B12 deficient (as most everyone with upper digestive disorder is), you're missing out on the primary achievement of the human race, which is the functionality of an extremely dense nervous system.
Liposomal is the way.