This is what convinces me caffeine is a drug and not a vitamin or nutrient. If I miss my daily vitamin I don’t even notice but if I miss my daily dose of caffeine it’s difficult for my brain to function on account of the inevitable withdrawal headache.
You would certainly notice if you missed some essential vitamins. The modern diet is just good enough to get you enough of all of them without too much effort.
Alternative hypothesis: Vitamins have a longer half-life in your body, therefore missing a dose does not cause the concentration in your body to drop as quickly.
I’m a poor metabolizer of caffeine and actually it’s far worse when it’s a long half life. I literally can’t sleep until 4am if I drink tea in the morning.
