Misc How can intranasal BA be lower than oral BA?

[ChemicallyEnhanced]

'Cause surely anything that ISN'T absorbed intranasally ends up in the stomach anyway?

 

[fairnymph]

That’s assuming that you rinse your nose repeatedly, which most do not. But even if you do that, it’s going to more gradually drip down & undergo first pass metabolism instead of all of it being absorbed & metabolised at once.