Following ingestion, caffeine is ra

Following ingestion, caffeine is rapidly and essentially
completely absorbed from the gastrointestinal tract
into the bloodstream. Maximum caffeine concentrations
in blood are reached within 1–1.5 h following
ingestion. Absorbed caffeine is readily distributed
throughout the entire body. It passes across the
blood–brain barrier, through the placenta into amniotic
fluid and the foetus, and into breast milk.
Caffeine has also been detected in semen (Berger
1988, Arnaud 1999).