It takes caffeine around 30 – 45 mins to be absorbed through the intestines.
The main enzyme responsible for breaking caffeine down in the intestines and liver is CYP1A2.
CYP1A2 is largely responsible for our individual tolerance to caffeine. A well researched variant in the CYP1A2 gene is known to increase caffeine metabolism which is associated with fewer negative symptoms such as jitters, anxiety and hypertension whereas those without the variant process caffeine more slowly and are more susceptible to the negative effects. The Paraxanthine (see diagram below) metabolite is metabolised further via CYP1A2, CYP2A6 & NAT2.
Diet and lifestyle factors also influence the metabolism of caffeine: ⬆️ Inducers – nicotine 🚬, intense exercise, cruciferous veg, grilled meat ⬇️Inhibitors – certain medication including SSRIs, pregnancy and the OCP.
Our VitaGEN report covers the CYP1A2 variant. Find out if you are a fast or slow caffeine metaboliser and what what to do about it…