It is well-known that people metabolize caffeine with different speed due to genetic reasons. Therefore people can experience wildly different peak blood concen

It is well-known that people metabolize caffeine with different speed due to genetic reasons. Therefore people can experience wildly different peak blood concentration after drinking many cups per day. I suppose it influences how strong withdrawals are. I personally used to drink a lot of coffee and rarely experienced any withdrawal effects. I also know (from comparing myself with other people) that I am a very fast caffeine metabolizer.