Which form you have depends on your genetics.Ģ. However, there are two forms of CYP1A2, one of which will metabolize caffeine faster than the other, meaning you feel less of the stimulant's effects. An enzyme in the liver called CYP1A2 is responsible for 95% of caffeine metabolization. 'Genetics can play a factor in caffeine sensitivity because genetics determines how effectively the body's adenosine receptors can bind to caffeine molecules,' Jenna Liphart Rhoads, PhD, a registered nurse and nurse educator at Nurse Together.Īdditionally, how quickly you feel caffeine's effects and for how long depends on your genetics. This action blocks adenosine from reaching those receptors thereby inhibiting sleepiness. Once there, they bind to receptors normally paired with adenosine, a neurotransmitter that encourages sleep. Then, caffeine molecules quickly move to the brain. What the research says: In a 2011 study, researchers found that about 10% of people carry a gene that makes them hyposensitive to caffeine, allowing for a high caffeine intake while experiencing little to no effect.Īfter ingesting caffeine it takes about 45 minutes for the body to absorb it.

Your genetics may be to blame if you can't feel caffeine's stimulating effects.

Caffeine may not affect you due to your genetics

Doesnt affect me