The liver's P450 system and gut microbes are primary determinants of drug metabolism variability.

“because normally we think a lot about the num the the different genes in the P4 p450 system in the liver which is heavily responsible for how most drugs are metabolized and that clearly explains a lot of the variability in human metabolism of drugs but I'd never I never knew about this this is even One Step Beyond that and obviously not dependent on our genome but the Genome of this host yeah and these are mostly gut microbes so it really is especially for these oral um uh drugs there is some inter or some you know path that it takes where it's interacting with these microbes and they are able to metabolize um these various drugs”