Is CYP2D6 useful for Darmgesundheit?

CYP2D6 is a key phase I drug-metabolizing enzyme expressed primarily in the liver and intestine. While it metabolizes many drugs and some dietary compounds, there is no direct, clinically relevant evidence linking CYP2D6 genetic variants to gut health outcomes such as microbiome composition, intestinal barrier integrity, or gut inflammation. The main utility of CYP2D6 genotyping lies in pharmacogenetics—predicting drug response and adverse effects. An indirect role in gut health could be hypothesized via local drug metabolism or xenobiotic detoxification, but this remains speculative. Therefore, CYP2D6 testing is not recommended for assessing or improving gut health. For meaningful insights into gut health, validated markers like microbiome diversity, short-chain fatty acids, zonulin, and calprotectin are more appropriate. The evidence level for CYP2D6 in this context is 'mechanistic/unclear'.