A pharmacist-honest guide to which genetic variants actually matter for over-the-counter medications and supplements, and which claims are overhyped.
Pharmacogenomics is the study of how your genes affect how your body processes medications. While genetic testing has clear applications for some prescription drugs, its relevance to most OTC medications is more limited than direct-to-consumer testing companies often suggest.
Some genetic variants do have documented effects on OTC products. For example, CYP2D6 variants affect codeine metabolism and may impact certain antihistamines. MTHFR variants affect folate metabolism and may be relevant for certain B-vitamin supplements.
Many genetic supplement recommendations rely on weak or mixed evidence. This guide separates what research actually supports from what is primarily marketing.