Evidence check: CYP1A2 in the context of allergy

Evidence for CYP1A2 in the context of allergy is moderate and mostly mechanistic. CYP1A2 is a liver enzyme that metabolizes caffeine and some antihistamines (e.g., fexofenadine). Some studies suggest that the CYP1A2*1F polymorphism (rs762551) affects enzyme activity: carriers of the AA variant (rapid metabolizers) may clear certain drugs faster, potentially reducing antihistamine efficacy. However, no robust clinical trials directly link CYP1A2 variants to allergy symptoms or treatment outcomes. Consumer DNA tests like MyBody-X typically test only a few variants and cannot provide comprehensive pharmacogenetic guidance. Moreover, CYP1A2 is primarily associated with caffeine metabolism – extrapolation to allergy is speculative. Marketing claims about 'allergy genes' should be viewed skeptically. Safety note: Never change your medication based solely on a genetic test. Discuss results with a physician, especially if you take antihistamines or other drugs.