Can CYP2C19 help with sleep?

CYP2C19 is a gene encoding a drug-metabolizing enzyme (CYP2C19). There is no direct, evidence-based link between CYP2C19 variants and sleep quality or chronotype. The provided context discusses DNA tests for chronotype (e.g., CLOCK/PER) and rates their evidence as 'unclear' or 'GWAS' – CYP2C19 is not mentioned. Indirectly, CYP2C19 polymorphisms may affect the metabolism of drugs that influence sleep (e.g., certain antidepressants), but this is not a direct sleep gene test. Consumer DNA tests for sleep have small effect sizes and are not diagnostic. Validated questionnaires and sleep hygiene are more reliable. Evidence: unclear.