Myths vs facts: CYP2D6 and blood sugar

There is no robust scientific evidence for a direct link between CYP2D6 gene variants and blood sugar levels. CYP2D6 is a drug-metabolizing enzyme, primarily involved in breaking down many medications (e.g., antidepressants, beta-blockers, opioids). Some of these drugs can indirectly affect glucose metabolism, but the genetic variant itself has no proven effect on fasting glucose, insulin resistance, or diabetes risk. Claims that a CYP2D6 DNA test can inform about blood sugar are not supported by evidence and fall into the marketing category. Clinically relevant effects are only known in the context of drug metabolism – and even there, effect sizes are moderate. For blood sugar concerns, rely on established markers like HbA1c, fasting glucose, or oral glucose tolerance test, not CYP2D6 genotyping.