Is LCT useful for skin aging?

Is the LCT gene (lactase persistence) useful for skin aging? Based on current evidence, the answer is no. LCT determines adult lactose digestion. Some direct-to-consumer companies suggest that lactose intolerance or dairy intake might influence skin aging via inflammation, but no robust human studies support this. The link between dairy and skin health is mixed; observational data show a weak association with acne, not with wrinkles or elasticity. A DNA test for LCT provides no clinically actionable information for skin aging. To slow skin aging, focus on proven interventions: sun protection, no smoking, balanced diet, and topical retinoids. LCT testing for this purpose is marketing, not evidence-based medicine. Evidence: marketing. Sources: none in provided context.