Evidence check: B12 in the context of skin aging

Vitamin B12 (cobalamin) is implicated in skin aging through its roles in DNA synthesis, methylation, and antioxidant defense. Deficiency can cause hyperpigmentation, vitiligo, or premature skin aging. However, evidence for anti-aging benefits from supplementation in non-deficient individuals is weak. Mechanistic studies and some observational data suggest a link, but randomized controlled trials are lacking. Consumer DNA tests analyzing B12-related genes (e.g., MTHFR, MTRR) provide insight into methylation capacity but not direct B12 status or skin aging. Blood markers (holotranscobalamin, MMA) are more informative. The evidence level is mechanistic: biologically plausible but not clinically proven. Be cautious of marketing claims positioning B12 as an anti-aging miracle. Maintaining adequate B12 is important for overall health, but excess supplementation does not confer additional skin benefits.