Can MTHFR help with weight loss?

Whether MTHFR variants directly help with weight loss is not supported by solid evidence. MTHFR encodes an enzyme involved in folate metabolism; certain polymorphisms (e.g., C677T) reduce enzyme activity and are linked to elevated homocysteine. Some commercial tests claim that impaired MTHFR slows metabolism and hinders weight loss, but the evidence is weak. No robust clinical trials show a causal effect of MTHFR variants on weight loss outcomes. Effect sizes are small, and lifestyle factors dominate. Therefore, using an MTHFR genetic test as a weight-loss tool is not evidence-based. A homocysteine blood test may be clinically relevant if deficiency is suspected, but it is not a weight-loss solution. Consumers should be cautious of marketing that overstates the role of MTHFR in body weight regulation.