A large number of patients undergoing bariatric surgery are deficient in copper, and Roux-en-Y gastric bypass can further aggravate it. Delays in diagnosis and treatment of copper deficiency can leave patients with residual neurological disability. This has led to recommendation from the British Obesity and Metabolic Surgery Society that copper levels should be monitored annually after gastric bypass. This review concludes that copper deficiency in adequately supplemented patients is rare and can be adequately treated if a related haematological or neurological disorder is diagnosed. The cost of routine monitoring may therefore not be justified for adequately supplemented, asymptomatic patients who have undergone Roux-en-Y gastric bypass. The screening may however be necessary for high-risk patient groups to prevent severe complications and permanent disability.