B12 Deficiency Symptoms: Signs, Causes and Testing
B12 deficiency symptoms include tiredness, weakness, pale skin, shortness of breath, a sore red tongue and numb or tingling hands and feet. Memory, mood and balance problems can follow, sometimes before anemia shows. Older adults, vegans, people with pernicious anemia and long-term metformin or acid reducer users face the highest risk. A blood test confirms it, with levels under 200 to 250 pg/mL usually counted as low.