Symptoms of low Vitamin B12 can vary but often include: 1. Fatigue and Weakness: A common sign of B12 deficiency is feeling tired or weak due to decreased red blood cell production affecting oxygen transport. 2. Numbness or Tingling: B12 is crucial for nerve health, so a deficiency might cause a pins-and-needles sensation, particularly in the hands and feet. 3. Mood Changes: Low B12 levels can lead to mood disturbances, including depression and cognitive changes. 4. Memory Problems: Difficulty in concentrating or memory issues can be a symptom of B12 deficiency. 5. Physical Symptoms: These can include muscle weakness, dizziness, heart palpitations, and vision changes. 6. Gastrointestinal Issues: B12 deficiency might cause nausea, diarrhea, or loss of appetite.