If your vitamin B12 deficiency anemia is mild, you may not have symptoms or you may not notice them. Some people may think they are just the result of growing older. Symptoms develop slowly over years, as the amount of vitamin B12 absorbed by the body decreases and the vitamin B12 stored in your body is used up.

As the anemia becomes worse, you may have:^{1, 2}

• Weakness.
• Fatigue.
• Lightheadedness.
• A pale appearance.
• A sore, red tongue or bleeding gums.
• Loss of taste and appetite with weight loss.
• Diarrhea or constipation.
• A rapid heartbeat or chest pain.
• Shortness of breath upon exertion.

Low levels of vitamin B12 cause damage to the brain and nerve cells. The symptoms this causes may be the first ones you notice. They can include:²

• Numbness or tingling in the fingers and toes.
• Poor balance and coordination.
• Forgetfulness.
• Depression.
• Confusion.
• Difficulty thinking and concentrating.
• Impaired judgment and poor control of impulses.
• A decreased ability to sense vibration.
• Ringing in the ears (tinnitus).
• Dementia, a decline in mental abilities that is severe enough to interfere with daily life.