Vitamin B12 is used in the treatment of vitamin B12 deficiency.

Vitamin B12 is a nutrient which the body requires in small amounts to make red blood cells, generate energy, and keep nerve cells healthy.

• Symptoms of Vitamin B12 Deficiency
• Weakness, tiredness, or lightheadedness
• Anemia
• Heart palpitations and shortness of breath
• Pale skin
• A smooth tongue
• Constipation, diarrhea, loss of appetite, or gas 
• Nerve problems like numbness or tingling, muscle weakness, and problems walking
• Vision loss
• Mental problems like depression, memory loss, or behavioral changes 

• Most people can prevent vitamin B12 deficiency by eating enough meat, poultry, seafood, dairy products, and eggs.
• If you don't eat animal products, or you have a medical condition that limits how well your body absorbs nutrients, you can take vitamin B12 in a multivitamin or other supplement and foods fortified with vitamin B12.