• Participates in normal energy-producing metabolic processes 
• Contributes to the normal functioning of the nervous system 
• Contributes to normal homocysteine metabolism 
• Contributes to the maintenance of normal psychological function 
• Contributes to normal red blood cell production 
• Contributes to the normal functioning of the immune system 
• Helps to reduce fatigue and exhaustion
• Plays a role in cell division 

Vitamin B-12 is soluble in water and needs to be replenished daily in the form of a food or dietary supplement. It is essential for cell renewal and is especially important in the formation of red blood cells. The dose should be increased for those who are eating a high protein diet and for those who are taking birth control pills. Vitamin B-12 works best when taken with vitamin C, thiamine, riboflavin, and magnesium.