NERAMIN-12 is generally used to treat and prevent vitamin B12 deficiency. Vitamin B12 supplements do help people who have a deficiency. Low levels of Vitamin B12 are more likely in people over age 50. Vitamin B12 is also more common in those with certain conditions like digestive problems and some types of anemia. Low Vitamin B12 can cause fatigue, weakness, memory loss and other problems with the nervous system.