Create a healthier, happier you! Vitamin B-12 Methylcobalamin is a form of vitamin B12. This is an essential nutrient for your body to function properly and fight disease. There are several forms of vitamin B12, called cobalamins. The form that many B12 supplements use is cyanocobalamin. But the body cannot use cyanocobalamin directly. It has to transform it into activated forms, like methylcobalamin, which is the most effective for use by the cells. Vitamin B12 increases energy, improves concentration, and memory. While vitamin B12 has many benefits, some of the most notable are its ability to combat depression in the winter by treating the symptoms such as, fatigue, depression, and poor memory.