Methylcobalamin (Vitamin B12) is a nutrient that is used for energy boosting. All B Vitamins play an important role in your body's energy production, though they don't necessary provide energy themselves, however if you are significantly deficient in B12, being supplemented will likely improve your energy level. Adequate levels of B12 is necessary to promote healthy hair, skin and nails. Low levels of Vitamin B12, can cause nail discolouration and hair changes.