Deficiency: If you have a vitamin B12 deficiency you will feel tired or weak, pale skin, loss of appetite, infertility and ...

Mental clarity and focus can be affected by aging, nutrient deficiencies, and stress. A diet rich in antioxidants, vitamins, ...

including vitamin B12, the others being vitamins B1 or thiamine, B2 or riboflavin, B3 or niacin or nicotinic acid, B5 or pantothenic acid, B6 or pyridoxine, pyridoxal or pyridoxamine, B7 or biotin ...