The recommended daily intake of Vitamin B12 for persons 14 years of age and older is at least 2.4 micrograms. Data from the National Health and Nutrition Examination Survey indicates the median daily intake among U.S. residents to be 3.4 micrograms.
Vitamin B12 is found in meat, fish and dairy products and essential to the proper development and function of the brain, blood cells, nerves and many other parts of the body.
Supplements taken by mouth, applied to the skin, taken through the nose or administered as a shot are likely safe for most individuals, according to the U.S. National Library of Medicine.
Vitamin B12 is often used in the prevention and treatment of B12 deficiency and pernicious anemia -more severe cases of deficiency- in older individuals.
B12 is also used to treat memory loss, boost mood, increase concentration and energy levels, strengthen the immune system, slow the aging process and treat a number of medical conditions.