Vitamin B12 is needed by every cell in your body. It helps make red blood cells, keeps nerves healthy, supports DNA production, and powers energy inside cells. When B12 runs low, symptoms can show up almost anywhere—tiredness, brain fog, numbness, mood changes, or worse. Deficiency is common, often missed, and can cause serious problems if ignored.

Vitamin B12, also called cobalamin, is a vital nutrient your body needs for red blood cells, nerves, DNA, and energy. It is unique because it contains cobalt (hence “cobalamin”) and is the largest, most complex vitamin. Without enough B12, cells cannot function properly, leading to fatigue, brain fog, nerve issues, anemia, and long-term health problems.

Vitamin B12 (cobalamin) is essential for red blood cell production, nerve health, DNA synthesis, and energy. Its discovery unfolded over more than 100 years, turning a once-fatal disease, pernicious anemia, into a treatable condition.

Vitamins are small organic compounds your body needs in tiny amounts to grow, repair, fight illness, and run every cell properly. You cannot make most vitamins yourself, so you must get them from food (plants or animals). Without enough vitamins, normal biochemical reactions slow down or stop, leading to fatigue, poor immunity, nerve issues, and chronic health problems.

Dietary Reference Intakes (DRIs) are the official U.S. guidelines for daily nutrient needs. They replaced the older Recommended Dietary Allowances (RDAs) and were set by the Institute of Medicine between 1997 and 2001. The goal is to provide amounts that meet the needs of 97–98% of healthy people in each age and gender group.