Brain Fog or B12? The Hidden Nutrient Deficiency Mimicking Memory Loss

3. Differences Between Synthetic and Natural Forms
Cyanocobalamin is the most common form found in supplements, containing a cyanide molecule. Although the amount is negligible, the body must expend energy to convert it into an active form. In contrast, Methylcobalamin is the biologically active natural form that is easily absorbed by cells and enters the metabolic cycle directly.