Ingredients & DescriptionThe methylcobalamin form, absorbed sublingually (under the tongue), is the most active form of vitamin B12 and is shown to have advantages over cyanocobalamin and all other forms of B12, including injections. It absorbs as readily, but keeps blood levels high. Injections provide a B12 surge, followed by a drop to a plateau level. Methylcobalamin is active immediately upon absorption as compared to cyanocobalamin that must first be converted to methylcobalamin by the body. Vitamin B12 is a water-soluble vitamin necessary for energy production; for nervous system function as it is needed to produce myelin, the fatty substance that forms a protective sheath around nerves; for the production of acetylcholine, a neurotransmitter that helps with memory and learning; for the synthesis of red blood cells; for producing the genetic materials, DNA and RNA. Vitamin B12 is primarily in animal-source foods and may be deficient in strict vegetarian diets. Vitamin B12 works with folic acid to control homocysteine levels.