Hydroxo B12 contains only hydroxocobalamin. Some other products we have, such as Active B12 5000, contains both methylcobalamin and adenosylcobalamin. Our Adeno B12, contains only adenosylcobalamin. None of our products contain the fourth form, cyanocobalamin.
Hydroxocobalamin is unique in that its structure lends itself to supporting the body's normal detoxification pathways. The other forms (Methyl and Adeno) are the primary active forms of B12 within the human body - they are both considered "coenzyme" forms, in that they are active within b-12 dependent enzymes. Hydroxo B12 is not, however it easily converts into Methyl B12 within the body. It is more bioavailable than the common supplemental form of B12, cyanocobalamin, because Hydroxo B12 (unlike Cyano B12) does not need to lose a cyanide molecule before reduction.
Methyl B12 and Adeno B12 (dibencozide) have slightly different functions within the body, with Adeno B12 primarily in cellular tissues and Methyl B12 primarily in blood plasma. Taken as supplements, the efficacy of Methyl B12 is surpassed by that of Adeno B12 in some situations and vice versa. Adeno B12 may also be easier for individuals who are sensitive to methylated B vitamins to use than the Methyl B12 form. In healthy individuals, the body is able to convert between forms. For some individuals, however, it may be harder for the body to convert from certain forms to others. The efficiency of these processes varies from person to person. Your healthcare professional should be able to administer some tests to help you determine which form is best for your individual needs. *