Vitamin B12 (Adenosylcobalamin)

Vitamin B12, or cobalamin, is unique among vitamins because it contains a metal ion, cobalt, from which the term cobalamin derived. Adenosylcobalamin is one of the two coenzyme forms of vitamin B12 (the other is methylcobalamin). These are the forms used in enzymes in the human body. Adenosylcobalamin is used in only one enzyme, L-methyl-malonyl-CoA mutase. This enzyme sits at a crossroads of sorts between the Krebs cycle and many amino acids. In this role, it’s important for cellular energy production and building many important molecules.*

Top Benefits of Adenosylcobalamin

Supports cellular metabolism*

Neurohacker’s Adenosylcobalamin Sourcing

Vitamin B12 can be found in different forms, including cyanocobalamin, hydroxycobalamin, adenosylcobalamin, and methylcobalamin. Adenosylcobalamin and methylcobalamin are considered to be the coenzyme forms because they are what’s used in enzymes in the body.

The adenosylcobalamin form is selected when a biologically active form of vitamin B12 is desired and the formulation’s goal is to support the Krebs cycle and cellular energy production.

Adenosylcobalamin sourcing is focused on ensuring it is non-GMO, gluten-free, and vegan.

Adenosylcobalamin Formulating Principles and Rationale

Adenosylcobalamin is dose-dependent (see Neurohacker Dosing Principles) in the range it’s commonly used (up to about 1 mg), with higher servings doing a better job in normalizing functional markers of vitamin B12 status than lower servings. The RDA for vitamin B12 is very low. Vitamin B12 function is not always maintained at these low levels, with functional status sometimes requiring substantially higher amounts to normalize [1]. Relative insufficiencies are more common with older age and in persons eating a vegetarian or vegan diet (vitamin B12 is found in animal products but not plants).*

Adenosylcobalamin Key Mechanisms

L-methyl-malonyl-CoA Mutase activity*

Adenosylcobalamin is required as a cofactor for the activity of the mitochondrial enzyme L-methyl-malonyl-CoA mutase* [2,3]

Methylmalonyl-CoA mutase converts methylmalonyl-CoA to succinyl-CoA* [2,3]

Succinyl-CoA is an intermediate of the citric acid cycle (i.e., Krebs cycle) – supports cell energy metabolism* [2,3]


Complementary ingredients*

Vitamin B6 and folic acid in supporting healthy homocysteine levels* [4–6]

Folate - Insufficient cobalamin slows the regeneration of tetrahydrofolate and traps folate in a form that is not usable by the body. This can often be corrected with higher doses of folate but can mask a vitamin B12 deficiency, so vitamin B12 is almost always given when folates are supplemented.*

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.


[1] M. H. Hill et al., A Vitamin B-12 Supplement of 500 μg/d for Eight Weeks Does Not Normalize Urinary Methylmalonic Acid or Other Biomarkers of Vitamin B-12 Status in Elderly People with Moderately Poor Vitamin B-12 Status. The Journal of Nutrition. 143 (2013), pp. 142–147.
[2] F. O’Leary, S. Samman, Nutrients. 2, 299–316 (2010).
[3] J. M. Berg, J. L. Tymoczko, G. J. Gatto, L. Stryer, Eds., Biochemistry (W.H. Freeman and Company, 8th ed., 2015).
[4] J. Selhub, Annu. Rev. Nutr. 19, 217–246 (1999).
[5] E. Lonn et al., N. Engl. J. Med. 354, 1567–1577 (2006).
[6] D. Serapinas et al., Reprod. Toxicol. 72, 159–163 (2017).