Longevity Articles

The Four Types of Vitamin B12 and Their Many Benefits for Healthy Aging

The Four Types of Vitamin B12 and Their Many Benefits for Healthy Aging

Vitamin B12 is an essential micronutrient whose actions range from cellular health to cardiovascular function to cognition. While it’s found widely in animal products, middle-aged and older adults are less able to utilize vitamin B12 than when they were younger due to changes in intestinal absorption capabilities. 

As many subclinical problems of inadequate vitamin B12 intake can develop in the background without you knowing, supplementing with B12 can be a great insurance policy to support cellular, cardiovascular, and cognitive health with age.

But not all B12 supplements are created equal—let’s take a closer look at the different forms of B12 and how supplements like ProHealth Longevity’s Vitamin B12 can support healthy aging and longevity.

Forms of B12 and Why They Matter

ProHealth Longevity's Vitamin B12 is a powerful combination that utilizes the synergistic benefits of four forms of B12. This innovative formula includes the standard methylcobalamin and cyanocobalamin with the lesser-known dibencozide and hydroxycobalamin. These four forms of B12 each provide unique contributions to cellular health, energy metabolism, and longevity.

  • Dibencozide: Also known as adenosylcobalamin, dibencozide is a biologically active, coenzyme form of vitamin B12 that helps process food into energy in the mitochondria. It is also a vital component of the myelin sheath, which protects nerve cells in the central nervous system. 
    • Methylcobalamin: This is the other biologically active form of B12, which works together with dibencozide to support cellular health. Methylcobalamin is highly bioavailable and is used mainly in the liver, brain, and nervous system.
    • Hydroxycobalamin: The body readily converts hydroxycobalamin into adenosylcobalamin and methylcobalamin, which is why it’s often used in IV injections to treat severe B12 deficiencies. 
    • Cyanocobalamin: This is the most commonly used form of B12 in supplements, as it contains a (harmless) cyanide molecule that gives it stability in products and the body. 

    The type of supplement you take for vitamin B12 also matters. Vitamin B12 deficiency becomes more common as we age, as its absorption in the gut declines after age 50.

    This is because we need a protein called intrinsic factor to bind to B12 and prompt its absorption in the intestines. However, intrinsic factor production declines with age—so people with low intrinsic factor may have low vitamin B12 levels, regardless of how much they consume.

    To get around this, we can bypass intestinal absorption using lozenges, which dissolve under the tongue. This method allows a portion of vitamin B12 to be readily absorbed into the bloodstream through the oral mucosa, where it can be transported to and used by our body’s cells and tissues immediately.

    Benefits of Vitamin B12 for Healthy Aging

    Neurological Health and Cognition

    Adequate intake of vitamin B12 is known to support cognitive and neurological function. This is partly because B12 plays a critical role in the biosynthesis of neurotransmitters that regulate mood, attention, and cognition. Therefore, adequate levels of B12 help support brain health and cognitive performance.

    Another reason involves the amino acid homocysteine. During the metabolism of the amino acid methionine, homocysteine can accumulate unless the body has adequate vitamin B12 (along with folate and vitamin B6) to methylate it. An accumulation of homocysteine can have neurotoxic effects and lead to the production of free radicals, resulting in oxidative harm to cells and DNA, and compromising cognitive functions. 

    Cellular Health

    Vitamin B12 is essential for healthy cellular function and metabolism, as it acts as a coenzyme that facilitates multiple reactions. 

    We need vitamin B12 to form S-adenosylmethionine (SAMe), a methyl donor involved in the methylation of DNA, proteins, and neurotransmitters. Methylation is vital for gene regulation, protein function, and neural communication. Vitamin B12 is also integral in the Krebs cycle, where it helps convert food into energy in the form of ATP, which powers everything we do. 

    Not only does B12 contribute to energy production, but it also aids in DNA synthesis and the production of red blood cells, helping to support their function in carrying oxygen and iron to tissues. 


    Our livers do a great job of detoxifying the body, but this process can be slowed by overexposure to toxins in our diet and environment. Detoxification in the liver has two stages that work to transform and eliminate harmful molecules. The first phase uses enzymes to convert fat-soluble toxins into water-soluble intermediary compounds through oxidation. The second phase uses many nutrients, including vitamin B12, to transform those intermediary compounds into harmless compounds to be excreted. Adequate vitamin B12 intake ensures that the second phase of detoxification can be completed, reducing our overall toxic load and supporting healthy liver function with age.

    Heart Health

    High levels of homocysteine are linked to cardiovascular issues, and vitamin B12 helps to regulate them. As mentioned, vitamin B12 helps to convert homocysteine into methionine, thereby lowering homocysteine levels. 

    Key Takeaways

    • Vitamin B12 is an essential micronutrient for cellular energy production, metabolism, and detoxification, which can contribute to cardiovascular and neurological health.
    • Even when dietary vitamin B12 intake is adequate, we lose the ability to absorb and utilize it as we age. Therefore, supplemental lozenges can partly bypass digestion to increase absorption. 
    • Supplements containing the four different forms of B12 can work synergistically to support health and optimal bioavailability. 


    Clarke R, Birks J, Nexo E, et al. Low vitamin B-12 status in older adults. Am J Clin Nutr. 2007;86(5):1384-1391. 

    Stover PJ. Vitamin B12 and older adults. Curr Opin Clin Nutr Metab Care. 2010;13(1):24-27. 

    Wolffenbuttel BHR, Wouters HJCM, Heiner-Fokkema MR, van der Klauw MM. The Many Faces of Cobalamin (Vitamin B12) Deficiency. Mayo Clin Proc Innov Qual Outcomes. 2019;3(2):200-214. 

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