Vitamin B12: Methylcobalamin vs. Cyanocobalamin

author avatar Dr. Eric Berg 03/15/2024

Pills forming B12 shape

Methylcobalamin vs. cyanocobalamin—what’s the difference between these two forms of vitamin B12, and which one is better?

Cyanocobalamin is a synthetic form of vitamin B12 that's poorly absorbed and linked to an increased risk of side effects. Methylcobalamin, on the other hand, is more potent and generally considered the better choice.

Let’s look at the differences between these two types of vitamin B12 supplements and discover how to maintain optimal vitamin B12 levels.  

What is methylcobalamin?

Methylcobalamin is a naturally occurring form of vitamin B12. This essential nutrient plays a critical role in red blood cell formation and nervous system functions while also supporting the health of nerve and brain cells.

In addition, methylcobalamin can donate its methyl group, which is crucial for DNA synthesis, neurotransmitter production, and detoxification processes. 

Because of its significance for the nervous system and brain health, methylcobalamin is frequently used in the treatment of neurological conditions, such as peripheral neuropathy and diabetic neuropathy.

Watch the video below to discover the importance of choosing the natural form of vitamin B12. 

Synthetic vs. Natural Vitamin B12

What is cyanocobalamin?

Cyanocobalamin is a synthetic version of vitamin B12 that contains a cyanide molecule. 

Because cyanocobalamin is cheap to produce, it’s typically used in vitamin B12-fortified foods and is the most commonly supplemented form of vitamin B12. 

However, cyanocobalamin has to undergo a series of complex biochemical processes to convert it into active forms of vitamin B12, such as methylcobalamin and adenosylcobalamin, that the body can utilize for cellular functions. 

Not only is cyanocobalamin poorly absorbed, but it’s also linked to an increased risk of side effects, and prolonged or excessive intake may pose potential health risks.

Cyanide blood test

Possible risks

Although cyanocobalamin contains only small concentrations of cyanide, the body has to detoxify and eliminate these potentially harmful molecules. 

This leaves individuals with poor detoxification, liver disease, or kidney issues at increased risk of cyanide toxicity.


Smokers and individuals working in mines, agriculture, and chemical manufacturing are frequently exposed to cyanide, potentially causing cyanide accumulation in the body, which could be exacerbated by taking cyanocobalamin.   

Cyanide is a toxic compound that can interfere with critical cellular functions, including oxygen transport and energy production. 

Research published in the Journal of Medical Toxicology investigated the adverse health effects of cyanide and concluded, “Low-dose exposures to cyanide frequently cause headache, dizziness, mild confusion, abdominal cramping, and nausea.”

In addition, cyanocobalamin can interact with certain medications, including antibiotics, anticonvulsants, and drugs to manage diabetes. It’s recommended to consult a healthcare professional to discuss cyanocobalamin use if you are taking prescription medications. 

Different pills on wooden spoons

Methylcobalamin versus cyanocobalamin: which is better?

While both cyanocobalamin and methylcobalamin are versions of vitamin B12, methylcobalamin is generally regarded as the superior health supplement. 

This has been confirmed by research published in Integrative Medicine evaluating the effectiveness of different forms of vitamin B12. The authors concluded that methylcobalamin is more effective than cyanocobalamin at maintaining vitamin B12 stores and preventing deficiency. 

“Not only is methylcobalamin cyanide-free, but it’s also significantly better absorbed, can immediately be utilized without the need for complex conversion processes, and is associated with a lower risk of side effects,” explains Dr. Berg. 


Bioavailability refers to how well a nutrient is absorbed and how readily the body can utilize it. 

Cyanocobalamin isn’t well absorbed, and significantly larger doses of cyanocobalamin are required to avoid vitamin B12 deficiency than methylcobalamin, which is generally readily absorbed by most people.  

In addition, a study published in Experimental and Therapeutic Medicine found that the body retains methylcobalamin at higher rates than cyanocobalamin, which is more easily excreted via urine.    

Health benefits

Methylcobalamin is the predominant form of vitamin B12 in the body and plays a crucial role in maintaining various critical physiological functions. 

Here are some of the health benefits of methylcobalamin:

  • Regulates DNA synthesis

  • Required for red blood cell formation 

  • Promotes energy production

  • Supports cognitive functions and mood regulation

  • May lower the risk of cardiovascular disease 

  • Reduces the risk of macular degeneration

  • Promotes skeletal health 

Vitamin B12 food sources

Natural sources of vitamin B12

Vitamin B12 is produced by certain beneficial bacteria residing in the gut of animals, which explains why vitamin B12 is predominantly found in animal products, leaving vegetarians and vegans at risk of vitamin B12 deficiency

Here are some of the best vitamin B12-rich food sources:

  • Meat

  • Organ meat

  • Poultry

  • Fish and seafood

  • Eggs

  • Dairy products

Nutritional yeast and certain types of algae, such as nori and spirulina, contain vitamin B12 synthesizing microbes and are among the best vegan sources of vitamin B12.  

The absorption of dietary and supplemental vitamin B12 requires adequate stomach acid and intrinsic factor, a protein that facilitates the intestinal absorption of vitamin B12. 

Factors including aging, use of antacids or diabetes medication, alcohol consumption, and gastrointestinal issues can greatly impact vitamin B12 absorption and lead to deficiency despite adequate vitamin B12 intake.

If you are concerned about your vitamin B12 status or show signs of vitamin B12 deficiency, such as anemia, memory loss, neurological issues, weakness, and fatigue, it’s crucial to consult a healthcare provider for a thorough evaluation of your health. 

Young woman taking a supplement

Key takeaways

Methylcobalamin vs. cyanocobalamin—what’s the difference, and which one is better?

Cyanocobalamin is a synthetic form of vitamin B12 supplement that’s poorly absorbed and requires conversion into active vitamin B12. 

In contrast, methylcobalamin is a naturally occurring form of vitamin B12 that’s easily absorbed and significantly more effective in maintaining adequate vitamin B12 stores than cyanocobalamin.    


1. Methylcobalamin versus cyanocobalamin: which should I take?

Methylcobalamin is generally considered the better choice as it's the active form of vitamin B12 that the body can readily absorb and utilize. 

Cyanocobalamin is a synthetic form of vitamin B12 that isn’t well absorbed and requires various biochemical conversions before it can be used for essential functions such as DNA synthesis and red blood cell production. 

2. Is methylcobalamin better than cyanocobalamin?

Yes, methylcobalamin is the superior form of vitamin B12. It’s better absorbed and more effective at maintaining optimal vitamin B12 stores than cyanocobalamin. 

3. Which type of vitamin B12 is natural?

Methylcobalamin is the natural type of vitamin B12 as it’s the predominant form in the body and naturally occurs in foods such as meat, fish, seafood, and dairy products. 

4. Who should not take methylcobalamin?

Methylcobalamin is generally considered safe if taken in appropriate dosages. 

However, individuals with chronic kidney disease, certain types of cancer, and those affected by Leber’s disease, a hereditary eye condition, should discuss the use of vitamin B12 with a healthcare provider to minimize the risk of slide effects. 

5. Is B12 cyanocobalamin good or bad for you?

While cyanocobalamin is considered safe, it does contain small amounts of cyanide, which is a potentially harmful compound that has to be detoxified and eliminated from the body. This leaves individuals with poor liver or kidney function at risk of cyanide toxicity and associated health issues. 





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