You may not know this, but your body produces over 2 million red blood cells every second, your nerves fire thousands of electrical signals, and your DNA replicates flawlessly, all thanks to a single, tiny molecule called vitamin B12⁽¹⁾.

Unlike some nutrients the body can produce, vitamin B12 must be obtained from external sources. It's naturally made by certain bacteria and typically consumed through animal-based foods such as meat, eggs, and/or dairy or supplements.

Why Vitamin B12 Matters

Vitamin B12 is involved in crucial chemical reactions, including:

• Methylation: Through its role in methionine synthase, B12 helps regulate gene expression and DNA repair.
• Energy metabolism: Via adenosylcobalamin, B12 supports the conversion of fats and proteins into usable cellular energy.

Together, these actions are vital for cell growth, red blood cell formation, neurological health⁽⁵⁾, and much more.

Despite being essential for everything from brain function to blood formation, B12 deficiency affects millions of people worldwide, often going undiagnosed for years. As a result, it's one of the most widely recommended supplements on the market.

There are several natural forms of B12 such as methylcobalamin, adenosylcobalamin, and hydroxycobalamin, each serving distinct roles.

However, cyanocobalamin is the most widely used in supplements due to its stability, effectiveness, and ease of production. It’s the standard form used in oral tablets, injections, and nasal sprays.

Recently cyanocobalamin has become the target of viral misinformation campaigns that have people believing myths that could keep from getting the nutrition they desperately need. 

These myths include:

• It's cyanide
• Natural forms are better
• It's made from toxic chemicals
• and more

In this article we'll dispel the myths so you can make confident decisions about your supplement routine.

The name cyanocobalamin reflects its structure: a cobalt atom at the core, stabilized by a cyanide group. This trace metal is crucial for activating biochemical reactions that keep cells functioning⁽¹⁾.

Cyanocobalamin (vitamin B12) Structure

Understanding Cyanocobalamin and Its Clinical Uses

Cyanocobalamin is a synthetic version of vitamin B12. It belongs to the corrinoid family, which are comprised of compounds built around a central cobalt atom. It includes a cyanide group that keeps the structure stable for medical use. But the word 'cyanide' makes for great clickbait, so it's an easy target for misinformation. 

Although the term cyanide may sound concerning, the amount present is extremely small and safe⁽³⁾.

Here's why: Once inside the body, cyanocobalamin is converted into active forms called methylcobalamin and adenosylcobalamin. These support key reactions related to DNA repair, energy production, and nervous system health⁽⁴⁾.

FDA-Approved Uses for Cyanocobalamin

Cyanocobalamin has been FDA-approved since 1942 and is widely used to treat B12 deficiencies caused by poor absorption, dietary gaps, or certain medical conditions, as a deficiency can impair red blood cell production and damage nerves over time, leading to fatigue, cognitive problems, and other health issues⁽²⁾.

Cyanocobalamin is prescribed to treat B12 deficiency from causes including:

• Pernicious anemia: An autoimmune condition that blocks intrinsic factor production, preventing B12 absorption.
• Malabsorption syndromes: Conditions like celiac disease or Crohn’s that impair B12 uptake.
• Long-term medication use: Drugs such as metformin and acid reducers can lower B12 absorption.
• Bacterial overgrowth: Competing gut bacteria may consume or block B12.
• GI surgeries: Removal of stomach or intestinal segments can interfere with absorption.
• Infections/parasites: Organisms like H. pylori or Diphyllobothrium latum can disrupt B12 pathways.
• Pancreatic disorders: Reduced enzyme release affects B12 binding and uptake.
• Vegan diets: Lack of animal-based foods increases deficiency risk.
• Genetic conditions: Rare disorders like transcobalamin II deficiency impair cellular transport of B12.

Cyanocobalamin use in Clinical Practice

With decades of proven use, cyanocobalamin remains a trusted treatment for B12 deficiency. It’s available in oral, nasal, and injectable forms, allowing flexible administration based on severity and absorption capability⁽⁵⁾.

Symptoms of deficiency ranging from fatigue to nerve damage can be reversed or prevented with timely treatment.

How Cyanocobalamin Works in the Body

Cyanocobalamin supports energy production, DNA synthesis, and red blood cell development⁽⁶⁾.

Absorption and Transport

• Oral: Absorption requires intrinsic factor, a stomach protein.
• Injectable: Bypasses the gut, offering reliable absorption in cases of malabsorption or severe deficiency.

Once absorbed, B12 binds to transcobalamin proteins for distribution. Most is stored in the liver.

Inside the Cell

Vitamin B12 acts as a cofactor for:

• Methionine synthase (DNA repair and gene regulation)
• Methylmalonyl-CoA mutase (conversion of fats and proteins into energy)

These functions are especially critical in fast-dividing cells like those in bone marrow. Deficiency can cause megaloblastic anemia, characterized by enlarged, poorly functioning red blood cells⁽⁷⁾.

Hydroxocobalamin (another form of vitamin B12) is being studied as a possible treatment for vasoplegic shock, but more research is needed. Vasoplegic shock happens when blood vessels become too relaxed and wide, causing blood pressure to drop dangerously low. The heart keeps pumping normally or even works harder, but blood can't reach organs properly because of the widened blood vessels. This type of shock commonly occurs after serious infections, severe pancreas inflammation, or heart surgery.

Pharmacokinetics: What Happens After You Take It?

• Absorption: Rapid after injection; peaks within 1 hour.
• Distribution: Bound to transcobalamin proteins and delivered throughout the body.
• Metabolism: Converted to methylcobalamin and adenosylcobalamin in tissues.
• Elimination: Excreted mainly in urine; some reenters the gut via bile and is reabsorbed.

Benefits and Medical Uses

1. Restores B12 Levels and Prevents Deficiency

Supplementation normalizes red blood cell production, reduces fatigue, and prevents long-term complications.

2. Lowers Homocysteine

B12 helps convert homocysteine to methionine. Elevated homocysteine is linked to cardiovascular and cognitive risks. A 2022 review found B12, folate, and B6 supplementation reduced homocysteine by ~32% in people with mild cognitive impairment⁽⁸⁾.

3. Supports Mood and Mental Health

B12 aids neurotransmitter production (serotonin, dopamine, GABA). Low levels are associated with depression. A 2021 study found older adults with low B12 had a 51% higher risk of developing depression over four years⁽⁹⁾.

4. May Help Protect Brain Health

B12’s ability to lower homocysteine may reduce oxidative stress in the brain. A 2022 review suggested early supplementation could slow cognitive decline, especially when combined with other B vitamins⁽¹⁰⁾.

Dietary Sources of Vitamin B12

***Those on vegan diets should consider supplements or fortified foods to meet daily needs.

Is Vitamin B12 Safe?

B12 is extremely safe for most people (even at high doses) because excess is excreted in urine. The National Institute of Health has not set a Tolerable Upper Intake Level (UL) for B12.

Rare side effects include acne flare-ups in sensitive individuals. People with advanced kidney disease or Leber’s hereditary optic neuropathy should avoid cyanocobalamin and consult a healthcare provider.

Supplements are not tightly regulated by the FDA, so product quality can vary. Choosing reputable brands is key⁽⁵⁾.

Drug Interactions

Some medications can impair B12 absorption over time:

• Proton pump inhibitors (e.g., omeprazole)
• H2 blockers (e.g., famotidine)
• Metformin (used for diabetes)

These affect B12 from food, not supplements. Healthcare providers may monitor B12 levels for patients on long-term therapy.

Choosing a B12 Supplement

• Choose reputable brands: Look for third-party certifications (USP, NSF, UL).
• Pick the right form: Options include tablets, lozenges, liquids, nasal sprays, or injections.
• Standalone vs. combo: A solo B12 supplement is sufficient for most deficiencies.

Can You Take Too Much?

While high doses (up to 2,000 mcg/day) are sometimes prescribed, most people don't need megadoses. For best results, follow medical guidance, especially for high-dose or long-term use.

Debunking Myths

Myth 1: “It’s toxic because of cyanide.”

Reality: While it’s true that cyanocobalamin contains a cyanide group, the amount is extremely small (~20–25 micrograms per 1,000 mcg dose) which is negligible compared to everyday dietary exposure. 

For reference: A single serving of cassava, bitter almonds, or even apple seeds contain much higher levels of cyanogenic compounds than a typical B12 supplement.

Once ingested, the cyanide in cyanocobalamin is rapidly detoxified by the enzyme rhodanese (in the liver), converting cyanide into thiocyanate, which is safely excreted via the kidneys. No credible clinical data links normal doses of cyanocobalamin to systemic cyanide poisoning.

In fact, an apple contains 300,000x the cyanide of many popular energy drinks and to hit toxic levels of cyanide; you would need to consume 100-200 apple seeds at once from 20-40 apples.

Cyanocobalamin is used in clinical practice for decades and remains the most prescribed and studied form of B12 globally. As highlighted earlier, it’s also more shelf-stable and cost-effective than methylcobalamin or hydroxocobalamin, which is why it’s widely used in fortified foods and supplements.

Myth 2: “Natural forms are superior.”

Reality: It’s common to see claims that methylcobalamin (the “natural” form) is superior to cyanocobalamin, especially in marketing materials. 

However, all cobalamin forms (cyano-, methyl-, adenosyl-, and hydroxo-) ultimately convert to the active intracellular forms, methylcobalamin (for methylation) and adenosylcobalamin (for mitochondrial energy metabolism), regardless of starting form.

Key findings from comparative studies

• Cyanocobalamin has comparable efficacy to methyl- and hydroxocobalamin in treating B12 deficiency in the general population (WerePRx.com).
• A 2022 review in Nutrients concluded that for most people, there is no clinically significant difference in outcomes between B12 forms unless a rare metabolic disorder or renal condition is present⁽¹¹⁾.

Why the confusion?

Some patients with MTHFR gene variants, MMACHC mutations, or renal insufficiency may prefer methylcobalamin due to impaired conversion pathways; but this represents a small subset of the population.

Myth 3: “Cyanocobalamin is synthetic and made from toxic industrial chemicals, so it’s not natural or safe.”

The Reality: While cyanocobalamin is synthetic in the sense that it is not found in nature, it is biologically synthesized using naturally occurring bacteria through fermentation, not from toxic or hazardous industrial byproducts.

• The base vitamin B12 compound is produced by microbes such as Pseudomonas denitrificans or Propionibacterium shermanii, which naturally generate B12 analogs⁽¹²⁾.
• After fermentation, these analogs (often hydroxycobalamin) are purified and stabilized by the addition of a tiny, controlled amount of cyanide to form cyanocobalamin. The amount of cyanide used is minute and not harmful, and the body efficiently detoxifies and excretes it as thiocyanate. Importantly, the cyanide does not come from synthetic or toxic industrial sources, and the resulting compound is rigorously purified and tested for safety⁽¹⁾.
• So, while the term “synthetic” may sound concerning, the synthesis of cyanocobalamin is rooted in microbial biochemistry, not chemical factories, making this myth more about fear of the word "synthetic" than any real safety concern⁽¹⁾.
  

Myth 4: “It accumulates and is harmful.”

Reality: Cyanocobalamin is water-soluble, meaning that excess is excreted in urine. The body stores some B12 in the liver, but there's no evidence that oral or injected cyanocobalamin causes toxic accumulation in healthy individuals.

• No Tolerable Upper Intake Level (UL) has been set by the Institute of Medicine due to B12’s low toxicity profile.

Recent studies confirm, even in high-dose treatments (e.g., 1,000–2,000 mcg/day orally), there is no increased risk of mortality or adverse effects in long-term users. Elevated serum B12, when seen in labs, is more often a marker of underlying disease (like liver dysfunction or cancer), not a result of B12 supplementation.

Myth 5: “Some people have adverse reactions.” 

Reality:
 Cyanocobalamin is generally well tolerated, even at high doses. Adverse effects are rare and usually mild, including nausea, rash, or injection-site discomfort.

However, certain individuals may need alternative forms:

• Genetic defects like MMACHC mutations that affect B12 transport and conversion.
• Renal insufficiency, where hydroxocobalamin may be better tolerated
  Leber’s hereditary optic neuropathy: A rare mitochondrial disorder where cyanide processing is impaired.

In these cases, hydroxocobalamin or methylcobalamin may be more appropriate; but these are exceptions, not the rule.

Summary Chart

Final thoughts on cyanocobalamin

Many myths around its cyanide content and toxicity aren’t supported by research. Cyanocobalamin is a safe, effective, and well-studied form of vitamin B12. It supports critical metabolic processes, treats deficiencies, and poses negligible risk when used appropriately. Alternatives like methyl- or hydroxocobalamin may help in very specific cases, but for most people, cyanocobalamin remains an excellent choice.

But B12 is just one piece of the puzzle.

For you to be healthy your body needs a wide variety of essential vitamins and minerals, a strong immune system, and a healthy gut to perform its best. And that’s exactly what the Essential Stack is designed to do. Created with optimal health and the ultimate goal, it contains our daily multi-vitamin ONE+ (with 100% of your daily B12 needs and much more), Pro+FLORA Probiotic, and Vitamin C Liposomal.

The Essential Stack will help take care of the fundamentals so you can hit the ground running each day!

References:
    1.    O’Leary F, Samman S: Vitamin B12 in Health and Disease. Nutrients 2:299-316, 2010
    2.    Allen LH: How common is vitamin B-12 deficiency? Am J Clin Nutr 89:693s-6s, 2009
    3.    Elgar K: Vitamin B12: A review of clinical use and efficacy. Nutr Med J. 3:9-25, 2022
    4.    Vasavada A PP, Sanghavi DK.  : Cyanocobalamin. In: StatPearls [Internet], 2025
    5.    Stabler SP: Clinical practice. Vitamin B12 deficiency. N Engl J Med 368:149-60, 2013
    6.    Kräutler B: Biochemistry of B12-cofactors in human metabolism. Subcell Biochem 56:323-46, 2012
    7.    Wolffenbuttel BH, Owen PJ, Ward M, et al: Vitamin B(12). Bmj 383:e071725, 2023
    8.    Zhang DM, Ye JX, Mu JS, et al: Efficacy of Vitamin B Supplementation on Cognition in Elderly Patients With Cognitive-Related Diseases. J Geriatr Psychiatry Neurol 30:50-59, 2017
    9.    Murakami K, et al.: Vitamin B12 deficiency is associated with the risk of depression in older adults: A prospective cohort study. BMC Geriatrics 21, 2021
    10.    Zhou Q, Zhao, X., Wang, L., et al.: The role of homocysteine-lowering B-vitamins in preventing cognitive decline and Alzheimer’s disease: A systematic review and meta-analysis of randomized controlled trials. Journal of Alzheimer's Disease 85:203–216, 2022
    11.    O'Leary F, & Samman, S.: Oral vs. injectable vitamin B₁₂ therapy: A systematic review. Nutrients 14:1633, 2022