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Vitamin B12 (Cyanocobalamin)

Most stable and researched form of vitamin B12, requiring conversion to active forms in the body

Scientific nameCyanocobalamin FormulaC63H88CoN14O14P Molecular weight1355.37 g/mol CAS68-19-9
70 absorption score
9 safety / 10
8 USD per month
6 documented interactions

Check it against something

Evidence level A

Vitamin B12 (Cyanocobalamin) with:

Compatibility score 99 out of 100
99 out of 100
Works better together Take together — same timing window amplifies the synergy.

Check it against your whole stack →

What it does

mechanism and evidence for each claim

Energy production support

Essential cofactor in cellular energy metabolism

Converted to active forms for mitochondrial function Evidence A-grade 2-4 weeks

Neurological function

Maintains myelin sheath and nerve conduction

Converted to methylcobalamin and adenosylcobalamin Evidence A-grade 4-12 weeks

Red blood cell formation

Prevents megaloblastic anemia

Required for DNA synthesis in rapidly dividing cells Evidence A-grade 6-8 weeks

Cognitive function

Supports memory, focus, and mental clarity

Methylation processes and myelin maintenance Evidence B-grade 4-8 weeks

Mood regulation

Supports synthesis of mood-regulating neurotransmitters

Methylation pathways for serotonin and dopamine Evidence B-grade 4-12 weeks

Others take these for the same thing

Same goal, different mechanism — check any of them against this one

Ashwagandha Stress management & energy 300-600mg A 75% Coenzyme Q10 (CoQ10) Heart health & cellular energy 100-200mg A 10% Fish Oil (EPA/DHA) Heart & brain health 1-2g EPA/DHA A 85% Phosphorus Bone health & energy metabolism 700-1250mg A 80% Vitamin B3 (Niacinamide) Energy & skin health (no flush) 100-1000 mg A 88% L-Theanine Calm focus & stress relief 100-400mg B 90%

Or a different form of the same thing

the comparison people search most
Vitamin B12 (Cyanocobalamin) vs Vitamin B12 (Methylcobalamin) absorption 70 against 85 · $8 against $15 a month 85% Vitamin B12 (Cyanocobalamin) vs Vitamin B12 (Hydroxocobalamin) absorption 70 against 75 · $8 against $35 a month 75% Vitamin B12 (Cyanocobalamin) vs Vitamin B12 (Adenosylcobalamin) absorption 70 against 80 · $8 against $60 a month 80%

All Vitamin B12 forms ranked by absorption →

Every pair we checked

12 combinations scored by the engine
Vitamin B12 (Cyanocobalamin) + Caffeine No documented interaction either way No known interaction 70
Vitamin B12 (Cyanocobalamin) + Creatine Monohydrate No documented interaction either way No known interaction 70
Vitamin B12 (Cyanocobalamin) + Whey Protein No documented interaction either way No known interaction 70
Vitamin B12 (Cyanocobalamin) + Turmeric No documented interaction either way No known interaction 70
Vitamin B12 (Cyanocobalamin) + Lactase Improved calcium absorption when consuming dairy Works better together 82
Vitamin B12 (Cyanocobalamin) + Bovine Collagen Essential for collagen synthesis and cross-linking Works better together 82
Vitamin B12 (Cyanocobalamin) + DHA Prevents oxidation of DHA and enhances stability Works better together 82
Vitamin B12 (Cyanocobalamin) + Betaine HCl Alternative methylation pathway support Works better together 86
Vitamin B12 (Cyanocobalamin) + Vitamin D3 Both involved in homocysteine metabolism Works better together 90
Vitamin B12 (Cyanocobalamin) + Fish Oil (EPA/DHA) Protects fish oil from oxidation Works better together 90
Vitamin B12 (Cyanocobalamin) + Calcium Carbonate Essential for calcium absorption and utilization Works better together 94
Vitamin B12 (Cyanocobalamin) + Folate (5-MTHF) Work together in methylation and DNA synthesis Works better together 99

Dosage

Morning with food
Daily250-1000 mcg
Maintenance250-500 mcg
Therapeutic1000-5000 mcg
MaximumNo established upper limit
Injection equivalent1000 mcg oral = 100 mcg injection

Before you take it

VeganYes

When to expect it

First Effects1-2 weeks for energy improvements
Peak Benefits8-12 weeks for neurological and cognitive benefits
Deficiency Development3-5 years with no intake (due to liver stores)
Toxicity OnsetNo known toxicity at any dose

How to measure it

$60-120 for both tests
MarkerSerum B12 and MMA (methylmalonic acid)
OptimalB12: 400-900 pg/mL, MMA: <0.4 μmol/L
Deficient belowB12: <200 pg/mL, MMA: >0.4 μmol/L
FrequencyAnnually for vegans, every 2-3 years for others over 50

What people actually reported to the FDA

CAERS, 61 reports naming it as the suspect

Most reported effects

Malaise 9
Nausea 7
Pruritus 6
Urticaria 6
Dizziness 6
Named as the suspect 61 reports of 641 that mention it at all
Serious outcome 80% hospitalisation, emergency room or worse
Other Serious or Important Medical Event40
Hospitalization13
Visited Emergency Room11

Reports are voluntary and unverified — they record what someone experienced while taking something, not what the compound caused. Counts skew towards products people take a lot of, and a serious outcome is more likely to be reported than a mild one, so these are not rates. How we filter them →

What actually reaches you

The label counts the carrier, your body does not
Absorption High 70 of 100 · absorbs well relative to other forms
Delivered daily 0.4 mg
Cost per 10 mg delivered $6.10 comparative — uses the absorption score, not a measured percentage

Works better with

3 documented
+
Folate

Work together in methylation and DNA synthesis

Complementary roles in one-carbon metabolism · level A
+
Vitamin B6

Both involved in homocysteine metabolism

Sequential steps in methylation pathway · level A
+
Betaine

Alternative methylation pathway support

Provides methyl groups for homocysteine conversion · level B

What not to take with Vitamin B12 (Cyanocobalamin)

3 documented
!
Vitamin C Megadoses

Very high vitamin C may destroy B12

Oxidative destruction in supplements · mild significance
!
Alcohol

Chronic alcohol use depletes B12

Impaired absorption and increased excretion · moderate significance
!
Smoking

May impair cyanocobalamin conversion

Increased cyanide load affects conversion enzymes · mild significance

Medication interactions

Discuss these with a pharmacist before combining
metformin Moderate

Reduces B12 absorption

What to do: Regular B12 monitoring and supplementation

proton-pump-inhibitors Moderate

Reduces B12 absorption from food

What to do: Consider B12 supplementation with long-term use

nitrous-oxide Major

Inactivates B12 and can cause deficiency

What to do: Avoid recreational use, monitor if medical use

Available forms

bioavailability compared

Ranks 4 of 4 among vitamin b12 forms. Vitamin B12 (Methylcobalamin) absorbs better — 85%. Compare all forms →

Cyanocobalamin 70

Cyanocobalamin: Most stable, Least expensive, Most research, Long shelf life

Food sources

before you supplement
Clams 84 mcg/100g · 90
Beef liver 70 mcg/100g · 85
Nutritional yeast (fortified) 17 mcg/100g · 80
Salmon 4.9 mcg/100g · 75
Fortified cereals 6.0 mcg/100g · 70

Too little

deficiency signs
  • Fatigue and weakness
  • Megaloblastic anemia
  • Neurological problems (tingling, numbness)
  • Memory problems and cognitive decline
  • Depression and mood changes
  • Balance problems and difficulty walking
  • Glossitis (smooth, red tongue)

Too much

toxicity signs
  • No known toxicity symptoms
  • Possible acne flare-ups at very high doses
  • Rare allergic reactions
  • No upper limit established
  • Water-soluble, excess is excreted

Who benefits most

vegans-vegetarians

B12 is found almost exclusively in animal products

250-1000 mcg daily
elderly-over-50

Reduced stomach acid and intrinsic factor production

500-1000 mcg daily
budget-conscious

Most cost-effective form of B12

250-1000 mcg daily
pernicious-anemia

Autoimmune condition affecting B12 absorption

1000-5000 mcg daily or injections
metformin-users

Metformin reduces B12 absorption

500-1000 mcg daily

Where to buy it

compare forms first

Look for Vitamin B12 (Cyanocobalamin) at 250-1000 mcg per serving. The form that matters here is Cyanocobalamin.

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What else affects it

Beyond other supplements
!
Alcohol

Chronic alcohol use depletes B12

Impaired absorption and increased excretion
!
Smoking

May impair cyanocobalamin conversion

Increased cyanide load affects conversion enzymes

How it works

  • Converted to methylcobalamin for methylation reactions
  • Converted to adenosylcobalamin for mitochondrial function
  • Essential for DNA synthesis and cell division
  • Required for myelin sheath formation and maintenance
  • Supports homocysteine to methionine conversion
  • Critical for red blood cell maturation

Key findings

what the evidence supports
  • Essential for preventing megaloblastic anemia (established)
  • Most stable form with longest shelf life
  • Used in majority of B12 clinical trials
  • Effective for treating B12 deficiency (Cochrane 2018)

Sources: NIH Examine.com · data reviewed 2026-08-02

Compiled by Denis, who maintains this database and holds no medical qualification — every figure here is sourced or derived, never asserted. How we calculate it →

Common questions

What are the benefits of Vitamin B12 (Cyanocobalamin)?

Documented effects: Energy production support; Neurological function; Red blood cell formation; Cognitive function. Essential cofactor in cellular energy metabolism

How much Vitamin B12 (Cyanocobalamin) should you take per day?

The common daily range is 250-1000 mcg. By goal — maintenance: 250-500 mcg; therapeutic: 1000-5000 mcg; maximum: No established upper limit; injection equivalent: 1000 mcg oral = 100 mcg injection.

When is the best time to take Vitamin B12 (Cyanocobalamin)?

Morning with food. First effects are typically reported within 1-2 weeks for energy improvements.

What are the side effects of Vitamin B12 (Cyanocobalamin)?

At excessive doses: No known toxicity symptoms, Possible acne flare-ups at very high doses, Rare allergic reactions, No upper limit established, Water-soluble, excess is excreted. Safety rating at normal doses is 9 out of 10.

What should you not take with Vitamin B12 (Cyanocobalamin)?

Separate it from Vitamin C Megadoses, Alcohol, Smoking by two to four hours. Very high vitamin C may destroy B12

Does Vitamin B12 (Cyanocobalamin) interact with medications?

Documented interactions with metformin, proton-pump-inhibitors, nitrous-oxide. Discuss these with a pharmacist before combining.

How do you know if you need Vitamin B12 (Cyanocobalamin)?

The marker is Serum B12 and MMA (methylmalonic acid), optimal range B12: 400-900 pg/mL, MMA: <0.4 μmol/L. Common deficiency signs: Fatigue and weakness, Megaloblastic anemia, Neurological problems (tingling, numbness), Memory problems and cognitive decline.

Taken for

52 Brain & Focus

Caffeine · DHA · Fish Oil (EPA/DHA)

 62 Energy & Metabolism

Vitamin B12 (Methylcobalamin) · Ashwagandha · Vitamin B12 (Cyanocobalamin)