Cross-referencing clinical data
Vitamin B12 (Cyanocobalamin)
Vitamin B12 (Cyanocobalamin).
Strength pending.
1,000mcgDaily amount
- Category
- Vitamin
What Vitamin B12 (Cyanocobalamin) is, and what it does.
- How much to take
- 1,000mcg
About 1,000mcg a day is the studied dose.
How much to take a dayHigh confidence
Up to 250mcgA supporting amount. Helps a little, not the studied dose.
250mcg to 1,000mcgEnough for most people, and where a lot of good products land.
1,000mcg
The doseThe daily amount the trials actually used. A product at this figure is dosed right where the research is.
Above 1,000mcgMore capsules, not more effect. Rarely in a serving anyway.
Source: NIH ODS + Allen 2009 B12 review
Nothing to show here, and the reason why.
A pairing appears on this page only when a trial gave both ingredients together and measured the result. Vitamin B12 (Cyanocobalamin) has none that clears that bar.
No pairing for Vitamin B12 (Cyanocobalamin) has cleared review yet.
Stitching two separate single-ingredient studies into a pairing is the one thing this engine will not do. When a study of the combination itself holds up at source, it lands here with its citation.
No invented synergy. Where actives were studied on their own rather than together, the record shows each on its own evidence, never a combined effect no trial measured.
Research strength. Research strength says how much work stands behind the combination. It is never a product score.
Independent record. Every finding is cited to a named trial, dated, and never written by the brand.
20 pairings are live across the library today. Checked 20 July 2026.
Plays well withEstablished knowledge, not a trial
No study gave these as a pair, so they are not in the card above. But the reason they belong together is settled biochemistry, not a guess, so it is worth knowing.
Vitamin B12 (Cyanocobalamin) + MethylfolateEstablished one-carbon biochemistry. The methionine synthase reaction requires both.
Methionine synthase transfers a methyl group from 5-methyltetrahydrofolate to homocysteine using methylcobalamin as the carrier. Without adequate B12 that transfer stalls and folate accumulates in the methyl form, unable to re-enter the folate cycle. This is the methyl folate trap, and it is why the two are dosed together rather than separately.
Vitamin B12 (Cyanocobalamin) + Folic acidEstablished haematology of masked deficiency.
High folate intake corrects the enlarged red cells caused by low B12 while doing nothing for the neurological consequences, which can then progress unnoticed. This is the classic reason B12 status is checked before high-dose folate is given. The interaction is real, well documented and runs in one direction only.
Vitamin B12 (Cyanocobalamin) + Vitamin B6 (pyridoxine)Established cofactor role in the transsulfuration branch.
Homocysteine has two exits: remethylation to methionine, which needs B12 and folate, and transsulfuration to cystathionine, which needs the active form of B6. Supplying both branches addresses the metabolite from two directions. Lowering homocysteine is a biochemical marker change and not by itself an outcome.
Vitamin B12 (Cyanocobalamin) + TMG (betaine)Established alternative methyl donor route.
Betaine-homocysteine methyltransferase remethylates homocysteine using betaine as the methyl source, entirely independent of B12 and folate. It is a parallel road to the same destination, active mainly in liver and kidney. Useful as a partner, and not a substitute for B12, since the B12-dependent route serves tissues betaine cannot.
Vitamin B12 (Cyanocobalamin) + Vitamin B2 (riboflavin)Established cofactor requirement of MTHFR.
Methylenetetrahydrofolate reductase uses FAD, made from riboflavin, to generate the 5-methyltetrahydrofolate that B12 then collects. Low riboflavin throttles the supply upstream of the B12 step. The dependency is most visible in people carrying the reduced-activity MTHFR variant.
Vitamin B12 (Cyanocobalamin) + MethionineEstablished product of the B12-dependent reaction.
Methionine is the direct product of methionine synthase, the B12-dependent step, and is then activated to S-adenosylmethionine for the body's methylation reactions. B12 sits one step upstream of the methyl donor pool. Adding methionine bypasses that step without addressing the enzyme that was limiting.
Vitamin B12 (Cyanocobalamin) + SAM-eEstablished position downstream of methionine synthase.
S-adenosylmethionine is made from methionine, which is made by the B12-dependent remethylation step. Taking SAM-e supplies the end product directly and also generates homocysteine when it is used, which then needs B12 and folate to be cleared. That is the reason the two are commonly paired.
Vitamin B12 (Cyanocobalamin) + Betaine HClEstablished requirement for gastric acid in food-bound B12 release.
B12 in food is bound to protein and must be freed by stomach acid and pepsin before intrinsic factor can pick it up. People with low gastric acid absorb food-bound B12 poorly while still absorbing free crystalline B12 from a supplement normally. This is why the acid question matters for diet-derived B12 more than for the supplemental form.
Vitamin B12 (Cyanocobalamin) + CalciumEstablished calcium dependence of the ileal cubam receptor.
Uptake of the intrinsic factor-B12 complex at the ileal receptor is a calcium-dependent step. This is textbook physiology and explains why conditions that lower ileal calcium availability lower B12 uptake. It is not a reason to take extra calcium in someone already replete.
Vitamin B12 (Cyanocobalamin) + Vitamin CEstablished degradation chemistry in solution.
Ascorbic acid degrades cyanocobalamin in aqueous solution, which is a documented stability problem in liquid multivitamins and a reason the two are separated or the B12 overdosed in liquid formats. In dry capsules and tablets the effect is far smaller. This is formulation chemistry rather than a physiological antagonism.
Vitamin B12 (Cyanocobalamin) + IronEstablished shared role in red cell production.
Red cell production needs iron for haemoglobin and B12 with folate for DNA synthesis in the dividing precursor cells. A shortfall in either shows up in blood counts, and the two can coexist and mask each other's picture on a blood film. Correcting one can unmask the other.
Vitamin B12 (Cyanocobalamin) + CobaltEstablished structural chemistry.
Cobalt is the metal atom at the centre of the corrin ring, which is what makes B12 the only cobalt-containing vitamin. Humans have no use for free cobalt other than as part of a pre-formed cobalamin, since we cannot build the corrin ring ourselves. Supplementing cobalt does not produce B12 in the body.
Vitamin B12 (Cyanocobalamin) + PotassiumEstablished clinical observation during rapid repletion.
When severe B12 shortfall is corrected quickly, the burst of new red cell production draws potassium into the new cells and serum potassium can fall. This is a documented clinical monitoring point in the first days of repletion, not a general reason to add potassium. It applies to medically managed repletion, not to ordinary maintenance dosing.
Vitamin B12 (Cyanocobalamin) + Vitamin B1 (thiamine)Formulation convention in B-complex products.
B12 is supplied in B-complex products alongside thiamine because the B vitamins share dietary sources and because the group's deficiencies often overlap in the same populations. There is no direct chemical dependency between the two. The pairing is convention, and stacking a complex with a standalone B12 simply adds the doses.
Who should be cautious
Nothing specific on file for Vitamin B12 (Cyanocobalamin). Match the label to the daily amount above, and tell your doctor what you take.
Not medical advice. Show the label to your pharmacist.The forms it comes in.
CyanocobalaminCobalamin with a cyanide group in the upper axial position. It holds up better to light and heat in storage than the methyl and adenosyl forms do.Fits Fortification, long shelf-life products and routine oral dosing, and the form used in most of the trial literature.Trade-off Requires intracellular conversion to the active forms, and releases a small quantity of cyanide that the kidneys clear, which is the basis for caution in advanced kidney impairment.
MethylcobalaminThe cytosolic cofactor form, carrying a methyl group on cobalt and used directly by methionine synthase.Fits Situations where the intracellular conversion step is in question, and formulations marketed on the active-form basis.Trade-off Light-sensitive and less stable in storage, and it does not supply the mitochondrial adenosylcobalamin pool without conversion of its own.
AdenosylcobalaminThe mitochondrial cofactor form used by methylmalonyl-CoA mutase.Fits Products aiming to supply the mitochondrial pool directly, often paired with methylcobalamin.Trade-off Light-sensitive, less widely available, and the clinical literature on it is much thinner than for cyanocobalamin.
HydroxocobalaminCobalamin with a hydroxyl group on cobalt. Binds plasma proteins more tightly, giving a longer circulating retention than cyanocobalamin.Fits Injectable use, where longer retention means less frequent dosing.Trade-off Mainly a parenteral form, so it is not a like-for-like swap for an oral tablet.
Diluted cyanocobalamin blendCrystalline cyanocobalamin pre-blended onto mannitol or dicalcium phosphate so that microgram doses can be weighed accurately.Fits Manufacturing, where dosing a few micrograms of pure crystal into a tablet is not workable.Trade-off The declared potency depends on the trituration being uniform, and most of what is weighed out is carrier rather than vitamin.Formulation aid
Sublingual tablet or sprayThe same molecule in a fast-dissolving base intended for oral mucosal contact.Fits People who prefer not to swallow tablets, and those relying on passive rather than receptor-mediated uptake.Trade-off Much of a sublingual dose is swallowed regardless, so the format's advantage over an equivalent swallowed dose is not clearly separable.Active and formulation aid
Problems people have reported.
Read this carefully. These are 1,514 voluntary, unverified reactions reported to the FDA (openFDA). The number mostly reflects how popular Vitamin B12 (Cyanocobalamin) is, not how risky it is. A report is not proof Vitamin B12 (Cyanocobalamin) caused anything. It is a signal of what to watch for, nothing more.
Fatigue
70
Diarrhoea
55
Asthenia
48
Nausea
40
Rash
36
Headache
34
Source: openFDA adverse-event reports. Voluntary reporting, not an incidence rate.
FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. This information is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before starting any supplement regimen.
