Last reviewed: October 2026 · Cleared Peptides research team
Research use only. B12 Cyanocobalamin: Research Guide is supplied for laboratory research. It is not a drug, food, cosmetic, or dietary supplement. It is not FDA-approved. It is not for human or veterinary administration. This page does not give a dose or a method of administration. A study cited on this page describes that study’s own test article. It does not make this lot an approved medicine. To check a fact, open the PubMed or DOI link, confirm the authors and year, and match the paper’s compound name, CAS number, or sequence to the specification table. The full method is on the research desk page. Identity and purity for a lot are only what that lot’s certificate of analysis reports. An HPLC percentage is not a sterility result and not an endotoxin result unless the certificate prints those tests.
Cyanocobalamin is the cyano form of vitamin B12. It is a cobalt-containing corrinoid, not a peptide. The CAS number used here is 68-19-9. Other cobalamins, such as methylcobalamin, adenosylcobalamin, and hydroxocobalamin, have different axial ligands and different CAS numbers. They are separate materials and should not be swapped without analytical checking.
| Name | Cyanocobalamin |
|---|---|
| Other names | Vitamin B12; CN-Cbl; cyanocob(III)alamin |
| CAS number | 68-19-9 |
| EC number | 200-659-6 |
| Molecular formula | C63H88CoN14O14P |
| Molecular weight | About 1,355.37 g/mol |
| Class | Cobalamin; cobalt-containing corrinoid. Not a peptide. |
| Related cobalamins | Methylcobalamin, adenosylcobalamin, and hydroxocobalamin. Different axial ligands. Do not mix their registry numbers. |
| Catalog status | Current Cleared Peptides lot: B12 Cyanocobalamin 10 mg/10 mL (10 mg in a 10 mL vial, nominal 1 mg/mL). Researcher Access Collection; sign-in required. |
Structure note
Cyanocobalamin has a cobalt(III) atom held in a corrin ring. Above and below the ring sit two axial ligands: a cyano group and a 5,6-dimethylbenzimidazole group linked through a nucleotide side chain. The cyano ligand is what separates cyanocobalamin from the other cobalamins. The three-dimensional structure was reported by Dorothy Hodgkin’s group using X-ray crystallography in 1956.
Cofactor note
In biochemistry, cobalamin cofactors are used by a small number of enzymes. Methylcobalamin is the cofactor form used by methionine synthase. Adenosylcobalamin is the form used by methylmalonyl-CoA mutase. Cyanocobalamin itself is not one of these cofactor forms; in those studies it must first lose the cyano ligand. These are biochemical roles described in the literature, not statements about a person.
Appearance, light, and handling
Cyanocobalamin solutions are red. Color is not an identity test, a concentration test, or a purity test. Cobalamins are light-sensitive, and light can convert cyanocobalamin to hydroxocobalamin in solution. Keep the vial protected from light and follow the storage and retest information on the label and lot documents. Solvent, excipients, and pH for this lot are only what the label and the lot certificate state.
Analytical testing notes for cyanocobalamin
Cyanocobalamin is identified in this guide as CAS 68-19-9, C63H88CoN14O14P. An identity test compares a measurement with those values. Cyanocobalamin has a characteristic ultraviolet-visible spectrum with absorption maxima near 278, 361, and 550 nm. Pharmacopeial identification uses the ratios between those peaks. HPLC with UV detection and mass spectrometry are also used.
Cyanocobalamin is not a peptide. The peptide-specific notes — sequence mass, 214 nm peptide-bond detection, and net peptide content — do not apply. For a solution product, the result that matters is the concentration of the stated solution, measured by the method named on the certificate. A concentration result is not a purity result, and neither is a sterility or endotoxin result.
A sterility test and an endotoxin test are not included in a chemical purity result. The compendial sterility test is a culture method (USP <71>): membrane filtration or direct inoculation into fluid thioglycollate medium and soybean-casein digest medium, incubated for 14 days. A PCR sterility screen uses a thermal cycler to detect microbial DNA and is a different method. The endotoxin test (USP <85> LAL, or USP <86> recombinant Factor C) reports endotoxin units with an incubating reader or a cartridge reader. Use a result only when that method is printed on the lot certificate. The full description of equipment, standards, and how US laboratory accreditation works is in peptide analytical testing. Lot records are on the COA page.
Frequently Asked Questions
Is cyanocobalamin a peptide?
No. It is a cobalt-containing corrinoid.
Is cyanocobalamin the same as methylcobalamin?
No. They share the corrin ring but have different axial ligands and different CAS numbers. Cyanocobalamin is CAS 68-19-9.
What does 1 mg/mL mean on this product?
It is the nominal concentration of the solution: 10 mg of cyanocobalamin in 10 mL. It is a laboratory specification, not a dose.
Does the red color confirm identity or strength?
No. Use the lot certificate and a suitable analytical method.
Is this for human use?
No. Laboratory reference only.
Selected References
Registry records and peer-reviewed literature listed as scientific background. Citation does not imply endorsement, a benefit, or any use.
- Hodgkin DC, Kamper J, Mackay M, Pickworth J, Trueblood KN, White JG. Structure of vitamin B12. Nature. 1956;178:64–66. doi:10.1038/178064a0. Cited for the crystal structure.
- Banerjee R, Ragsdale SW. The many faces of vitamin B12: catalysis by cobalamin-dependent enzymes. Annu Rev Biochem. 2003;72:209–247. doi:10.1146/annurev.biochem.72.121801.161828. Cited for the enzyme cofactor roles.
- Public records: cyanocobalamin CAS 68-19-9, EC 200-659-6. Cited to keep cyanocobalamin distinct from other cobalamins.
Research Use Only Notice
This guide is provided for educational and laboratory reference purposes. It summarizes published structural and biochemical literature. It does not describe, recommend, or imply any use in humans or animals. These materials are not drugs, foods, cosmetics, or dietary supplements on this page, are not offered here as a treatment, and no dosing or administration instructions are provided.
