At a glance
Effects
- Corrects anemia: Restores healthy red blood cell formation, reversing the anemia of B12 deficiency[1][2].
- Protects the nervous system: Maintains nerve cells and can improve neurological symptoms of deficiency such as numbness and tingling; untreated deficiency causes permanent nerve and spinal cord damage[1][6].
- Replenishes body stores: Rapidly absorbed from IM/SC injection sites, peaking within about 1 hour, with the liver as the main storage organ[8].
Vitamin (synthetic B12 / corrinoid)
Oral, IM/SC injection, intranasal
Plasma peak ~1 hour after IM injection
50–98% excreted in urine within 48h
Not controlled; OTC and prescription
About Cyanocobalamin (Vitamin B12)
Every point here is drawn from public medical and harm-reduction sources. A bracketed number after a claim — like [1]— is a reference: tap it to open the exact source it's based on (numbered list at the bottom). It is not a rating or score. Educational information, not medical advice.
Product specifics
- Est. delivery
- 3–7 business days · EU tracked
Product details as stated by the vendor (claims, not independently verified). Delivery is our standard EU estimate.
What it is
How it works
Cyanocobalamin supplies vitamin B12, which the body needs to keep nerve and blood cells healthy, make DNA, and form red blood cells[2]. After uptake the cyanide group is removed and the molecule is converted into the active coenzyme forms methylcobalamin and adenosylcobalamin[6]. Methylcobalamin acts as a cofactor converting homocysteine to methionine, while adenosylcobalamin helps convert methylmalonyl-CoA to succinyl-CoA — reactions essential for cell division and growth[6]. Because injection delivers B12 straight into the bloodstream, it bypasses the gut and works in people who cannot absorb the vitamin through the intestine[1].
Risks & side effects
Most important: The most important risk is that intensive treatment of severe megaloblastic anemia can cause hypokalemia (low blood potassium) — which has resulted in death — as new red blood cells rapidly take up potassium when the anemia corrects[7][9]. Serum potassium should be monitored and corrected before and during therapy, especially in the first 48 hours[5][9].
Common
Serious
Rare
- Severe, rapid optic nerve atrophy possibly leading to blindness in people with Leber's hereditary optic neuropathy[6][10]
- Thrombocytosis (raised platelet count) as anemia corrects[5]
- Aluminum toxicity (CNS/bone) with prolonged parenteral use in renal impairment[5]
- Fatal 'Gasping Syndrome' in premature infants from benzyl alcohol in some formulations[5]
Safety & harm reduction
- People allergic to vitamin B12, cobalamin, or cobalt[4]
- People with Leber's hereditary optic neuropathy — cyanocobalamin can cause severe rapid optic atrophy; hydroxocobalamin is an alternative[6][9]
- Caution / relative contraindication in renal impairment due to aluminum accumulation from parenteral products[5]
- Serum potassium closely during the first 48 hours when treating pernicious/megaloblastic anemia[9]
- CBC, vitamin B12, folate, iron, hematocrit and reticulocyte count before treatment[5]
- Platelet count (thrombocytosis can occur as anemia corrects)[5]
- B12 blood levels and peripheral blood counts for ~1 month[5]
- Chloramphenicol may diminish the response to vitamin B12[8]
- Colchicine and zonisamide may decrease cyanocobalamin levels/absorption[8]
- Folic acid above 10 mcg/day can mask B12-deficient megaloblastic anemia while spinal cord degeneration progresses[6]
- Avoid large amounts of alcohol during treatment[10]
- Co-administer folic acid if folate is also low — but never substitute folic acid for B12, as it can allow irreversible spinal cord damage[5][9]
- IM/SC routes are used for pernicious anemia; oral and intranasal are not adequate until hematologic remission[8]
- Pernicious anemia requires lifelong B12 — stopping causes anemia to return and irreversible nerve damage[6][9]
- An intradermal test dose is recommended in patients suspected of being sensitive[9]
Dosage context
Commonly-reported regimens (from labeling, not a prescription): a typical pernicious-anemia parenteral schedule is 100 mcg IM/SC daily for 6–7 days, then alternate days for 7 doses, then every 3–4 days for 2–3 weeks, followed by 100 mcg monthly for life[9]. An alternative is 1,000 mcg IM/SC daily for 7 days, then weekly for a month, then monthly[6]. Oral maintenance for those with normal absorption is often 1,000 mcg daily; the Nascobal nasal spray is 500 mcg in one nostril once weekly[6]. The recommended dietary intake for most adults is just 2.4 mcg/day[2]. These are clinical figures and must be set by a clinician.
Sources
- 1.MedlinePlus – Cyanocobalamin Injection
- 2.WebMD – Cyanocobalamin (Vitamin B12) oral
- 3.MedlinePlus – Cyanocobalamin (Vitamin B12)
- 4.Drugs.com – Cyanocobalamin Uses & Warnings
- 5.StatPearls (NIH) – Cyanocobalamin: Treatment & Management
- 6.StatPearls (NIH) – Cyanocobalamin / Vitamin B12 (Cobalamin)
- 7.RxList – Cyanocobalamin
- 8.DailyMed – Cyanocobalamin Injection USP label
- 9.Drugs.com – Cyanocobalamin Dosage Guide
- 10.Wikipedia – Cyanocobalamin
This information is provided for educational and harm-reduction purposes only. It is not medical advice. These substances can carry serious health risks; effects and safe use vary by individual. Consult a qualified healthcare professional before use. Legal status varies by country — it is your responsibility to know your local law. We do not encourage misuse.