Other Brands/Names

Cyanocobalamin, Arsinal, Becom-C, Becombion, Berzymplex, Bio Atp, Biocombin.

How It Works

Vitamin B12 (cobalamin) is essential for the function and development of many body systems, including the brain, nerves, and blood cells. Methylcobalamin is the active form of vitamin B12, while cyanocobalamin as the most common form of vitamin in supplements must be converted in the body to the active form.

Indications

Vitamin B12 supplements are provided for people with vitamin B12 deficiency or impaired absorption. Conditions that can lead to this include:

• Malabsorption in the gastrointestinal tract that reduces nutrient uptake, including vitamin B12.

• Chronic use of acid-reducing medicines, which can decrease vitamin B12 absorption.

• Pernicious anemia, caused by disruption of the stomach’s vitamin B12–binding protein, leading to vitamin B12 deficiency and reduced red blood cells.

• Reduced pancreatic function.

• Helicobacter pylori infection in the stomach.

• Long-term metformin therapy for diabetes that impairs vitamin B12 absorption because it can:

  • Slowing intestinal motility or;

  • Promoting overgrowth of intestinal bacteria that compete for vitamin B12.

• Small-intestinal bacterial overgrowth with excessive bacterial use of vitamin B12.

Contraindication

Vitamin B12 should not be used in individuals with a history of allergy or hypersensitivity to this supplement. Use caution in patients with kidney failure, especially when vitamin B12 is combined with aluminum-containing compounds.

Side Effects

Significant pain is a common effect after intramuscular or intravenous vitamin B12 injections, particularly in patients with thin stature. Cobalamin injections may also cause bleeding in people taking anticoagulants such as heparin.

Other frequently reported side effects of vitamin B12 include:

• Fever

• Itching or rash

• Tingling or numbness in the joints

• Shortness of breath

• Rapid weight gain

Contact a physician immediately if any of the above symptoms occur.

Types

• Tablets: 25 mcg, 50 mcg, 100 mcg.

• Injection: 500 mcg/mL in vials or ampoules; this preparation is a prescription medicine.

Dosage

Vitamin B12 is a vital nutrient. Good dietary sources include fish, shellfish, meat, eggs, and dairy products. The recommended daily intakes are:

• Infants 0–6 months: 0.4 mcg/day

• Infants 7–12 months: 0.5 mcg/day

• Children 1–3 years old: 0.9 mcg/day

• Children 4–8 years old: 1.2 mcg/day

• Children 9–13 years old: 1.8 mcg/day

• Adolescents 14–18 years old: 2.4 mcg/day

• Adults 19 years old and older: 2.4 mcg/day

• Pregnant women: 2.6 mcg/day

• Breastfeeding women: 2.8 mcg/day

Safety

Pregnancy and breastfeeding 

Vitamin B12 is considered safe during pregnancy or breastfeeding when taken at recommended doses. The suggested intake is 2.6 mcg per day during pregnancy and 2.8 mcg per day while breastfeeding. The safety of higher doses is not established.

After stent placement surgery

Avoid using the combination of vitamin B12, folic acid, and vitamin B6 after stent placement, as this supplement combination may increase the risk of blood-vessel narrowing.

Drug Interactions

• Aminosalicylic acid

Combined interaction may reduce the body’s ability to absorb vitamin B12.

• Anti-inflammatory medicines used for gout

Combined interaction may decrease vitamin B12 absorption.

• Metformin

May reduce gastrointestinal absorption of vitamin B12.

• Proton pump inhibitors (PPIs)

Interaction with omeprazole, lansoprazole, and other acid-suppressing drugs may reduce vitamin B12 absorption.

• Vitamin C Supplements

Taking vitamin B12 with vitamin C may lower vitamin B12 levels; to avoid this, take vitamin C at least two hours after a vitamin B12 supplement.

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