Vitamin B12

Vitamin B12 Uses, Dosage, Side Effects, Food Interaction and all others data.

Vitamin B12 is the neurologically active form of vitamin B12 and occurs as a water-soluble vitamin in the body. It is a cofactor in the enzyme methionine synthase, which functions to transfer methyl groups for the regeneration of methionine from homocysteine. In anaemia, it increases erythrocyte production by promoting nucleic acid synthesis in the bone marrow and by promoting maturation and division of erythrocytes.

Trade Name Vitamin B12
Generic Mecobalamin
Mecobalamin Other Names Co-methylcobalamin, MeCbl, Mecobalamin, Mecobalamina, Mecobalaminum, Methyl vitamin B12, Methyl(III)cobalamin, Methylcobalamin
Weight 250mcg/ml, 1000mcg/ml, 1 mg/ml,
Type Tablet, Injection, Oral Tablet, Extended Release, Sublingual Liquid, Sublingual Lozenge, Sublingual Tablet, Injectable Solution
Formula C63H91CoN13O14P
Weight Average: 1344.3823
Monoisotopic: 1343.587806391
Groups Approved, Investigational
Therapeutic Class Drugs for Megaloblastic Anemia
Manufacturer Health Aid Ltd, Amros Pharmaceuticals,, Rephco Pharmaceuticals Ltd
Available Country India, Pakistan, Bangladesh, United States
Last Updated: September 19, 2023 at 7:00 am
Vitamin B12
Vitamin B12


Vitamin B12 is used for-

  • Peripheral Neuropathies
  • Diabetic Neuropathy
  • Verteberal Syndrome
  • Nerve Compression Syndrome
  • Multiple sclerosis
  • Amyotrophic lateral sclerosis
  • Parkinson’s disease
  • Alzheimer’s disease
  • Diabetic retinopathy
  • Entrapment neuropathy
  • Drug induced neuropathy
  • Megaloblastic anemia due to Vitamin B12 deficiency

Vitamin B12 is also used to associated treatment for these conditions: Vitamin B12 Deficiency, Nutritional supplementation


Vitamin B12 dosage

Tablet: The usual adult dosage is one 500 mcg tablet three times daily. The dosage should be adjusted according to the age of patient and the severity of symptoms.


  • Peripheral neuropathies: The usual adult dosage is one ampoule equivalent to 500 mcg of Vitamin B12, administered intramuscularly or intravenously three times a week.The dosage should be adjusted according to the age of patient and the severity of symptoms.
  • Megaloblastic anemia: The usual adult dosage is one ampoule equivalent to 500 mcg of Vitamin B12, administered intramuscularly or intravenously three times a week. After about two months of administration, dosage should be changed to one ampoule equivalent to 500 mcg of Vitamin B12 every one to three months as maintenance therapy

Side Effects

Generally Vitamin B12 is well tolerated. However, a few side effects like GI discomfort (including anorexia, nausea or diarrhea) & rash may be seen after administration of Vitamin B12.


The medicine should not be used for months if there is no response at all after its use for a certain period of time.


Decreased GI tract absorption with neomycin, aminosalicylic acid, H2-blockers and colchicine. Reduced serum concentrations with oral contraceptives. Reduced effects in anaemia with parenteral chloramphenicol.

Food Interaction

No interactions found.

Pregnancy & Breastfeeding use

Not recommended during pregnancy & lactation.


Hypersensitivity to any component of this product.

Special Warning

Use in children: Not recommended.

Storage Condition

Oral: Store at room temperature. Protect from moisture and light.

Parenteral: Store at room temperature. Do not expose to direct light.

Innovators Monograph

You find simplified version here Vitamin B12


What is Vitamin B12 used for?

Vitamin B12 is used to treat vitamin B12 deficiency.

How safe is Vitamin B12?

Vitamin B12 is considered likely safe when used appropriately.

How does Vitamin B12 work?

Vitamin B12 works by functioning in the production of a compound called myelin, which covers and protect nerve fibers.

What are the common side effects of Vitamin B12?

Common side effects of Vitamin B12 are include:

  • Nausea.
  • Vomiting.
  • Diarrhea.
  • Loss of appetite.
  • Headache.

Is Vitamin B12 safe during pregnancy?

Pregnancy There are no data available for Vitamin B12 to be used in pregnant women.

Is Vitamin B12 safe during breastfeeding?

There are no data available for Vitamin B12 to be used in lactating women.

Can I drink alcohol with Vitamin B12?

No interactions were found between Alcohol and Vitamin B12. This does not necessarily mean no interactions exist. Always consult your healthcare provider.

Can I take Vitamin B12 daily?

The recommended dose is 500 mcg three times daily or 1500 mcg daily. Most generic vitamins contain cyanocobalamin, which may not be as effective or as beneficial.

How much Vitamin B12 should I take?

The general recommendation for adults is 2.4 mcg. Older adults, as well as pregnant and breastfeeding women, require higher doses.

Should I take Vitamin B12 on an empty stomach?

It is a well-known medical fact that water-soluble vitamins are better absorbed on an empty stomach. So, the usual time of taking Vitamin B12 will be in the morning as the first dose, half an hour before lunch, and 2 hours post a meal.

How long does Vitamin B12 take to work?

With brisk development of new red blood cells, a response is typically seen within 48 to 72 hours. Vitamin B12 supplies have reached normal levels,Vitamin B12 injections will be required every one to three months to avoid the return of symptoms.

How long does Vitamin B12 supplements stay in my system?

Other studies have shown that Vitamin B12 has a half-life of around six days in the blood, which means that it would take six days before half of the administered amount is excreted from the body

Can Vitamin B12 damage my liver?

There is no evidence that the other B vitamins, in physiologic or even super-physiologic high doses cause liver injury or jaundice.

What are the symptoms of high Vitamin B12 levels?

The study found that high doses of these Vitamin B12 were actually harmful.

Can Vitamin B12 cause kidney stones?

Vitamin B12 have not been shown to be harmful to people with kidney stones.

How long Vitamin B12 can be taken?

Vitamin B12 for 2-4 weeks is associated with better outcome in nerve conduction velocity and neuropathic symptoms.

Who should not take Vitamin B12?

You should not use Vitamin B12 if you are allergic to Vitamin B12 or cobalt. Tell your doctor if you have ever had Leber's disease or other form of optic nerve damage,an iron or folic acid deficiency.

What happens if I miss a dose of Vitamin B12?

Use Vitamin B12 as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not use two doses at one time.

Can I overdose on Vitamin B12?

You cannot overdose on Vitamin B12 because any excess you simply pee out. If you get Vitamin B12 shots, you may experience side effects like dizziness, nausea, and fatigue.

*** Taking medicines without doctor's advice can cause long-term problems.