Medicines & Supplements A to Z > Vitamin B12

Vitamin B12

Last updated on July 3, 2019.

Overview   |   Dosage   |   Side Effects   |   Where To Buy  

GENERIC NAMES: Vitamin B12, Cyanocobalamin, Hydroxocobalamin, Mecobalamin (Methylcobalamin)


COMMON BRANDS IN HONG KONG: Vitamin B12 Sunward, Vitamin B-12 Inj Rotexmedica, Vitamin B-12 Injection Hovid , Cobamin 保視寧, Hycobal, Methocobal

What is Vitamin B12 for?

Vitamin B12 is a water-soluble vitamin that is important for our metabolic functions and the normal functioning of nerves and blood cells. Cyanocobalamin is a man-made Vitamin B12  that can be used to treat Vitamin B12 deficiency due to inadequate dietary intake. Vitamin B12  deficiency often occurs in patients with malabsorption or metabolic disorders and follow a strict vegetarian diet, which may lead to megaloblastic anemia and brain damage.   

How to use it?

Vitamin B12 can be taken by mouth or intramuscular injection. If you are taking it by mouth, the dose can range from  50-2000 micrograms daily. Higher doses (i.e. 1000-2000 micrograms) by mouth are used for people with problems absorbing Vitamin B12. If you are taking it by intramuscular injection, you should start with 1 mg every 2-3 days for 11 doses and then 1 mg every month.

What are the side effects of Vitamin B12?

Vitamin B12 has no potential side effects. If you experience side effects, tell you doctor or pharmacist immediately.

Where to buy Vitamin B12 in Hong Kong?

In Hong Kong, many types of Vitamin B12 are over-the-counter medicines and can be purchased without a prescription from any retail outlet in Hong Kong. This includes grocery stores, convenience stores, medicine shops, and pharmacies. They can also be obtained from doctors. The injection forms of Vitamin B12 are prescription only medicines and require a prescription from a doctor to be purchased in a pharmacy, or at a doctor’s clinic directly. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health. 

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at

For detailed information about the use of Vitamin B12 in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.