Cyanocobalamin is a manufactured version of vitamin B12. It's used to treat and prevent vitamin B12 deficiency anaemia (when you have low levels of this vitamin in your body). It works by increasing your levels of vitamin B12.
Your body needs vitamin B12 to make red blood cells and keep your nervous system healthy. You can get vitamin B12 from your food or supplements, but sometimes there may not be enough of it in what you eat. This can happen if you eat a vegan diet or if you do not regularly eat meat, fish or dairy products.
Some conditions or treatments can stop you absorbing enough vitamin B12 from the food you eat. These include:
- pernicious anaemia
- low stomach acid due to swelling (inflammation) in the stomach lining, or certain medicines
- stomach surgery (gastrectomy)
- inflammation in your intestines because of conditions like Crohn's disease or coeliac disease
- an infection in your stomach or intestine
Cyanocobalamin comes as tablets that may be available on prescription.
It can also be given as an injection, but this is generally not available on the NHS. If your doctor prescribes vitamin B12 injections, they'll usually give you hydroxocobalamin, another type of vitamin B12.
You can also buy vitamin B12 supplements containing cyanocobalamin from pharmacies and shops. These come as tablets, capsules, mouth sprays and drops.
Key facts
- You'll usually take cyanocobalamin tablets every day to prevent or treat vitamin B12 deficiency. However, you may also need vitamin B12 injections at first to boost your levels.
- It may take a few weeks before your vitamin B12 levels and symptoms (such as extreme tiredness or lack of energy) start to improve.
- Most people do not have any side effects from cyanocobalamin tablets.
- Some people may be able to stop taking cyanocobalamin when their vitamin B12 blood levels are back to normal.
- You may have regular blood tests while taking cyanocobalamin, to monitor the levels of vitamin B12 in your blood.