While finding out you have a B12 deficiency can be both unsettling and worrying, it’s important to know that, correct and timely B12 treatment can mean reversal of all of your symptoms. You can rebuild that protective myelin sheath and live life feeling well again with the right frequency and the right kind of treatment for you. 

There are different forms of B12 and different deliveries…

Hydroxocobalamin injections

Hydroxocobalamin injections are used to treat B12 deficiency by the NHS in the UK. This is a very stable form of B12 and is converted to methylcobalamin and adenosylcobalamin in the body.

In the UK, injectable B12 is only available on prescription. If B12 deficiency is caused by a malabsorption issue and not dietary lack, injections will be required for life. Once diagnosed, treatment in the UK is defined by NICE and BNF Guidance, however this guidance incorrectly assumes we are all the same with the same level of need. New Guidance is due to be discussed so hopefully this will be properly addressed.

NICE states that firstly a loading dose; intramuscular B12 injections of hydroxocobalamin should be given every other day for two weeks.
This frequency should continue for patients with neurological involvement, until all symptoms stop improving.

This should then be followed by lifelong maintenance doses of hydroxocobalamin at two-monthly intervals. But what about those without neurological symptoms? Well unfortunately, you are allowed a loading dose and then one injection every three months. Many cannot cope on the restricted ‘maintenance’ regimes and they are not based on clinical evidence, they came about as a result of cost saving exercises. The petition to make B12 injections available to buy from pharmacies in the UK continues. 

Please note: There is no known toxicity of B12, it has been in safe use for over 60 years. B12 it is used in huge quantities as a treatment for cyanide poisoning. 


Injectable cyanocobalamin is commonly used in the US and Canada and some European countries. This form converts to hydroxocobalamin and then to methylcobalamin and adenosylcobalamin in the body. It is a very stable form but is considered inferior to hydroxocobalamin and it can worsen Leber’s optic atrophy. It is advised that smokers do not use cyanocobalamin.

Oral cyanocobalamin is a supplement in tablet form. They are suitable only for the small number of people with proven dietary deficiency of vitamin B12. See this BMJ article for more info. 

Please note: Those of you in the US should be able to access hydroxocobalamin via prescription from both CVS and Walgreens pharmacies.

Methylcobalamin & Adenosylcobalamin

Methylcobalamin is available in injection form in the UK from private doctors or available over the counter in the form of sublingual lozenges, capsules, sublingual sprays, nasal sprays and patches. It’s important to note that these supplements will not be effective treatment for everyone.

Adenosylcobalamin is another form of active B12 which can also be used in injection form but is more commonly used in sublingual lozenges, as liquid drops or in powder form.

Please note: we are all different and we may respond differently to the individual forms of B12. Some patients might require a combination of forms and quantity and frequency for optimal treatment.


Folate is a key co-factor to B12 and is very often low when B12 deficiency is found. Please see the folate page for more information. It is also wise to take a good vitamin B complex in addition to your B12 injection as all B vitamins need each other to work properly. Supplementing one in isolation can cause an imbalance in others. 

Want a better way to monitor your treatment and keep all your vital B12 information in one place? Then take a look at our app, ready to download now – available on IOS and Android.

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