Vitamin B12 Injections

B12 Shots 

Vitamin B12 Injections

When are vitamin B12 injections necessary? What advantages do they have? What do the vials contain? All info on active ingredients, dosages and uses.

Vitamin B12 Injections – Tried and Tested


  • Vitamin B12 shots have been proven effective for years
  • Ideal for replenishing the body’s B12 store
  • Active ingredients vary wildly
  • For maintenance therapy, four injections in a year can be enough
  • Additives are for the most part harmless

Vitamin B12 shots are the oldest and best researched form of vitamin B12 supplements. Until as recently as a few years ago, almost all vitamin B12 deficiencies were treated by a vitamin B12 injection and they still play a major role today.

Since the majority of B12 deficiency diseases have something to do with a form of malabsorption, vitamin B12 shots are the most reliable way of ensuring you get the important vitamin: the active ingredient in the vitamin B12 shot is injected directly into the muscle and thus finds its way into the blood without needing to take the uncertain route through the digestive tract.

After a long deficiency, vitamin B12 injections are particularly useful as they represent the most reliable method of quickly replenishing the body’s B12 storage and breaking the vicious circle of deficiency. With oral supplements it is difficult to take the same quantities that are capable of slowly rebuilding the body’s natural B12 store over many months. Injections are therefore the most common method of choice for maintenance therapy.

Vitamin B12 Vials – the Different Active Ingredients

There are two types of active ingredient available for B12 shots, which the table below will compare. Cyanocobalamin is an artificial form of vitamin B12 which hardly ever occurs naturally. Hydroxocobalamin, on the other hand, is a naturally occurring form which is commonly found in many foods. Both are well researched and have proven to be very effective, but they do display clear differences:

CyanocobalaminSynthetic drug, which almost never occurs naturally in nature or in the body. Broken down in the body to methylcobalamin and the poison cyanide. The amount of cyanide is considered to be clinically irrelevant.Very affordable and very well researched. Good tolerance and effectiveness for otherwise healthy people. Not suitable for smokers. Not suitable for detoxification.
Hydroxocobalamin (also: Hydroxycobalamin)Natural form of vitamin B12, produced by microorganisms and found in foods. Must be broken down by the body for use. However, this is easier and produces no byproducts. Better intake and storage, and can also be used as an antidote to cyanide.Somewhat more expensive. Well researched. Good tolerance and effectiveness, better sustained release effect than cyanocobalamin, good for replenishing body store. Good for detoxification. Larger time period between injections required.


Vitamin B12 Shots: Hydroxocoblamin vs Cyanocobalamin

In our eyes, hydroxocobalamin clearly has advantages. In numerous studies it has been shown that hydroxocobalamin remains active in the body for much longer and is absorbed by the cells much more efficiently – meaning it rarely has to be administered. The absorption of intramuscularly administered hydroxocobalamin is around three times as high as that of cobalamin and the effect lasts considerably longer too.1,2,3,4

Vitamin B12 Injektion

Vitamin B12 injection

When you factor in the cyanide exposure through cyanocobalamin, (although the amount of cyanide released during vitamin B12 injections is clinically speaking completely irrelevant) it begs the question as to why cyanocobalamin would be chosen at all if there are such better alternatives available. Cyanocobalamin shows no positive effect when used by smokers or those suffering from disease – both of which are connected to cyanide.Hydroxocobalamin, on the other hand, has a detoxifying effect and binds to not only cyanide, but also nitric oxide.

It has also been shown that the long-term use of higher doses of cyanocobalamin leaves eight times as much biologically useless cyanocobalamin inside the body’s cells, though the consequences of that are at present unclear.6

When are Vitamin B12 Shots Necessary?

New research has clearly shown that the same therapeutic results provided by vitamin B12 injections can also be achieved through long-term oral intake of vitamin B12 in tablet or capsule form.In fact, even with a disorder of the intrinsic factor – the transport molecule which is essential for the absorption of B12 , the body can obtain enough vitamin B12 from oral doses, through passive diffusion in the small intestine.

So the question is, when is a course of vitamin B12 injections really necessary? We recommend it in the following instances:

  • If the body’s B12 storage needs to be refilled quickly
  • If shots at fixed intervals are preferred to daily pills
  • If a part of the small intestine has been removed
  • If there is a sharp parasite infection in the intestine

A further advantage of vitamin B12 cartridges is their purity: they typically contain just the active ingredient, water and sodium chloride (table salt) – and are therefore an excellent choice as an alternative to the daily intake of certain B12 pills, which contain harmful sweeteners, colourings and flavourings. However, it would also be worthwhile to consider turning to the alternative of vitamin B12 capsules or vitamin B12 sprays, which have an even higher purity in most cases.

How are Vitamin B12 Injections Administered?

Vitamin B12 is injected intramuscularly (into the muscle directly). Subcutaneous injections (under the skin) are also possible, but unpleasant. Intravenous vitamin B12 injections aren’t practiced often in vitamin B12 therapy, but are also possible.

Shots naturally entail a higher risk in application than oral supplements, and you are strongly urged to seek a referral from the doctor before taking B12 injections. Nevertheless, similarly to diabetes patients, the injection method can be properly learned under guidance from a doctor and then easily self-administered at home. It is important, however, to ensure you adhere to the required hygiene level and dispose of the shot properly after use. In addition to the syringe (cannula and needle), alcoholic wipes are required.

In any case, vitamin B12 injections remain most commonly administered by a doctor or an alternative practitioner, since many people have difficulty overcoming fear when applying their own shots and because it is easier to ensure the course is followed correctly.

What Risks are there in Taking Vitamin B12 Injections?

Vitamin B12 injections boast the same risks as all other types of injection. These are as follows:

  • A fresh cannula should be used and the point of injection should be disinfected with alcohol, otherwise contamination with germs is possible. Normally, two cannulas are used: one to fill the syringe with the solution and a second for the injection.
  • Hematoma (bruising) may occur by accidental puncturing of small blood vessels.
  • It is possible to come into contact with nerves or periosteum, causing pain.
  • When opening the glass cannulas, minute splinters of glass can end up in the solution, which can cause organ damage in the body. 8, 9

Vitamin B12 Injections – the Correct Dosage

Vitamin B12 shots are above all used to rapidly refill the body store and to ensure a healthy vitamin B12 supply for people with malabsorption and particularly anemic patients.

The therapy for these cases is conducted in two phases: first, a relatively high amount of B12 is administered for several weeks. Producers recommend 6 – 10 x 1000-1500 µg per week, in order to quickly restore B12 levels in the body storage. Thereafter, a maintenance dose is given to ensure the recommended daily intake is met (producers generally recommend 100 µg per month).

Regarding the dosage, it is however worth considering that, as a result of the aforementioned differences, the actual amount of B12 consumed is entirely dependent on the active ingredient used:

1000 µg150 – 200 µg (15-20 %)700 µg (70 %)
100 µg55 µg (55 %)70 µg (70 %)

The difference in the long term effect is equally big: whilst the serum levels in cyanocobalamin fall rapidly and the vitamin is excreted, hydroxycobalamin circulates in the body for a much longer time, because it binds loosely to proteins in the blood. So higher serum concentrations survive days and even weeks and ensures a very even supply over a long period of time.10

Based on these findings, it is our belief that slightly different proposals can be made for a vitamin B12 treatment via injections. The body’s B12 store contains around 2500 µg of vitamin B12, and the recommended daily allowance is 3 µg. Taking these numbers into account, along with the findings and recommendations of current trials, the following dosages can be recommended:

Replenishing the body store5 -8 weeks, 2 x 1000 µg per week1000 µg per week for 4 weeks or 2 x 1000 µg per week for 1-3 weeks
Maintenance therapy100 µg every 2-3 weeks or 1000 µg per month1000 µg every 3-6 months

It is clear to see the advantages that vitamin B12 shots have over oral supplements here: one injection every three months is more pleasant for most people than taking oral supplements daily.

Additives in Vitamin B12 Vials

As mentioned above, the supplements for vitamin B12 injections contain almost no additives. Here are the most common additives found in them:

Sodium chlorideAlso known as cooking or table salt, it is considered harmless, except when elevated levels of sodium or chloride in the blood occur, causing slight dehydration of the cells
Sodium hydroxide, sodium hydroxide solution (E 524)Considered harmless, also approved for baby foods and bio-products
Acetic acid (E 260)Considered harmless
Sodium acetate (E 262)Considered harmless
Hydrochloric acid (E 507)Strong acid, amounts used in medicines are considered harmless, isolated cases of negative reactions
Sodium hydrogen phosphate dihydrate (E 339)Considered harmless, consumer protection agencies warn against consumption in large doses due to phosphorous


Vitamin B12 Injections – Still a Good Alternative?

Given its high purity and the comfortable management, vitamin B12 shots represent an excellent alternative to oral vitamin B12 supplements for many people. Injections are particularly recommended in specific clinical cases of B12 deficiency because of their higher intake levels.

The option of just four shots a year without needing to constantly think about vitamin B12 intake is also an attractive proposition as a solution for vegans and vegetarians. However, from a naturopathic view, shots should be an anomaly. A daily oral supply with low levels of vitamin B12 is more natural and gentle than flooding the body with high quantities of vitamin B12 from time to time. 


1Keith Boddy, Priscilla King, L. Mervyn, A. Macleod, J.F. Adams, Retention of cyanocobalamin, hydroxocobalamin, and coenzyme B12 after parenteral administration, The Lancet, Volume 292, Issue 7570, 28 September 1968, Pages 710-712, ISSN 0140-6736,
2Glass GB, Skeggs HR, Lee DH, Jones EL, Hardy WW. Hydroxocobalamin. I. Blood levels and urinary excretion of vitamin B12 in man after a single parenteral dose of aqueous hydroxocobalamin, aqueous cyanocobalamin and cyanocobalamin zinc-tannate complex. Blood. 1961 Nov;18:511-21. PubMed PMID: 13899122.
3Begley JA, Green-Colligan PD. The availability of therapeutic hydroxocobalamin to cells. Blood. 1984 Feb;63(2):335-41. PubMed PMID: 6692038.
4Glass GBJ, et al. “Hydroxocobalamin V. Prolonged Maintenance of High Vitamin B-12 Blood Levels following a Short Course of Hydroxocobalamin Injections.” Blood, 1966, Vol. 27, No. 2, pp. 234-241.
5Hans C. Andersson, Emmanuel Shapira, Biochemical and clinical response to hydroxocobalamin versus cyanocobalamin treatment in patients with methylmalonic acidemia and homocystinuria (cblC), The Journal of Pediatrics, Volume 132, Issue 1, January 1998, Pages 121-124, ISSN 0022-3476,
6Gimsing P, Hippe E, Helleberg-Rasmussen I, et al. Cobalamin forms in plasma and tissue during treatment of vitamin B12 deficiency. Scand J Haematol 1982;29:311-318
7Andres, E., Dali-Youcef, N., Vogel, T., Serray, K. and Zimmer, J. (2009), Oral cobalamin (vitamin B12) treatment. An update. International Journal of Laboratory Hematology, 31: 1–8. doi: 10.1111/j.1751-553X.2008.01115.x
8Preston ST, Hegadoren K. Glass contamination in parenterally administered medication. J Adv Nurs. 2004 Nov;48(3):266-70. PubMed PMID: 15488040.
9Lye, S. T. and Hwang, N. C. (2003), Glass particle contamination: is it here to stay?. Anaesthesia, 58: 93–94. doi: 10.1046/j.1365-2044.2003.296812.x
10Hertz, H., Kristensen, H. P. Ø. and Hoff-JØrgensen, E. (1964), Studies on Vitamin B12 Retention Comparison of Retention Following Intramuscular Injection of Cyanocobalamin and Hydroxocobalamin. Scandinavian Journal of Haematology, 1: 5–15. doi: 10.1111/j.1600-0609.1964.tb00001.x

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