What you Need to Know about B12 Injections

Here’s a Q&A I put together about B12 injections and oral supplements.  It will answer most of your questions about B12 deficiencies but as always never use the internet as your doctor!  Confirm everything with your medical professional.  

The answers here are the very short version of some studies and medical websites on the web.  If you need more in-depth information please search the internet and be sure the source is credible.

What does a shot of B12 do for you?

Vitamin B12 is a widespread vitamin deficiency.  A B12 injection is a drug called Cyanocobalamin (cobalt)  and it is used to treat low levels of vitamin B12. B12 is needed to process body fat and carbohydrates into energy.  Vitamin B12 also makes new protein.  It is important for red blood cells, nerves, and brain function.  Low B12 has been linked to osteoporosis. There may be some evidence that adequate levels of this vitamin can reduce the incidence of macular degeneration. 

B12 is crucial for women who want to get pregnant. It can help prevent birth defects and is crucial in the early stages of pregnancy.  Low levels of B12 were linked to a three-fold increase in birth defects.

If you don’t want an injection it is possible to take vitamin B12 tablets but there is some concern over the absorption of tablets if you have had stomach surgery (bypass), Crohn’s disease, celiac disease, bacterial growth, or a parasite.  It would be best to consult your physician regarding ways to get enough B12 in your system.

What are the symptoms of vitamin B12 deficiency needing B12 injections?

Symptoms of needing vitamin B12 in your system are very subtle. You may simply feel fatigued. You may feel depressed.  If you feel tingling in your hands and feet or memory loss you should see your doctor and if you are vegan or vegetarian let your doctor know that as well.  Diagnosis may be quicker with more information for your doctor. 

Severe deficiencies and vitamin B12 can lead to megaloblastic anemia.

You may have megaloblastic anemia if you experience the following symptoms

  •  shortness of breath
  •  headache
  •  heart palpitations
  •  fatigue
  •  poor balance
  •  memory loss

Is it worth getting a B12 shot?

Getting a B12 injection may be important if your doctor deems it necessary to do so. Vitamin B12 injections are only given by prescription. In order to get B12 injections, you should be diagnosed with a vitamin B12 deficiency. A substantial B12 deficiency can be serious and lead to problems mentioned elsewhere in this article.

Vitamin B12 injections are quickly absorbed and work within 48 to 72 hours and start to help form red blood cells almost immediately.

Vitamin B12 injections seem to have a wide range in price. From my research, I believe that most injections will cost $100 to $150 (US data).  If you live outside of the USA don’t let these prices scare you.  In Canada for instance you can obtain a vile of B12 for about $40 or about $10 per shot.  

Why do I have a B12 deficiency?

  • You may be a vegan or vegetarian who does not get enough B12 in your diet.
  • You may have had stomach or bowel surgery and B12 is less able to be absorbed
  • You suffer an immune disease like HIV or lupus
  • You use alcohol in large quantities (possible abuse) 
  • You may be taking medication for heartburn.
  • As you age you may be more likely to supplement B12 with injections. 

How long does a B12 shot last?

This is a hard question to answer.  Each credible source that I have reviewed seems to say something different.  Depending on the source (which drug) of B12 it may be between one and three months. 

There are other websites that say weekly to ten days.  One factor that most authors have mentioned is that it depends on your health condition, your diet, and supplementation.   

Do B12 shots give you energy?

There have been some unsubstantiated claims that extra energy and weight loss may be a byproduct of B12 injections.   There has been no evidence to back up these claims. 

Having said that people having a severe B12 deficiency might receive an energy boost once treatment begins. 

Does B12 make you gain weight?

There is no evidence correlating vitamin B12 to weight gain.

Will B12 help me lose weight?

My research on Healthline found a small study where 256 children had with lower levels of B12 tended to have a higher body mass index(BMI)

The study did not take into consideration other factors that may be associated with body weight so it can’t be concluded that vitamin B12 helps with weight loss. There needs to be more research on this topic before we can give a definitive answer.

Does B12 help with anxiety?

A B complex vitamin can help with anxiety in some people.  It really depends on what is causing your mood issue.  B5 helps with adrenal glands which can reduce anxiety, B6 helps with mood regulation and B12 may help with depressive moods.  

What are the side effects of B12 injections?

Most often there are no side effects or some reddening around the injection site.  There is, however, the possibility of headaches, nausea, vomiting, or diarrhea.  You may also feel fatigued, suffer some weakness, or have tingling in your hands and feet.  If you suffer from any side effects you should contact your physician.

What is the best vitamin for stress and anxiety?

The National Library for Medicine Indicates that B12 levels were largely unaffected.  The B vitamins can be affected by stress and exercise and it is important, especially with hard exercise that enough B complex vitamins are taken.

How much B12 does a man or woman need?

Daily doses of B12 are measured in micrograms.  Most adults need about 2.4 mcg but if you are breastfeeding your will need to up that amount to 2.8 mcg. 

Can you take too much vitamin B12?

While B12 is considered very safe you should never try to administer megadoses to yourself.  Your body will generally excrete excess B12 in your urine.  Megadoses of injectable B12 have been linked to acne and puss-filled bumps associated with rosacea. 

There is some evidence that large doses of B12 are associated with kidney problems in diabetics and a greater risk of heart disease and stroke.  

Too much B12 during pregnancy may lead to autism in your child.  

If you are supplementing B12 consider 500mcg or less.  There are many tablets on the market offering 1000mcg or more per pill.  Again, see your doctor if you think you need a megadose of B12.  

Who should not take B12 injections?

If you have a B12 allergy, Leber’s disease, kidney or liver disease, infections, drugs that affect bone marrow, and iron or folic acid deficiency discuss your treatment options with your physician before getting your B12 injection.

So there you have it.  I recommend further reading as well.  Healthline and WebMD are two excellent sources of information along with other physicians’ websites.  

Look for more articles on vitamins and vegan/vegetarian requirements as I continue my research.