Needing B12 shots more frequently

Posted , 3 users are following.

I was diagnosed with low B12 almost 2 years ago when my level was 234. I took B12 shots monthly for a few months, but noticed that the tiredness, memory issues, and tingling would come back a week before the shot was due, so my doc increased to shots every 3 weeks. All this time she tested my B12 levels every month or two, and there were in the mid-300s. Once I went on the 3-weekly shots they were around 400. The last 2-3 months  I've been feeling SO tired, very short-fused, emotional, and TERRIBLE memory. I requested my first blood test since May last week, and my numbers were down to 232 - right where they were when I was first diagnosed. And this blood test was just over 2 weeks after my last shot. So my doctor is increasing my shots to every 2 weeks, at least for the next month or two.

Also, in May of this year I was diagnosed with Anemia, although the doctors are for some reason refusing to test for IF in order to officially diagnose Pernicious Anemia. I have missed a few iron pills here and there and my iron tested low again last week. Does B12 go lower when iron is low? Strange because my iron was fine during the first year of my B12 deficiency diagnosis.


0 likes, 5 replies

Report / Delete

5 Replies

  • Posted

    Hi there, so sorry to hear about your experiences. As I understand things there is a very close link between ferritin (iron), folate ( obtained from free vegetables) and B12. Each one needs the levels of the others to be good for absorption to take place. It is always a good idea to get all these checked by a blood test, plus VitD too. It is often the case that if we are low in one, the others will be low too, and may need supplementing to get things back into balance. 

    Do you know if your folate and VitD levels are also low? It might be good to ask your doctor to check these too?

    Best wishes


    Report / Delete Reply
  • Posted

    Marion is correct, it is also important that your Folate level is monitored as this is essential to process the B12.

    There is a complex interaction between folic acid, vitamin B12 and iron. A deficiency of one may be "masked" by excess of another so the three must always be in balance.

    Symptoms of a folate deficiency can include:

    symptoms related to anaemia

    reduced sense of taste


    numbness and tingling in the feet and hands

    muscle weakness


    Folic acid works closely with vitamin B12 in making red blood cells and helps iron function properly in the body.

    It is also important to find out what is causing your B12 deficiency in the first place.

     Anyone at any age, can become B12 deficient.  However, certain people are at an elevated risk. They include the following:

    Vegetarians, vegans and people eating macrobiotic diets.

    People aged sixty and over

    People who’ve undergone any gastric and/or intestinal surgery, including bariatric surgery for weight loss purposes (Gastric bypass).

    People who regularly use proton-pump- inhibitors. H2 blockers, antacids, Metformin, and related diabetes drugs, or other medications that can interfere with B12 absorption.

    People who undergo surgeries or dental procedures involving nitrous oxide, or who use the drug recreationally.

    People with a history of eating disorders (anorexia or bulimia).

    People with a history of alcoholism.

    People with a family history of pernicious anaemia.

    People diagnosed with anaemia (including iron deficiency anaemia, sickle cell anaemia and thalassaemia).

    People with Crohn’s disease, irritable bowel syndrome, gluten enteropathy (celiac disease), or any other disease that cause malabsorption of nutrients.

    People with autoimmune disorders (especially thyroid disorders such as Hashimoto’s thyroiditis and Grave’s disease) Type 1 diabetes, vitiligo, lupus, Addison’s disease, ulcerative colitis, infertility, acquired agammaglobulinemia, or a family history of these disorders.

    Women with a history of infertility or multiple miscarriages.

    Do you see yourself among any of the above "people"?

    I am at a loss to understand why your doctor won't test you for intrinsic factor antibodies if for nothing else but to "rule out" (or rule in) Pernicious Anaemia. It could be that he knows the IFA test is unreliable in that it gives false negatives in people with PA half the time. So a negative result doesn't mean that you don't have PA. However, a positive result is a sure-fire, 95% certain indicator of PA

    Alternatively you could always ask for an MMA test. Methylmalonic acid is a chemical used up in one of the cellular reactions mediated by B12. If there's not enough B12 in the cell then MMA levels will rise. If they're not high then it means your cellular levels of B12 are OK. High levels of plasma MMA (>0.75umol/L0 )almost invariably indicate cobamalin deficiency.

    I am not a medically trained person but have had P.A for 46 years 

    Report / Delete Reply

Join this discussion or start a new one?

New discussion Reply

Report or request deletion

Thanks for your help!

We want the forums to be a useful resource for our users but it is important to remember that the forums are not moderated or reviewed by doctors and so you should not rely on opinions or advice given by other users in respect of any healthcare matters. Always speak to your doctor before acting and in cases of emergency seek appropriate medical assistance immediately. Use of the forums is subject to our Terms of Use and Privacy Policy and steps will be taken to remove posts identified as being in breach of those terms.

newnav-down newnav-up