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Pernicious Anaemia Society
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Low b12


So I originally went to the doctors because I hadn't been feeling myself in a good 6 months. I cried constantly, lacked concentration and felt constantly tired although I have suffered with tiredness for a good 4 years, always feel run down and coldsores at least once a month. I lacked motivation, it takes all I can just to get out of bed and tidy the house - I just felt like I was lazy which made me more down. I had my contraceptive implant out as I felt that was making me worse and the doctor arranged a blood test.

The blood test came back all good except low B12 so I have just started my loading injections and then will go on to every 3 months.

My doctor wants me to go back and do a stool sample as I have suffered with heart burn and indigestion for a few months so wants to see if there is any bacteria in my stomach affecting the absorption of b12.

I have been taking vitamins as well as my Injections as I really want to feel better

Has anyone had similar experience and how did you feel after the injections ?

7 Replies

Forgot to add my levels were 90 and the doctor said they should be 150 minimum, just wondering how low this is and how long it will take to get these levels up ?


Hi Dfreddie

It is not uncommon for some symptoms to appear to get worse before they get better as the B12 starts repairing the damage done to your nervous system and your brain starts getting multiple messages from part of the body it had "forgotten about" or lost contact with.

I sometimes liken it to a badly tuned radio on which you have turned the volume up high trying to catch the programme you want when all of a sudden the signal comes in loud and clear and the blast nearly deafens you.

A lot will depend on the severity and longevity of your B12 deficiency as to how long before there is no further improvement or recovery. Some symptoms will "disappear" quite quickly whereas others may take months or even years. There is no set timescale as we are all different.

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.

I am not a medically trained person but I've had P.A. (a form of B12 deficiency) for more than 45 years.

I wish you well


Thank you so much for your informative resonse


90 is very low.

stool sample is probably about testing for H pylori infection. This is treatable so if it is h pylori then you might not need to be on maintenance shots for life.

However, heartburn suggests that the problem may actually be low stomach acidity - symptoms of which are more or less the same as high stomach acidity. This would point to PA as the most likely cause even if the test for PA comes back negative - IFA gives false negatives 40-60% of time depending on the assay method so a negative is a long way from ruling out PA as the cause.

1 like

Thank you for your resonse. I feel confident knowing what to look for or mention when I see the doctor next time about results.

Finally feel like I am getting somewhere, for so long I thought I was lazy!


I had h pylori with no stomach pain. It reduces stomach acid and therefore causes absorbtion issues of who know what all, but definiently b12 and iron.

I received 18 b12 injections with lingering general fagiue, no longer had the crushing fatigue of low b12, thank goodness, but still i wasnt well, with general fatigue, brain fog, fuzzy vision, lack of concentration and motivation.

I didnt realize my iron was low due to having a full iron panel only 24 hours after i had stopped taking iron which showed ferritin at 98 (range 15-150) and serum iron at 68 (range 27-159) with iron sat at 21% (range 15-150).

All looked good so i stopped iron, without realizing those tested my iron levels WITH the iron i was taking. You have to stop all iron for 5-7 days to get your body's unsupplimented levels.

Also what really threw me was a very good ferritin. But guess what, If you have h pylori or any other chronic infection, your body segregates iron into ferritin, away from being used by the bacteria.


Also confusing was that i would start to feel beter and then for some unknown reason, suddenly feel worse and sometimes "crash".

Finally figured out this was due to blood loss due to menstruation. I had not connected the crash/going downhill with menstration because my downhill wasnt until the second day of my period.

Almost like my body was gaining iron throughout the month and i would feel better and i would think, thank goodness. Im gonna beat this crap and then bam!!! I would feel crap again.

Not sure about your gender but menstruating ladies need more iron than men and our levels fluctuate with menstration.

Here is my point, do not let a doctor tell you your iron is good, based on ferritin levels, if you have a chronic infection!!!!

WBC raised, even if in range, could mean an infection!!! My wbc were always high but in range. Three doctors, and not a one of them ever raised any concern about wbc.


Thank you! This is something I will definitely look at when next at doctors and results are back.

I do feel like im having a veru good day somethings then the next day feel completly opposite. I'm 24 year old female but have not actually had period in 7 years due to being on contraceptive injection or implant.


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