Pernicious Anaemia Society
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Absorption issues?


I was detected as B12 deficient when I had burning sensation in my hands, arms and shoulder blades. Fortunately, my doctor asked me get my serum B12 checked when I told him my symptoms. So on 18th Jan 2018, when I got it tested, the level was "206 pg/ml". As per him, I should at least have 500-600. He then started me on injections and I got 10 of them over 5 weeks. So my injections stopped on 19th Feb 2018 and then on 24th Feb, out of curiosity, I got my levels tested which came back as "1710 pg/ml". This was post 10 jabs of methylcobalamin of 1500 mcg each.

Now, he asked me to continue on tablets of 1500 mcg along with few other vitamins for couple of months. I took a tablet everyday for 60 days and then got my levels checked to make sure that I do NOT have absorption issues. This time on 24th Apr 2018, my level was "1830 pg/ml".

Many of my symptoms went away in last 4 months. Some came back for a day after 2 months of gap and then again went away.

I now have a concern: Does the high level of serum B12 indicate issue of absorption of B12 at Cell level? Following is the summary of levels:

18th Jan 2018: 206 pg/ml

24th Feb 2018: 1710 pg/ml (Post 10 injections of 1500 mcg)

24th Apr 2018: 1830 pg/ml (Post consuming 1500 mcg tablet everyday for 60 days)

What do you guys think?

3 Replies

The high levels mean that you don’t have an absorption problem, so no need for further injections. They also mean that you don’t need to take such high doses.

A level of 500 to 600 ng/L is quite a bit above the normal amount. About 80% of the normal population have levels lower than this.

So I would start dropping the number of tablets you take, just to save a bit of money.

Are you vegetarian? Because that’s the most common reason to have a B12 deficiency with no absorption problems.

1 like

Yes, I am a vegeterian but eat 2-3 eggs per quarter, lol.

Till onset of this deficiency, I had NO, absolutely no issues whatsoever. Just one fine day, I started having burning sensation in arms, shuolder blades and hands. Slowly tiredness set in too.

The fatigue took 2 months to resolve which I think is due to production of new healthy RBC coz of B12.

One mystery is that, at times I get numb fingers (2-3 times in a month) and burning arms (once in 2 months). Is this normal? I thought once its gone, its gone. When such symptoms set in, I get depressed that even after so much of B12 in my blood, why am I getting it back. Fortunately, the symptoms dont last long and go on their own in a day or two.


From what I've read, people absorb roughly 1% if the b12 in tablets even with an absorption problem. That's why the tablets have to be so strong. Perhaps you absorbed around 15 mcg from each tablet, which is actually six times the normal daily requirement, so it's no surprise the serum value was high afterwards. But you may still have an absorption problem in the sense that you wouldn't absorb enough from food alone. I'm not a professional, I'm just sharing my personal understanding.

I think it's very important to understand how little of the tablets is absorbed, but if they're strong enough they still seem to work for some people. A 1000 mcg tablet should perhaps be thought of as roughly a 10 mcg tablet, in terms of uptake rather than intake. And a 1500 mcg tablet as approx.15 mcg, and so on.

BTW, milk is a good source of b12 in case you're lactovegetarian. 300 ml contains around 2.8 mcg which is more than the daily requirement.


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