b12 depletion rate: At the end of... - Pernicious Anaemi...

Pernicious Anaemia Society
22,338 members15,768 posts

b12 depletion rate


At the end of October my serum b12 was >2000

I had loading jabs which finished on 23rd Sept, I followed this with 5000 strength sublinguals until the end of Oct and stopped them as they didn't agree with me.

Since then I have just taken a few 1000 strength sublinguals.

Today my b12 is 754, my question is this.

In app 7weeks my b12 level has dropped from above 2000 to 754, is this a normal depletion rate ? no diagnosis of pa as yet, currently undergoing neurological tests etc.

I have kept my folate levels up by supplementing, 12 in Oct, 15 today.

5 Replies

Regarding the 5000 mcg sublinguals, when you write "they didn't agree with me", what symptoms were you having?

The drop is on an exponential decay curve that drops off fast initially and then plateaus out to a gradually dropping slope.

Stress and worry consume lots of B12 and you use it up faster.

in reply to pvanderaa

They caused heart palpitations and body overheating at night, also very red face and chest, could have forced blood pressure up maybe ??

in reply to Kenbowns

My blood pressure actually dropped when I got on B12.

How long did the heart palpitations, the sweats and red face last?

For me it was the repair of the vagus nerve that gives me all sorts of stomach issues and ravenous hunger. This still happens occasionally and, if I remember it is the day of my jab, I can tell myself that the hunger is an illusion from the repair of the nerve and can, in most part, ignore the hunger pangs.

I also get issues from too much folic acid. Thumping is my ears like high blood pressure.

The stronger these symptoms from B12 are, the more you needed the B12 in the first place. Once you have enough B12, this overreaction of you body goes away until you become deficient again.

Getting past these symptoms is the hard part but if you can convince yourself they are only temporary you can relax and gain some control back and they go away fast.

Elimination of B12 from the blood doesn't follow an exponential curve, it's a bit more complicated than that.

B12 in the blood will bind to 2 proteins - HC and TC. Anything not bound to these proteins will get filtered out in the kidneys, but a portion of that will get reabsorbed. There is a fixed limit on how much can get reabsorbed - the rest goes out in the urine.

So anything above this reabsorption limit gets eliminated almost as soon as it gets into the blood and the blood level drops very quickly - in a linear fashion. Soo the blood level drops to the point where almost all of that filtered out gets reabsorbed and the blood level stops dropping so fast.

What happens next depends on masses of factors. Some of the B12 will be eliminated from the liver into the small intestine, via the bile. If there's any IF (intrinsic factor) there then the B12 can be reabsorbed. If there isn't then it can't and it's gone for good. If you have a bacterial overgrowth in the small intestine (where bugs from the large intestine move up to where they're not wanted) then they can grab the B12 before it can get absorbed - If or no IF.

There are also differences in the efficiency of recycling B12 after it's been used in reactions.

The rate at which B12 is used up, after emergency repair to damaged nerves and replacement of red cells, is fairly constant and is not grossly affected by things like stress.

So people can vary quite a bit in how B12 levels drop after the initial plummet. I wouldn't worry about it dropping from over 2000 to 750 over 7 weeks as much of that would be the initial drop. Besides, as we keep saying - it's the symptoms that matter, not the numbers.

in reply to fbirder


Many thanks for your clear reply

I have to say that I have seen improvements all round, not all neurological stuff eliminated as yet but considering that I havent had much b12 over the past 7 weeks I guess my nervous system must be reacting to the very high levels of Sept and Oct, also mcv dropped a little to 100 ( have been supplementing folic acid, I understand that this could push mcv down ?? ) one more concern it that my haemoglobin level is now over the high end range.

Also I have noticed more frequent visits to the loo, can high levels of b12 cause this, its nothing like prostate problem symptoms, these are proper visits, sorry for the graphic explanation.

You may also like...