Hi all, I've been diagnosed as 'not absorbing B12' but am not sure why. I didn't test positive for IF antibodies (although I understand that's not accurate) but think my stomach acid is probably low. Anyway, that's not my question for now. I'm self-injecting B12, was weekly and now once every 3 weeks seems to be OK. The peripheral neuropathy I was experiencing is much better. It's taking longer with the low energy but I think I am seeing slow improvements. I've been trying to read and understand the whole B12 absorption thing. This is where I'm confused: B12 injections bypass the need to absorb it and go straight into the bloodstream to be stored in the liver. I understand that the liver is able to store large quantities of B12 over many months. So how come we need to inject so often? (I see there are very variable frequencies for different people's needs and I know there is no way I can wait the 3 months the GP is offering). Is the stored B12 not bio-available? And if not why not? Are there any resources I can read around this?
PS It's been so helpful being part of this group- so far I've just been reading and not commenting but it's been really helpful and has stopped me feeling so isolated in this. So thank you all.
Written by
JanMoon
To view profiles and participate in discussions please or .
Search on enterohepatic circulation of B12. You're correct that your body is storing B12 in the liver, most likely perfectly normal and in a person without PA the body would normally recycle this B12. There is maybe 2 to 3 years of B12 stored here. However, the body recycles this B12 from the liver through your common bile duct into the duodenum (first part of small intestine). It is normally a small trickle amount rather than on-demand. Once in the duodenum the B12 follows the normal absorption process through the digestive system. In other words it must bind with Intrinsic Factor which allows it to be absorbed in the Terminal Ileum (the last part of small intestine). For those with PA and lacking IF this recycling is broken and the B12 from the liver as well as that from recently ingested food just passes through unabsorbed.
For those with PA the only stores we have available is that currently in our blood serum. A very short lived storage hence frequent injections. I note that injection frequencies vary amongst individuals as we are all different. Also depends on what stage of disease we are each in. Some inject EOD, some weekly, some monthly, just listen closely to your body, Shhhhh! You'll learn to notice little barely perceptible things, maybe a pain in that right toe, a momentary fleeting stabbing pain in your foot, a little wobble in your walk, or a headache, fatigue, brain fog. All of these may be signs that your cells are yelling at you like a newborn wanting to be fed! 🙂. The trick is to time these incidents and inject a few days before they happen. I personally have settled on every 6 to 7 days. But sounds like you're listening to yourself though.
That's a great question. Firstly, liver stores of B12 being unavailable does not apply to all those with "B12 deficiency" but rather only those with the autoimmune condition Pernicious Anemia where we cannot absorb B12.
To answer your question, the half-life of injected B12 in human serum has been measured to be ~6 days. Meaning that half of what you inject is excreted or used by the body in that time. Another way to look at it is if one injects 2000 mcg of B12 then 6:days later there will be 1000 mcg remaining. And so in after 6 more days or day 12 there will be 500 mcg remaining. This continues for 5 or 6 half-life or 30 days. I'm not sure but this is quite possibly why doctors in US typically prescribe once monthly B12 injections for those with PA. Note that although essential and critical to life, the human body needs only a miniscule amount of B12, about 72 mcg per month to function properly. Also the half-life of B12 varies a bit from individual to individual and is influenced by sex, age, health, BMI, etc.
I've found no studies or data that supports 3 month injection interval is OK for those with PA.
I happen to inject 2000 mcg of methylcobalamin about every 6 to 7 days only based on how I am feeling.
Thank you. I'm so scared. I'm having horrible neurological symptoms and neuropathy and worried I'm going to die like this. Starting to even question if b12 is my issue
I noticed you joined in October of this year. If that's about when you were diagnosed and started supplementing B12 through injection AND you're still having neurological and peripheral neuropathy then your current frequency of three weeks may not be enough. If it were me, just a suggestion of course as I'm not a doctor, I'd try at least weekly again or even EOD. There is a short window to heal nerve damage before it may become permanent. It also can take a year or more to heal these nerves after start of B12 therapy.
In fact, through my experience, continued nerve damage does not just stop when you start injecting. It really depends on how severely deficient you were when diagnosed. Nerves become exposed and damaged when myelin sheath becomes eroded. This is the protective sheath that covers the nerves of which B12 is required to maintain. As this sheath is being healed and repaired with this elixir of life the nerves remain exposed and damaged can continue to occur while this healing is taking place.
As Enuffisenuf said "it takes time."
Keep your injections frequent until improvement stops... Maybe a year, maybe longer. Also know your dose.
YES, it is scary. Trust me no one on this forum wasn't scared of "what the heck is happening to me!" At the start of treatment. Scared is OK. Just try and stick with it and take little victories as they slowly happen.
Like "This can't possibly be it, I'm still getting worse. Everyone else started getting better, so maybe there's something else. Something they've missed or not tested for and identified yet."
Luckily, I was later sent to an ENT specialist, who told me that I quite clearly had a B12 deficiency. That I was doing the right thing by self injecting frequently, and that I would have to be patient and not give up, as it would take a very long time, but that I would improve.
Shordae - keep going. JanMoon - you are right : the people here are really supportive and can keep you on track through this experience. Rexz - Thanks !
Hello,As others have said it takes time. It may be hard but you have to try not to stress. Your body is undergoing alot. I know how you feel. I felt like it was my last as well 😌
I try to stay positive and not tell alot of people bc it takes up energy having to explain to everyone and then slightly irritating bc they may perceive it as something that's not dire.
Advocate for yourself! Take care of you! Have some self care routines, delete negativity as much as possible. Like others I increase my dose based on how I feel. I couldn't survive on weekly more is needed for me. Know your body and keep fighting!!
I'm newly certified having autoimmune gastritis, blood test was positive and the scope confirmed the damage and yes PA did rear its ugly head which is how I got diagnosed. You seem really well versed with all of this confusing PA mess of contradictory advice and findings, so would be interested on you opinions.
I am now at the test dummy phase of injections (every 3 months) which I do not believe will be sufficient.
I started taking sublingual 1,200mcg Mecobalamin midway through my last monthly shot because I felt my energy waning I stopped them a week before my last bloods performed the day before my last monthly shot to try to not skew the results. the results were that I had borderline B12 sufficiency at 280 (sufficiency > 300) and my active b12 at 62 (sufficiency > 40).
I will go down the self injection route if it required. At the moment I'm just testing the waters.
To throw a spanner in the works of understanding my low energy my ferritin levels dropped from 182 to 40 in 2 months (pre/post B12 injections, should be 30-400, I suspect the levels were not correct to start with, perhaps PA showed a false high level). I'm now on iron supplements with added folate and taking vitamin c to aid absorption. The part of my gut that absorbs iron is good so should be no issues there.
To add to the confusion of my low iron levels, I previously worked in IT for over 25 years and am now working my ass off as a domestic cleaner which is fast paced and I'm sweating my ass off anywhere between 2 -5 hours each day. Not a lifelong career, but good enough to get back into the world.
I am totally shocking my system in every way so it is hard to figure out what is happening and why! On a bad day over the last few years a slow 10 minute walk would push me, so I am clearly much better, but never want to go back to my previous zombie functional state.
So, after this long spiel, a few questions.
Why would daily sublingual B12 not work? If only 1% was absorbed into my blood from the mucus membrane it would make 12mcg per day which should suffice.
Is active B12 a good measure of absorption of B12 and if so, what should it be for someone with PA. My only measures are from my last bloods at 62 (should be > 40), previously they were undetectable and have not and will not be automatically measured unless my regular B12 results fall below sufficient (> 300) so have no reference how they have changed over time?
Is there an optimal ferritin level for someone with PA?
Is there an optimal folate level for someone with PA?
Autoimmune gastritis being an autoimmune condition, does that mean that it at times it could go into remission and your gut could heal somewhat? (new to this stuff, aiming high for my wishes, don't want to get any symptoms down the track)
Lastly, am I bat shit crazy?
Be honest, especially with the last question. This disease is frustrating in that general doctors have no idea and it is difficult to know if you are finding the right information and making the correct decisions for yourself.
I would appreciate any insights that you may have and will forward many positive vibes and karma to you in appreciation.
There's a lot to unpack here so I've got to digest..maybe not the best word considering the topic, how about absorb, nope not good either OK just read through again! 😜 So will answer all your questions in a bit. But all very good questions and your curiosity and ability to ask those puts you a bit ahead of the game.
Let me start for now by answering your last question first... Emphatically YES, you are bat shit crazy! As evidenced by joining the bat shit crazy club here with the rest of us. 😂
I'll eread and respond more whilst I have my morning coffee ☕
Lovely to be amongst kindred folk. Thankyou or your diagnosis, although I suspect I have had this mentioned before. Oh, I forgot to order my cute bat earrings, true.
I will look at your answers tomorrow, don't rush yourself, I need to get rest its almost 1am. Work at 10am, need rest.
Having P.A.means that your stored B12 is unavailable to you, because you have no Intrinsic Factor .
You will need to inject B12 often enough to keep B12 symptoms at bay . Glad to hear that you have found a routine that is helping you.
we do not know why patients require differing regularity of injections. I know people who find 3 monthly fine , and I know someone who has to inject twice a day .., and others anywhere in between .
A great deal of research needs to be done for this “Cinderella “ condition
Most of the medical profession are not well informed about it . We have to find our own salvation I’m afraid .
For neuropathy I took 15 mg of L-Glutamine powder from Klaire Labs 2x a day and my neuopathy disappeared. I haven't taken it in few years and the neuropathy has not returned. Ask your doctor before trying anything like this. Just thought it might help .
With PA, we lack intrinsic factor. You can think of that as the delivery truck that picks up the B12 in the digestive track and delivers it into the body. Our trucks are no longer working. The mechanism for recycling B12 goes through the liver. But it requires the truck (intrinsic factor) to get it back into circulation again. So for people with PA, the recycling is not working either. The IF anti-body test has a very high false negative rate. If it is positive, you have PA. But lots of people with PA get a negative on that test, but it does not mean you do not have PA. You say your peripheral neuropathy is better. That is a strong sign you have PA. I would encourage you to keep up every other day injections until it is gone. Then choose an interval where you do not get symptoms back. I get tingly toes in 3 weeks so I inject once per week. Very best wishes!
Injections are active and stay in the blood, I believe. B12 stored in the liver is inactive; you need adequate IF to convert it, I think.
The NHS test could show say a total B12 value of 200 (can't remember the actual units!) so active B12, which is what you need, could be as low as 20 (10% of 200) or as high as 60
Danger level is lower than 30 to 40, I think. So an NHS test lower than 400 could mean imminent danger.
Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.
Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.
Confused about B12, iron and haemoglobin
B12 testing: I need some answers! 
B12 deficiency with dizziness
confused about B12 levels
B12 and folate relationship.
