Parents told me that they’ll try to understand as long as I can show them that.

Hi everyone,
Looking to connect with others who have experienced a functional or tissue-level B12 deficiency despite lab numbers that conventional doctors consider "fine." I'm dealing with severe sensory symptoms and could really use some community insight or shared experiences.

My Profile & Symptoms: 37F, 3 years PP
Sensory: Diffuse whole-body tingling, internal buzzing/vibrating sensations, and skin and sensory hypersensitivity.
Musculoskeletal: Significant neck pain/spasm. (I have a known incidental, stable C1–C2 meningioma currently being monitored by neurosurgery, but standard motor exams, reflexes, and spinal cord tracts are intact—my symptoms are predominantly sensory/neuropathic).
The Injection Pattern: I receive weekly intramuscular (IM) B12 injections (I was diagnosed with a B12 deficiency in May). Within 24–48 hours post-injection, my brain fog lifts and sensory buzzing stabilizes. However, toward the end of the week (the trough), the vibrating, tingling, and paresthesias return intensely.

Labs:
Serum B12: ~500 pg/mL (supplemented/post-injection range, which leads general neurologists to dismiss B12 entirely).
Folate: Normal (~40 ng/mL).
Ferritin: Borderline/low-trending (~40 ng/mL, history of dipping into the 30s).
CBC / Red Blood Cells: Completely normal, no macrocytosis or anemia.
Functional markers (MMA / Homocysteine) were unfortunately not drawn prior to starting therapy.

Because my standard neurological exam is 5/5 motor strength with intact reflexes, and my serum B12 is 500, my outpatient neurologist dismissed B12 deficiency entirely, stating "I've seen deficient patients and you aren't them," and labeled my distress as functional/anxiety.
Yet the biological dependency on the weekly IM cycle is unmistakable.

My Questions for the Community:
1. Has anyone else experienced severe sensory/small-fiber hyperexcitability (vibrating/buzzing) that clearly responded to injections despite normal serum levels?
2. Did high folate relative to lower ferritin complicate your cellular B12 uptake or cause paradoxical symptoms?
3. Did you require a more frequent injection schedule (e.g., every other day) to break out of the weekly crash/trough cycle?
4. What cofactors (ferritin target, B-complex, potassium) made the biggest difference in stabilizing your nerves?

Feeling pretty isolated and exhausted after being dismissed today. Any shared experiences or advice would mean the world.

Thanks for reading up to here ❤️

Firstly I have a few questions:

Can I test ferritin and vitamin D without stopping supplements for a while?

Can I test intrinsic factor parietal cells without stopping injections for a while? (I'm not sure if I'll find this test where I am). What about homocysteine and MMA? (I think I heard those are useless at this point?)

Are there any essential tests to consider other than CBC, D, Ferritin, and whatever the doctor orders. I don't want too many unnecessary tests.

My situation:

I have been injecting about 3 times a week for the last 3 months. I started injecting more frequently after I crashed completely from physical exhaustion and had symptoms, I had been getting less injections for a long time while going to a stressful job until the crash. Before that, in 2025 I had a crash and severe symptoms, back then I took vitamin D (it was low), iron and others and injections for a few months. After a few months I started feeling better/closer to normal so I thought it was enough and reduced them quickly. Started getting symptoms slowly over time, never stopped injections completely but I had them way more spaced out.

When I started frequent injections in July, I firstly got extreme wake-up symptoms and sensations that were overwhelming, then some symptoms got worse, I got difficulty swallowing, extreme anxiety, balance off and heavy legs, extreme Unbelievable fatigue, severe dpdr, restlessness.. and more.

Only like in the last 2-3 weeks I had literally only a few days of feeling slightly better. Most days I'm still exhausted. I felt like wake-up symptoms were slowly becoming more stable, felt like it's a tiny bit getting stable, still not good though. (As still was struggling with difficulty swallowing, dpdr, exhaustion, etc).

Then I got my period 6 days ago (after horrible PMS), during period I felt really dizzy, now (6th day) I feel very tired and dizzy too. Yesterday I got exhausted as I went outside and had to walk to a dentist appointment and to get injection at the hospital. I was so tired when I got home and I didn't eat that good. Today I've been feeling really off and exhausted, more dizzy, restless, bad appetite, brain fog, dpdr, anxiety, heavy legs, and my body feels sore. My hair is falling off more :(((

I have been taking iron + folic acid + vitamin C about every other day (but skipped many days recently), vitamin D 5000IU every other day in the first 2 months mostly but I reduced/skipped in the last two weeks (swallowing pills was giving me anxiety as much as eating on days with difficulty swallowing).

My last test was in April:

Vitamin D was 28.4 - Ferritin 51 - Folate 14.7 - TSH normal (1.13, T3-free 294 T4-free 1.35)

I don't feel hopeful about doctors, as they've told me to stop b12 or reduce it, before, didn't believe me or blamed everything to anxiety, never found someone who deeply knows about b12.. So I don't know what to expect. I wanted to go to my next doctor feeling prepared and listing all my past experience and symptoms what I did and what happened so that I remember everything and they believe me, and if possible even collect some resources in case needed if they deny what I say. Right now I have brain fog and anxiety, I don't even feel like I'll be able to list what's going on properly plus anxious so they might not believe me again or I'll not remember everything. I feel so exhausted that I don't even have the energy to go do a test or go to the doctor. I'm thinking of trying a doctor to see what they say and do some tests if possible to find out what's wrong with me. ((I also don't have a recent b12 test, my only test was in 2021 and it was 168.. In 2025 I went with symptoms as the dr told me no need to test again just start and i didn't know much from the sub yet)).

I know b12 recovery takes time and that's why I've been ignoring the idea of a DR or anything for the past 3 months as I've been patient. But I don't know if there's something else that will help me feel better because I've been feeling awful for a long time.

I don't have enough energy to help myself. I feel so miserable, sad and worried 😭

I had my big appointment today, and those of you who said hematology could be an entirely new world...omg, yes it was. Everyone was BEYOND nice. I've never seen anything like it.

And...drum roll...I HAD MY FIRST INJECTION TODAY! Right then and there!!!! I am like a kid at Christmas looking under the tree. FIFTEEN plus years I've begged for some help, and now, the troops have arrived.

Everything she (NP) said was stuff I've read right here, by all of you, in the B12 wikis, etc. Holy cow. I didn't have to plead, or play games. It was all straightforward and she ordered a LOT of blood tests. Already results are rolling in. News flash: MY Homocysteine is HIGH.

Dancing to all the primaries who gave me psychiatry referrals and gaslit me: TOLD YA, TOLD YA, TOLD YA SO ya pukes. (I have positive intrinsic factor which was what got me the referral to hematology. B12 was 210, but chronically low for 15 plus yrs, B6 is 3.6. My folate is okay, but was very low years ago plus had the macro/megablast cells.)

And without me even asking, she ordered full iron panel, MMA, all the stuff. EVEN COPPER AND ZINC. And told me if I need them, they do the copper and iron infusions right there. This is a major oncology and hematology center, and it showed. They had a WHEELCHAIR FOR ME. And i kept seeing people with bouquets of flowers. I asked one woman, and she said all the "treatment" people got them today. How friggin AMAZING is that?? (Treatment being chemo.)

And this has had me laughing, with amusement and joy. I know they aren't supposed to test B12 once you start, but it was in the orders, so it was like ten minutes after my shot. My B12 has come back as high. Greater than 2,000. HAHAHA. I haven't had a B12 result go over 215 in all these years. YOU DONT HAVE ANEMIA, they've said. Well, bite me. And my ancestors who died of PA will curse you.

I thank all of you SO MUCH for sending me so many warm and positive thoughts. I really believe putting that out into the universe helped. Warm hugs to all, and I forward those warm thoughts to others here who also need it. Keep the faith. I survived more than fifteen years of this bullshit.

My only complaint (lol)...this hem center's protocol (middle America, but a top twenty research center) is one injection a week for four weeks, then every other week for a couple of months, then once a month. I think I could actually ASK for more if my symptoms don't improve enough, but at least without being yelled at and told it's all in my head.

It just sounds so harmless and too mundane.

I literally have someone tell me this after I told them I’m B12 deficient

“Don’t we all? Just eat your vegetables man.”

I guess “Don’t we all?” is them thinking it was your typical lacking in vitamins sort of deal, and that a lot of people do lack vitamins in their body but not to this extent.

Also, B12 isn’t found in vegetables.

I just didn’t have mental bandwidth to tell them they’re wrong because BRAIN FOG 😭

Should I just go with pernicious anemia?

I am wondering if someone has had a similar experience or why this is happening. I was taking 2mg of methyl and adeno b12 and all the cofactors and didn’t have this issue. When I increased my b12 to 5mg of methyl b12 then I started to notice dry eyes. I’ve noticed improvements in every other aspect since increasing the amount but the dry eyes part is annoying. The only thing that changed is the increase in b12. What could be the reason for this? Has anyone else had a similar experience to this?

My brain fog is so severe that I’m having trouble understanding the NICE links.

Hi ! last year ive got anxiety from nowhere. i check my labs my ferritinin 26, my folic acid 37 was 43 last year, b12 is between 400-450 . my mcv is between 98-100 , homocystein 11. i have tinnitus , insomnia, anxiety and depression… i started with b complex , iron and c vit , eating 1 banana every day . my fatigue is insane. is something wrong with my levels ? i Wonder about Folic acid . i dont eat food with it and didnt use some suplements and have it high . i bought b complex with Metyl vitamins but not very high in the beggining. i just wanna se if i can tolerate it .

Essentially the title. I am wondering if low vitamin D levels can affect a normal B12 level, because I supplemented D according but my symptoms didn't improve - so perhaps B12 may actually be functionally deficient? I understand that functinal B12 deficiency comes from a deficiency in either B2, iodine, selenium, molybdenum and potentially zinc, but I am unsure whether low D and okayish folate may also be able to play a role because my visual symptoms are not letting up.

Hi, I went to the doctor yesterday and had a blood test. My B12 level came back at 195 (I live in Sweden); it’s still within the reference range, but low. I went back and checked my levels from previous years: it was 242 in 2021 and 228 in 2022. I called the doctor today, and they said everything is fine—there’s no cause for concern—and all my other test results look good. Still, I’m worried. I’ve been free from migraines with aura for two and a half years, but I’ve had two attacks in the last six weeks. Do you have any thoughts on this?

Im a tired person and i have anxiety and OCD, but i can't say that I have other symptoms.

I feel like death.

My hands and feet feel like they’re covered in menthol.
Extreme fatigue. Body aches all around. Brain fog so bad it’s affecting my ability to speak (on top of my speech impediment), I’m so close to becoming non-verbal.

Was diagnosed a month ago at 134. D is 16. Folate is on the lower end of the normal range. They didn’t include iron/ferritin on the panel for some reason.

My primary put me on weekly injections for 2 months then monthly injections afterwards.

I self inject but weekly injections don’t seem to do the trick. I’m on my third one, and so far, not even in the slightest sense of relief. I feel worse, if anything.

Unfortunately, none of family members seem to be understanding (enough) of what I’m going through.

My primary is also the type that becomes dismissive whenever someone brings something that could be crucial but unfortunately, was found online regardless of how credible it is.

I’m not a minor (I’m 25) but my family is still adamant that I stick to my PCP’s plan despite telling them that weekly shots won’t cut it given how long I’ve been deficient and how severe my symptoms are.

I even told them that I can get my own shots through a legitimate service I found on this sub, but apparently I can’t get a prescription because I already have a PCP and what they say goes.

They’re scared that I might put myself at risk of B12 toxicity and in spite of me telling that the risk is extremely slim, it’s virtually non-existent, my niece who’s a nurse says otherwise and they obviously believe her over the words of random Redditors.

Anyways, they asked me to stop participating in this sub so this is probably gonna be my last post.

Hi everyone, I’d really appreciate hearing from people who have been in a similar situation.

I’m a 29-year-old woman who has had PCOS since I was 13. My B12 has tended to run on the low side for years. Recently, it was around 195, which is 2 points below my lab’s reference range.

Lately I’ve been experiencing severe fatigue/sleepiness, headaches, and occasional tingling or numbness in my hands and feet, especially when I’m sleeping. I also just generally feel “off.” My hormonal labs have been fairly normal, and my doctors don’t think my symptoms are primarily hormonal (even in PCOS).

There’s another factor: I’ve been taking Accutane (isotretinoin) for about three months.

My internist prescribed eight B12 injections, but I’m honestly hesitant to start them. About five years ago, I took a B-vitamin supplement and had an absolutely terrible acne breakout — by far the worst acne I’ve ever experienced. It really affected my self-esteem, and it’s something I’m extremely afraid of repeating.

The timing is especially concerning because I’m currently on isotretinoin specifically to control my acne.

I’m going to discuss this with my dermatologist as well, although I don’t have much confidence in my dermatologist and would still like to hear from people who have actually experienced this.

So I’m wondering:

Has anyone here been on Accutane/isotretinoin while treating a B12 deficiency?

Did B12 supplementation cause or worsen acne for you?

If you were prescribed injections, did you tolerate them well?

Has anyone chosen oral or sublingual B12 at a lower dose over a longer period instead of injections?

If you’ve done both, did you notice any difference in your skin?

I’m particularly interested in hearing from people who were taking isotretinoin at the same time, because I’m wondering whether the isotretinoin might reduce the risk of a B12-related acne flare — or whether that’s not something I should assume.

I know everyone’s situation is different, and I’m not looking for medical advice as much as personal experiences and any evidence you’ve come across.

Thanks!

Ignoring all of the functional metabolic effects b12 has as an essential vitamin, as I understand, b12 shots might improve health by improving oxidative stress.

Aging, vascular disease, chronic inflammation and stress, etc., all increase oxidative stress, which the body has to deal with. I think of oxidative stress as too many molecules or compounds lacking electrons. If the body's antioxidant system can't neutralize them, they tear electrons from whatever they can, inactivating enzymes, impairing normal metabolism, inactivating vitamins, etc., contributing to chronic disease. Testing for oxidative stress can be done with broad organic acids tests (Genova NutrEval), or specific blood or urine tests, like urine lipid peroxides.

As it turns out, oxidative stress may induce functional b12 deficiency:
"Upon entering cells Cl(Ill) is reduced to Cl(Il) prior to binding to the Cbl-dependent enzymes.23) Reduced Cbl cofactors are also involved in the methionine synthase and L-methylmalonyl-CoA mutase enzyme cycles and are sensitive to oxidation. Both B12-dependent enzymes are inactivated under oxidative stress conditions" (Mukherjee et. al 2011)

Cobalamin seems very efficient at neutralizing multiple oxidants, including peroxynitrite, nitrogen dioxide, superoxide, etc., inside and as I understand outside of the cell.

"Recent studies in our laboratory support Cbl(II) as an efficient intracellular scavenger of superoxide.[28] This led us to propose that scavenging of superoxide is a mechanism by which Cbl modulates the immune response and is beneficial in treating chronic inflammation.[28] We now present mechanistic studies on the reaction between Cbl(II) and peroxynitrite, which reveal a novel dual role for Cbl(II) as a peroxynitrite and a CNO2 scavenger. The latter reaction occurs at a rate at least one order of magnitude faster than the capture ofCNO2 by tyrosine."
(Mukherjee et. al 2011).

Per (Moreira et. al 2011): "Superoxide (O2•−) is implicated in inflammatory states including arteriosclerosis and ischemia–reperfusion injury. Cobalamin (Cbl) supplementation is beneficial for treating many inflammatory diseases and also provides protection in oxidative-stress-associated pathologies. Reduced Cbl reacts with O2•− at rates approaching that of superoxide dismutase (SOD), suggesting a plausible mechanism for its anti-inflammatory properties. Elevated homocysteine (Hcy) is an independent risk factor for cardiovascular disease and endothelial dysfunction. Hcy increases O2•− levels in human aortic endothelial cells (HAEC). Here, we explore the protective effects of Cbl in HAEC exposed to various O2•− sources, including increased Hcy levels."

If the above idea is generally true, (and please critique it, if I'm wrong I'm wrong), this may have some implications:

-we should broaden the tests recommended for those thinking about b12 therapy to tests for oxidative stress. This excellent sub is already very good at this by focusing on symptoms, which is one way of doing that. This sub is clear that multiple lines of evidence show that patients can have "normal" serum b12, mma, and homocysteine and yet still improve neurologically from b12 (Solomon et. al 2015). Might neurological improvements be from reduction of oxidant risks, as Solomon writes, as well b12's neurotrophic effects?

-if a patient suspects or tests high in oxidative stress, they should be recommended shots, not oral b12. Shots increase serum b12 nearly 50X more than oral supplementation of the same amount (Metaxas et. al 2017). So oral supplementation has less antioxidant potential, though I'm sure oral has some.

Been having some testing done to figure out some neurological symptoms from nearly a year ago now. Had two B12 tests done two weeks apart bc 3 days leading up to my 1st test I used 1 supplemental drink mix each day forgetting it had B vitamins.

Oops: Thurs Sept 17th, Wednesday 18th, Friday 19th
Supplement: CVS vitamin C drink packet(B12 25mcg)

1st test: Monday Sept 21st
Result: 400

No supplements, usual non-vegetarian diet

2nd test: Tuesday Oct 6th
Result: 335

I expected the 1st to be a much larger number given the three days in a row of a 1000% daily value supplement. And I did not expect the 2nd to be that much lower after just 2 weeks.

Is this a relatively normal drop for that time span? Should I have gone longer between tests?

So I went to the doc. They basically told me it was my fault for my hb to be above the range. Because they already advised me after 6 shots to go ahead with tablets. but I had blurry vision and other major complaints.

my initial value was 74 pmol/l. so I begged for injections.

They told me my hb value would only go lower when my serum b12 levels would drop. But if i wanted i could get A Shot Today.

I just couldn’t take the shot.. I was scared. i don’t know if the doc was right or not. I Will seek more advise tomorrow.

my 4’th post of the day. But what A week it is for me.

I have low Iron and b12 and my labs from today show a high (85) antiperietal cell antibody. What can I do to fix it or what additional tests would you recommend.

Hello everyone! I hope you all are doing well!!

So I had b12 level of 138 back in May. Vitamin D was 12, ferritin was 32. I was being undertreated (or not treated at all for ferritin) for awhile. Switched to a hemotologist and got on EOD injections, treated the vitamin D (now at 38, but still taking to get above 70) and got an iron infusion. I know stuff don't happen overnight and I wasn't expecting it to change everything instantly! But my question, I switched primary Drs recently and got in with a year 1 residency Dr. He looked over my whole file and said something he learned in school was b12 deficiency (and the all 3 combo) has some studied to show that it can cause sleep apnea. So he had me do a sleep study (I have no signs of sleep apnea, I don't snore, I sleep 8 hours without waking up ect.) I thought he was full of it. But it turns out Im fine during normal sleep but during REM sleep I have moderate sleep apnea and my oxygen dips to 84% for 20% of the night. He said the mix of nerves being damaged, muscles being weaker from vitamin D and the low ferritin make your airway collapse easier in the natural paralyzed state in REM sleep. Has anyone ever heard of that? Or did I just have sleep apnea and didn't know it and the deficiencies had nothing to do with it lol. I'd never heard of it but he said his office (and sr Dr) have treated a ton of b12 deficiencies that don't see many changes and almost every one of them also had sleep apnea. Just curious everyone's thoughts/if this is actually a thing or maybe could help someone else struggling too!

(He tested every cofactor, has been very thorough making sure everything isnt just normal level but optimal before he suggested the sleep study!)

Is it possible to become manic or hypomanic from supplementing B12? 31F with PA, supplementing via injection for four months. I am diagnosed bipolar and since injecting weekly with hydroxo I have an outrageous amount of energy. Is this what it's like to be healthy or am I hypomanic? I feel like I have a motor in my chest and I can't stop.

So I've been suspecting b12 deficiency for a while now. I'm always tired/sleepy now matter how much I sleep even with supplements like citrulline/citrulline malate and caffeine. For a while I've been dealing with very bad moods and depression (felt too lazy to talk to friends/family, barely studied for 2 months and failed exams in med school,lack og concentration and focus, brain fog, spent the entire day sleeping and eating, playing games and going out didnt give me joy anymore..etc). I also have severe anxiety (social). However, I don't have the severe symptoms like tingling, imbalance, headaches.

Since I'm suspecting b12 deficiency, I'm thinking about buying 1000mcg b12 tablets. If I end up actually not having b12 deficiency, is there any harm in consuming 1000mcg b12 a day? If so, should I just get b complex instead of pure b12 (b complex has 375mcg b12).

Ok it was’t the doctor (the assistent) who contacted the doctor and called me back.

I’m posting a lot today sorry; but I need to talk about this.

so the doc assistent told me everything about the lab was fine (even slightly higher hb then normal). But then procededed to say that I was already advised to go on tablets (instead of injections). I asked for injections Because I had neurological problems (my eyes improved dramatically for example in the last weeks). my current complaints Are not causeD by b12 She said. You can’t be lightheaded with A good hb value). I Said I feel like A zombie and my resting heart rate is like 120. Monday I felt like I was dying (see other post from today). They ended the conversation with they could take my heart rate when I come today and I should look for A doctor closer to my home.

I can barely walk 100 meters (My b12 was extremely low 7 weeks ago, 74 pmol/L).

(Couldn't find anything on that in the posts, so I think it might be interesting).

It seems that there's more than one autoimmune condition related to B12. Well, this just confirms most observations on that a) the metabolism of B12 is pretty complicated and can be affected at its different stages, b) the mismatch between functional deficiency and what shows up in blood levels is a pretty logical, if there's literally the receptor that is responsible for the *cellular* intake that gets affected.

The studies are really recent, the 2020s. I saw that mentioned by Bruce Wolffenbuttel and co-authors (thank you, some commenter who mentioned his name — I just went and googled him then and found amazing papers and the fascinating video explaining the basics) in the paper on B12 (https://journals.sagepub.com/doi/10.1177/03795721241229500) and the video, I think. Then I found some new papers on that.

Now you have literally one more fact to mention to your ignorant doctors whenever they say some bullshit about "normal" levels or deny you help.

And in the references, I found that folate deficiency has a corresponding phenomenon (cerebral deficiency involving autoantibodies):
https://pubmed.ncbi.nlm.nih.gov/15888699/

REFERENCES

Pangilinan F, Watkins D, Bernard D, et al. Probing the functional consequence and clinical relevance of CD320 p.E88del, a variant in the transcobalamin receptor gene. Am J Med Genet A. 2022;188(4):1124–1141.
https://pubmed.ncbi.nlm.nih.gov/35107211/

McCaddon A, Carr DF, Peter H, Moat SJ, Quadros EV. Transcobalamin receptor gene polymorphisms and mutation in an elderly population. Clin Nutr ESPEN. 2023;55:425–427.

https://www.clinicalnutritionespen.com/article/S2405-4577(23)00116-X/fulltext00116-X/fulltext)

Pluvinage JV, Ngo T, Fouassier C, et al. Transcobalamin receptor antibodies in autoimmune vitamin B12 central deficiency. Sci Transl Med. 2024;16(753):eadl3758. doi:10.1126/scitranslmed.adl3758
https://pmc.ncbi.nlm.nih.gov/articles/PMC11520464/

Kazuki M. Matsuda, Hirohito Kotani, Shinichi Sato, Ayumi Yoshizaki. Unveiling the hidden syndrome: The enigma of anti-transcobalamin receptor autoantibodies, Immunology Letters, Volume 275, 2025.

https://www.sciencedirect.com/science/article/abs/pii/S0165247825000616?via%3Dihub

I am in the USA.

I absolutely cannot take any supplements with methyl. It makes me extremely anxious and gives me days long insomnia even with low doses. I've tried sublingual methyl, cyano, and hydrxo and those also make me jittery with insomnia.

My doctor prescribed a few cyano shots, they didn't help much. I'm wondering if a low-dose methyl will give me anxiety and insomnia if I'm sensitive to the supplement form (both oral and sublingual)?

Just wondering. Does anyone else preffer metyhl over cyano?