B12 injection dosage: I'm a 60 year old... - Pernicious Anaemi...

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B12 injection dosage

I'm a 60 year old man living in the US. Despite always exercising & eating a very good junk-free diet, I have basically felt like **** every day of my life since I was about 20. No doctor has ever been able to do much to help me. I've recently had some testing which has indicated low levels of red blood cells and hemoglobin, as well as low B12. Tried oral B12, which made no difference, I suspect I lack intrinsic factor, and have pernicious anemia. I'm trying to determine what a typical initial B12 injection regimen would be; dosage, frequency, number of injections, and also what the usual maintenance injection dosage/frequency typically is. Can't seem to find this online. If anyone here could give me some data on these issues, particularly with references to medical literature, I would greatly appreciate it. I have a doc appointment next Monday, and given the rarity of this condition, I don't expect my GP to know much about it right off the bat. Any other thoughts any members might have on this would be appreciated!

Thanks in advance,


33 Replies

Hi David it's not that it's such a rare condition it's just not recognised enough it seems in the medical field. You will get lots of good help on here it's an amazing forum.

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Here in the U.K. after being diagnosed with Pernicious Anaemia , one gets 6 loading injections over 2 weeks , and thereafter one injection every 2 or 3 months . I must point out it is often difficult to get a diagnosis because the test is notoriously inaccurate if it comes up negative. Each injection is of 1mg of B12 . Here in the U.K. the Hydroxocobalamin form is used . In the USA Cynocobalamin is the usual form . It is great to know that one cannot overdose on VItamin B12 . This dosage is not sufficient for many PA patients and they have to self inject because their doctors will not allow them

more . We are then forced to obtain supplies from abroad ( usually German online pharmacies , as injectable B12 can only be obtained here with prescription. . PA patients need different dosages to keep their symptoms at bay . I need an injection weekly ., but we are all different in our requirements .

Self injecting is cheap . But having them privately is expensive . One also needs to make sure of a good supply of Vitamin B9 ( folate in fruit and vegetables, folic acid in a tablet ) This vitamin works together with B12 .

Try to get injections through your G. P.

If you have P.A. it is an incurable autoimmune condition . You will need injections for life . That said , you can lead a healthy , normal life with the correct treatment . Unfortunately it really is a Cinderella condition , and many doctors are clueless about it . Find books on it on Amazon

“Could it be B12 “ by Sally Pachalok , is one by an American author . Our Chairman , Martyn Hooper has also written books on it ( Amazon ). You will get better replies than mine . Best wishes .



Some B12 websites that may be of interest

PAS (Pernicious Anaemia Society)

Based in Wales, UK. Has members in other countries.


PAS tel no +44 (0)1656 769717 answerphone

B12 Deficiency Info


B12 Awareness (US website)


Stichting B12 Tekort (Dutch website with English articles)


There are many possible causes of B12 deficiency eg diet, PA, Coeliac disease, H Pylori infection, Crohns disease, internal parasites such as fish tapeworm, exposure to nitrous oxide plus others.

Has your doctor excluded above possibilities?

Risk Factors for PA and B12 Deficiency




B12 books I found useful

"What You Need to Know About Pernicious Anaemia and B12 Deficiency" by Martyn Hooper

Martyn Hooper is the chair of PAS (Pernicious Anaemia Society).

"Living with Pernicious Anaemia and Vitamin B12 Deficiency" by Martyn Hooper

Has several case studies.

"Could it Be B12?: An Epidemic of Misdiagnoses" by Sally Pacholok and JJ. Stuart (US authors)

Very comprehensive with lots of case studies. There is also a paediatric version of this book "Could It Be B12? Paediatric Edition: What Every Parent Needs to Know".

The way B12 deficiency is treated varies from country to country. Even the type of B12 used in treatment can vary. In UK, NHS tends to use hydroxycobalamin and I think doctors in US often use cyanocobalamin. There is also methylcobalamin and adenosylcobalamin. The frequency of treatment may vary with type of B12 used.

I am not medically trained. More B12 info in pinned posts on this forum.


Thank you all for the terrific replies! Very helpful, lots of useful information. I have had many of the classic symptoms for years, in addition to the test results, peripheral neuropathy, abysmal memory, clumsiness, orthostatic hypotension, gut and pain issues. It really would be life changing to have these at least reduced. I've seen the injectable B12 online, I believe it's also prescription in the US, is the online stuff any good? Doing it at home would be much easier.

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It is recommended that you have your first injection done by a medical professional. Although it's extremely rare it is known for some people to have an anaphylactic reaction to an injection. If this should happen then you want it to happen somewhere with the people who know how to handle it and the equipment to do so.


Yes, your gut is also affected if you have P.A. Bloating, burping stomach pain etc. . The Intrinsic Factor Antibodies that cause the condition attack the parietal cells of the stomach . These cells produce both Intrinsic Factor and stomach acid , causing low or no stomach acid production . (Hypochlorhydria/Achlorhydria) Lack of stomach acid upsets the stomach flora .i found that a good water based Probiotic help this . Also acidic drinks help. Some people take Hydrochloric Acid with pepsin capsules .

I’ve never heard of anyone getting poor quality B12 ampoules . So inject with confidence when buying from a bone-fide supplier ( pharmacy )


Good morning SouthSounder from the U.K.

Anyone at any age, can become B12 deficient. However, certain people are at an elevated risk. They include the following:

Vegetarians, vegans and people eating macrobiotic diets.

People aged sixty and over

People who’ve undergone any gastric and/or intestinal surgery, including bariatric surgery for weight loss purposes (Gastric bypass).

People who regularly use proton-pump- inhibitors. H2 blockers, antacids, Metformin, and related diabetes drugs, or other medications, or infections such as h-pylori that can interfere with B12 absorption.

People who undergo surgeries or dental procedures involving nitrous oxide, or who use the drug recreationally.

People with a history of eating disorders (anorexia or bulimia).

People with a history of alcoholism.

People with a family history of pernicious anaemia.

People diagnosed with anaemia (including iron deficiency anaemia, sickle cell anaemia and thalassaemia).

People with Crohn’s disease, irritable bowel syndrome, gluten enteropathy (celiac disease), Pancreatic insufficiency, or any other disease that cause malabsorption of nutrients.

People with autoimmune disorders (especially thyroid disorders such as Hashimoto’s thyroiditis and Grave’s disease) Type 1 diabetes, vitiligo, lupus, Addison’s disease, ulcerative colitis, infertility, acquired agammaglobulinemia, or a family history of these disorders.

Can you see yourself among any of the above "people" - only as you say you have "a very good junk-free diet" that probably rules out the top one as long asit includes meat, fish, eggs, seafood and dairy produce which are the natural sources of B12,

Treatment for PA and non-dietary vitamin B12 deficiency is virtually the same.

The symptoms of PA are the symptoms of the B12 deficiency that it causes.

If the cause isn't dietary then it is an absorption problem so you need to find another way of replenishing B12 initially.

Most absorption problems aren't treatable but a few are - notably h pylori infection - which would mean that once that has been dealt with you would be able to absorb B12 from your diet so wouldn't need maintenance shots for life.

As you say you've "tried oral B12, which made no difference" it may well be that you have an absorption problem and will need injections.

Below are the "guidelines" used in the U.K. for treatment of P.A/B12 Deficiency - protocols in the U.S. will be different and you will need to discuss this with your doctor.

I don't know whether cyanocobamalin B12 is still dispensed or used for treatment in the U.S. but if it is you will probably need "loading doses" of 1mg every other day for two weeks or until there is no further improvement in your symptoms. That is not to say until all symptoms have "gone away" but until they no longer improve. Then you may need "maintenance" injections every four weeks.

If the injections prescribed are hydroxocobamalin B12 1mg the "loading dose" regime is still the same but the "maintenance" injection may be every two or three months.

Please note I am not a medically trained person but I've had Pernicious Anaemia (just one of many causes of B12 deficiency) for more than 47 years and still treated with cyanocobamalin 1mg injections now every three weeks.

I wish you well.


If you are close to the Canadian border you can buy injectable B12 (cyanocobalamin) over the counter there. Canadian companies tend not to allow mail order to the states for medicinal purposes but you may be able to get B12 being used for non-medicinal purposes. Some members of this forum go to slimming clinics for shots but it's quite expensive.

Your side of the pond tends not to have access to hydroxocobalamin which is the form generally used in the UK, so the forms used are cyanocobalamin and sometimes methylcobalamin. The only circumstances in which I wouldn't recommend cyanocobalamin is if there is a family history of lebers syndrome (quite a rare hyper-sensitivity to the cyano molecule. Some people react very badly to methyl - can cause high anxiety - and its much more expensive and much less stable than cyanocobalamin. It gets pushed as being a more natural form as it is an analogue of one of the forms used in the processes in your cell but reality is that the biochemistry of getting cobalamin from blood to cells makes this irrelevant.

In general cyanocobalamin isn't retained as long as hydroxocobalamin so maintenance dosing tends to be more frequent - think in the states they tend to do loading doses as daily for one or two weeks followed by weekly for a few months and then monthly. However, people vary a lot in what they need and the best thing to do is make a diary of your symptoms and follow those to determine the frequency with which you need injections.

This is a link to the American Familly Physicians page on treating people with B12 absorption problems.


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Hi Southsounder,

I'm here in the US, east coast, mid atlantic area. I was diagnosed with low B12 almost 2 years ago and while I had to diagnose myself, my GP was very helpful and seemingly knowledgeable after it was discovered. My treatment, which I think is the norm for the US, consisted of one shot a week for 6 weeks and maintenance shots (for the rest of my life) of one shot a month. When one shot a month didn't seem to be enough, I talked to my doctor and he suggested we try a shot every 3 weeks. Unless I am very active during a particular month, this seems to work for me. He was also very open to my questions about self injection. He had the nurse show me how to self inject in my thigh and gave me a prescription for 6 months worth of shots. I eventually decided to not self inject because I am a sissy so I go to my doctor's office every three weeks or so and get a shot. No appointment is needed. I just walk in between the hours of 9:00 am and 11:00 am and am usually out of there within 20 minutes. I still have lingering toe numbness which think is now permanent but other than that I feel so much better than I did three years ago.


I feel like I've been gipped of feeling better sooner. My loading doses have been every 2 weeks for 2 months (my final will be next weekend), then monthly. I feel barely more energetic, not at all what I was expecting. I'll be very interested in my lab results in a couple of weeks, and ask the doctor why such a different protocol from what others are getting.


What a terrific community here! So helpful. Interesting about B12 & Canada, I live in the Washington state capital (Olympia, also known as the "South (Puget) Sound" area) area, so definitely within driving range of British Columbia. I'm guessing my doctor will go along with trying this, all arrows seem to point in that direction in terms of causality, and there's no real downside even if it doesn't do the trick. I agree about the very small possibility of an anaphylactic reaction. My main reason for thinking of doing it myself is more convenience than anything else. I had a dog years ago with diabetes who I would give an insulin injection daily, so it wouldn't be the 1st time I've handled a syringe. I don't really know if any relatives had this, but so many seem to go undiagnosed, it certainly is a possibility. The only "diagnoses" I've ever gotten were "fibromyalgia" and "irritable bowel syndrome", which are frankly worthless and dismissive. Medicine has a very hard time telling a patient "we have no idea", never mind how frequently that is in fact the case. I'll take some time going over the data above, but again, THANK YOU to everyone who replied. BTW to MoKayD, where are you on the east coast? I grew up in Ohio, used to go to New York City frequently.

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Born and raised in Maryland. Halfway between DC and Baltimore. It's so funny, you're from Olympia, my husband and I are flying to Seattle week after next. We're doing a road trip from Seattle to Portland, Oregon. I'm really looking forward to this vacation. I've never been to the pacific northwest. I can't wait to see the hall of mosses and the grove of the patriarchs. Do you have any suggestions for good places to eat in Washington state?


I've been to Ballmer! ;-) DC, too. Yes, good places to eat in the PNW! I used to be a real foody until the gut part of whatever this is began. Might check out the Post Intelligencer for some restaurants in the Seattle area seattlepi.com/ If I were to recommend one single eatery in the Seattle area, it would probably be Herbfarm in Woodinville theherbfarm.com Excellent, though not cheap. Barking Frog over that way is also good willowslodge.com/barking_fr... Generally speaking, back in the day, I pretty much avoided the Pike Place Mkt & Pioneer Square areas, bit of a tourist trap & the parking's nuts. An excellent hotel in Portland with a great location is the Heathman heathmanhotel.com/ Haven't been to Mt Rainier (Grove of the Patriarchs), though I've biked on a lot of other trails in the area. Lots of long, converted railway lines great for biking/hiking. Most of the country thinks all it does in the PNW is RAIN! Nope (tho we keep telling everyone that, keeps the riff-raff out ;-)! Summers are generally dry (too dry with the wildfires, these days), rarely over the mid-80's with low humidity and lots of SUN! You might also consider a ferry trip over to Port Townsend on the other side of the Sound. Very interesting area. I love WA, tons of natural beauty, and perhaps the most progressive state in the union, which is important to me. Some other interesting things in Seattle are the Burke Museum, Museum of History & Industry, and the Museum of Pop Culture, particularly the building itself, designed by Frank Gehry. Waterstreet Cafe & Bar in Olympia (Oly, as we call it) is supposed to be good, though I've not eaten there personally waterstreetcafeandbar.com/ Love to hear how your trip goes!


Thank you for your suggestions! I'm adding several to our itinerary. It's so great to get a local's insight when traveling. The weather sounds wonderful. I can't wait. Summer in DC is so hot and humid you can practically drink the air. I always feel sorry for all of those sweaty, red-faced tourists dragging their families from monument to monument in 98 degree heat. Fall is the best time to visit Maryland and DC.


I grew up in central Ohio, I know what you mean about hot & humid! The area had about 3 days of non-hideous weather in the fall, rest of the year was either rain (often accompanied by thunderstorms, power outages, and tornadoes, all of which are extremely rare in "rainy" western WA) the awful heat/humidity of summer, or snow. Definitely hated the heat season most, used to look forward to breaking out the snow blower, because at least it meant the HEAT was gone for awhile. Closest I've experienced to ideal weather would probably be the CA central coast. Are you going any further south than Portland? Another good source of event info etc. in Seattle is "The Stranger", thestranger.com/ a bit edgier. One of their writers is Dan Savage, who's a frequent guest on "Real Time with Bill Maher." Here's another good Seattle Museum fryemuseum.org/ admission's free, or was last time I was there a few years ago.


It is estimated, in the UK , that between 10- 12% of the population has B12 deficiency, the main cause being Pernicious Anaemia. I doubt the statistics in the USA would prove to be different.

Here in the UK, a B12 deficiency would usually mean 6 injections aver the course of a month (loading doses) then 1 every 3 months (maintenance doses)- a regime that seems dissatisfactory to the point of detriment to many many people, but one we have been stuck with for far too long. Now, guidelines tell us, 2-3 months, which gives GPs some leeway. Not nearly enough for many. And many GPs seem entirely unaware that guidelines have changed.

So here we stand, currently.

Guidelines in the UK also say that IF neurological symptoms are present, injections should be every other day until no more improvement is possible. This is a very difficult one because it is unclear to GPs what constitutes a neurological problem, and who is to decide when further improvement is possible ? Likelihood is that a GP would call it quits way before a patient is willing to accept that they'd reached the end of the line as far as improvement goes. Restitution (regaining what's been lost) may be further still down the line. How long do nerves take to heal, assuming they are going to ? Is it the same for all of us ? Unlikely.

Pernicious Anaemia appears to be a "Holy Grail" diagnosis here, and the medical profession seem far more comfortable saying "B12 deficiency" without giving a reason. Perhaps it is the word "pernicious" that frightens them. Cynics would say that the "injections for life" response to this diagnosis is the more likely bugbear.

This might explain the reticence that leads to the following appalling statistics from the most recent research from PAS on people with a Pernicious Anaemia diagnosis :

17% waited up to 1 year for correct diagnosis

19% waited 5 years

33% waited 5 years or more

4% waited 10 years

14% waited 10 years or more for their diagnosis

44% were originally misdiagnosed with MS/ depression/ ME/ Chronic Fatigue Syndrome

The good news is that there is research being carried out that clearly shows a good reason why some of us cannot survive on the 3- month regime that many in the UK are stuck with (and having to resort to self-injection just to be able to stop deteriorating)- and the Pernicious Anaemia Society are responsible for initiating this research. I suggest you join this Society in order to follow this progress.

Meanwhile (could be a long wait before changes) - I suggest doing the following:

Keep list of symptoms (for yourself, for your future, for GPs or consultants) and record severity and frequency daily.

Ask for copies of blood test results. If unsure what they mean, post results with units of measurement and range given by lab. Leave out personal details: yours and medical ones. Check direction of travel as well as what is barely in-range (top/ bottom) because these can make a difference.

GET A REASON for deficiency. As you can see, that may take some time so push for it.

Keep in touch and best of luck. Don't give up, okay?


Thanks Cheryl! I am trying not to give up, though I have to be frank and say that after 40 years of this with zero help from medicine, standard or alternative, it's a bit hard not to get depressed. Especially given that's another symptom...

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When you say you feel like *, do you have any symptoms ?

Have you had a blood test which at the least includes levels of B12, Iron and Folate.

If you have PA or low B12 you will have symptoms and there’s quite a long list of them, you can have a few from that list or a lot from the list.

Google for a list of B12 deficiency symptoms.

It’s an odd time of the night here in UK so I’m giving you a quick reply.

Will get back to you.


I'm in Oregon. I did once monthly, then once weekly injections here in clinics (after relying only on oral ssuoplementation ). For several months now I've self injected every few days. I order from a clinic in BC. Great customer service and quick shipping to me here. I got their info from someone's post on this site.

I was paying $25 per injection at clinics here. With ordering now from BC, I pay just over a dollar for medication per injection. I can get #100 insulin syringes at Walgreens for under $20. I worked up to my injection frequency which seems to be maybe opposite of what others have done. Sometimes I'll go an extra day or two between injections but so far my limit is 48 hours and at that I feel my best.

Good luck and welcome! It's nice to see someone so much closer to me!!

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I guess I'm lucky, my insurance covers all of my shots without a copay. My doctor told me that it costs him about a nickle for each B12 shot.

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Yes, insurance should cover injections. It takes the right physician AND the right insurance company to agree on injections 3 times a week. Sure would be great if I had all that! And would be great if they paid for the bcomplex and other oral otc stuff too!

Really awesome that you've got a great Dr and insurer!


Thanks, Heather!


b12 deficiency, gut problems and low hemoglobin (which indicates an iron issue).

please read about h pylori. i had a b12 deficiency and demanded my dr. test me for h pylori without any gut pain. all i had was some nausea in that area. However i was exhausted to the point of sleeping 9 hours at night and a daily 3 hour nap and still so very tired.

i was orginally told to take a b complex and a multivitamin, for my b12 deficiency, which i diligently did for 18 months before going back to dr. These totaled 125 mg of b12 daily. my b12 was still low and i was told to double the dosage, which i did not do and i waited another 12 months before going to a different dr.

Once i started b12 injections i felt better but not well and my b12 levels never got very high and kept dropping even though i was getting approx weekly injections and would wait as long as i could, 3-4 weeks, before retesting.

It wasnt until i demanded testing for h pylori and finally got it eradicated (it took 2 rounds of treatment) that i started feeling better but again that took a long time. it apparently took 8 months for my stomach to heal enough to absorb b12 on its own again.

My most recent b12 test came back in 1300's which was happily shocking because at the time i had not had a b12 injection for appox 7 weeks prior, i just had not felt the need and then realized why.

prior to that my result were usually in 600s after numerous weekly injections and only waiting 3 or 4 weeks to test.


Kimber - Thanks for the reply. I've tried tons of antibiotics in the 10 years I've had the gut thing. Even tried fecal microbial transplant, which was preceded by a barrage of numerous oral antibiotics of virtually every class, followed by a night long laxative gut-prep as is done prior to a colonoscopy, then introducing the inoculant (donor feces) with a very long tube, to get it well up into the colon, once a day for a week. I really thought that would do the trick on the gut aspect of my troubles, but it didn't. What antibiotic did you take which finally knocked out your H. Pylori?


quadrupel therapy: amoxicillin 1000 mg 2X daily and clarithromycin 500 mg 2X daily along with proton pump inhibitor 30 mg, also 2X daily and pepto bismal 2X daily. All for 14 days.

Waited 2 months after finished treatment and then retested using the breath test. Wait that long to retest because the antibiotics can beat it back but not completely kill it and it takes awhile for the h pylori to recolonize the gut enough to be picked up by the test.

Also cannot eat, drink (including water) or smoke anything for a minimum of 2 hours prior to testing.

best of luck


Not sure if it's already been mentioned, but might be worthwhile getting your folate and vitamin d checked also.


Have to check the records for folate, I have been low on Vitamin D & iron.


Thanks again to all for the information. Very helpful & I really appreciate it. My appointment is tomorrow morning, I'm going to push vigorously for the series of loading doses to start. I'll post back about the process, fingers crossed!


Hi SouthSounder. Never give up! I am a 60 year old man too. At the end of 2016 l was diagnosed with B12 level of 50 pg-ml. Nearly dead. I can not walk, without balance, pins and needles, great tiredness. That was peripheral neuropathy. I used cane 9 months. First month i got 8 injections. Than i read this forum and understand that is not enough. I began self shots every other day. Still now i have more than 360 shots. I am not medically trained but i think i know more than many doctors. Now i am much better and i am playing tennis on court once a week. Keep the hope and self inject. Wish you all the best!


Hi there,

I hope you are feeling better. I was told that too much B12 is as dangerous as too little, and causes the same neurological symptoms. Good luck to you.



I have had PA 13 years and lack intrinsic factor. I am 56 years old.

Originally ny B12 was so low I had daily injections for 6 days, then weekly for 6 weeks and because my GP had the condition herself, she allowed me to self inject and recommended 8 weekly. The maintenance dose according to my GP is 12 weekly and he advised the levels will be sustainable and cannot run too low within the 12 week timeframe.

I hope this helps. Tiredness isn't always cured with regular injections. A good diet with loads of spinach, plus rest and exercise and good sleep helps too.

Good luck.



Hi David, I was only diagnosed at 54 yrs of age, and that was 2 months ago.

I felt tired and jittery at first, and put it down to lack of hormones. It all happened in March after having gallbladder out and pancreatitis. I wonder if the repeated gallbladder attacks damaged my intrinsic factor enzyme in my stomach. I have also been told that drinking any alcohol washes out B12 from your system, so I have limited the intake.

I am not vegetarian, but am not big on meat, fish and dairy, particularly beef, milk and yoghurts etc. If your intrinsic factor is damaged then you definitely need injections.

I suddenly started having heart palpitations 3 weeks ago, and they discovered the B12 tablets were not absorbing into my system, so I have had 5 injections in the last 2 weeks.

I feel a lot better already, and my heart has calmed down. I actually feel quite normal, and will be having 1 injection every 3 months for the rest of my life.

This is such a common disorder; especially as we get older. have the injections and then take control of the rest of your life and enjoy x. Good Luck...



one other thing...

Only take what the Doctors give you, and don't be tempted to overdose on B12 through supplements etc, as I was warned you will feel the same neurological symptoms with too much in your system as too little.


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