Metformin (brand names Glucophage, Glucophage XR, Fortamet, Riomet, Glumetza, and others) is a popular and highly effective oral diabetes drug used to help manage Type 2 diabetes. This drug works by lowering the amount of glucose made by the liver and by making the body’s cells more sensitive to insulin. Metformin also has some other beneficial effects in that it may help lower blood lipid, or fat, levels (cholesterol and triglycerides) and can, in some people, promote a small amount of weight loss.
Metformin can be used with other diabetes pills and with insulin. Side effects of taking metformin are relatively rare, the most common being bloating, nausea, and diarrhea, all of which are temporary. Some people shouldn’t take metformin, including people with kidney disease, liver disease, or congestive heart failure, for example, because of an increased risk of a potentially fatal condition called lactic acidosis.
In recent years, there’s been some concern over the risk of vitamin B12 deficiency in people who take metformin. Vitamin B12 (also known as cyanocobalamin or cobalamin) plays many important roles in the body, such as keeping your blood cells and nervous system in tip top shape. There’s also some evidence that vitamin B12 may help prevent heart disease and possibly even Alzheimer disease (the jury is still out on this one). This vitamin is found primarily in animal foods, such as beef, seafood, eggs, and dairy products, which is why some vegetarians are at risk for a B12 deficiency. Elderly people are often at risk for deficiency as well, due to problems with absorption from the gastrointestinal tract. Symptoms of B12 deficiency include certain types of anemia, neuropathy, memory loss, confusion, and even dementia.
So, why would taking metformin possibly put you at risk for a B12 deficiency? According to some studies, between 10% and 30% of people who take metformin on a regular basis have some evidence of decreased B12 absorption. Researchers aren’t quite sure why this happens. In a study recently published in the October 9 issue of the journal Archives of Internal Medicine,155 Chinese people with Type 2 diabetes taking metformin were identified as having a B12 deficiency, regardless of factors such as age or body weight. The study found that the longer a person had been taking metformin and the higher his daily dose of the drug, the greater his risk of developing B12 deficiency.
The authors of the study advocate consideration of vitamin B12 deficiency screening for people who take metformin. While this screening isn’t routine, it’s worth it to have a talk with your health-care provider to see if you’re at risk for deficiency, especially if you’ve been taking metformin for several years or take a high dose. Also, if you have any of the symptoms of B12 deficiency mentioned above, particularly those related to neuropathy (numbness, pain, or tingling in your hands or feet), be sure to let your physician know. He or she can check the level of vitamin B12 in your blood.
Vitamin B12 deficiency can be treated with either oral, injected, or inhaled forms of B12. Some people, such as strict vegetarians or the elderly, may need to take supplements or receive injections on a regular basis. B12 is found in most multivitamin supplements, so it doesn’t hurt to take a multivitamin as a safeguard. However, avoid taking a B12 supplement unless your doctor has prescribed them. Too much vitamin B12 may be harmful, and B12 can also interact with certain medicines. Always let your health-care team know about all medicines and supplements that you’re taking at each visit.
I m using Vitamin b12Patch to overcome the lack of energy. I was experiencing Fatigue and was feeling stressed out. So I started using this patch. It is required to apply on specified body part. Not required to be injected into the body.
Posted by Gabriel | Feb 07, 2007 at 12:56 pmYou can not take to much B12. Its water soluable and any extra is eliminated by your kidneys through urination.
Posted by Carla | Oct 28, 2007 at 1:43 amCarla,
It’s true that vitamin B12 is relatively harmless, as it is a water-soluble vitamin. However, there have been a very small handful of studies linking B12 excess with prostate cancer. B12 injections can cause allergic reactions and mild diarrhea in a small number of people. Taking large doses of B12 along with vitamin C may lead to nosebleeds. The point is that taking large doses of this or any other vitamin, mineral or supplement probably isn’t a good without medical supervision.
Posted by acampbell | Oct 29, 2007 at 2:48 pmWhat information has Bristol Myers Squibb provided to physicians on this matter, if any. Are they taking any efforts to proactively getting this information into the hands of us who take this drug?
Also, I have read that normal tests for B12 levels may not disclose that patients are deficient in B12 as it does not disclose that the problem may be malabsorption.
Are there any studies that indicate Metformin decreases the bodies ability to properly utilize B12 even if it is at adequate levels? Sort of like being insulin resistant except being B12 resistant.
Finally, is Bristol Myers making any proactive attempt to have physicians test specifically for B12 in patient with a long history of metformin use?
Posted by sh10492 | Jan 06, 2008 at 10:01 pmHi sh10492,
I’m not aware of any particular campaign on the part of Bristol Myers to inform physicians on the potential risk of B12 deficiency with metformin use. However, there is mention of this risk in the package insert for Glucophage/Glucophage XR, and it’s recommended in the PI that those at risk for deficiency be screened at 2-3 year intervals. Apparently testing for methylmalonic acid (MMA)over blood B12 levels is recommended by some, but it’s use is still somewhat controversial in the medical community. One theory is that metformin may interfere with B12 absorption; however, it appears that supplementation with 1000-1200 mg of calcium can limit this interference with B12 absorption. As I mentioned in my posting, it’s important for anyone taking metformin, particularly long-term, to talk to his or her healthcare provider about the potential risk for B12 deficiency and the steps one can take to prevent this from happening.
Posted by acampbell | Jan 09, 2008 at 9:11 amThank you for the commenting on my questions.
I find the package insert to be insufficient. It indicates that paitients should be “predisposed” and testing “may be useful”.
Given the rates of 30% B12 deficiency it would seem (from a layman’s point of view) that taking the medication predisposes one to the deficiency and knowledge of the deficiency would be MORE than useful.
Posted by sh10492 | Jan 09, 2008 at 1:57 pmI was just wondering if it is harmful to take a vitamin B-12 plus prenatal vitamins daily. I am not pregnant, I just thought it would be good to take the prenatal vitamin for the extra vitamins.
Posted by msmith | Jan 10, 2008 at 8:51 pmHi msmith,
There’s very little risk in taking a B-12 supplement. However, I’m wondering why you’re taking a prenatal vitamin, given that you’re not pregnant. Prenatal vitamins contain more folic acid, iron and calcium than regular multivitamins. Unless it’s been advised by your physician, I’d suggest switching to a regular multivitamin and focus on getting the remainder of your vitamins and minerals from food sources.
Posted by acampbell | Jan 15, 2008 at 4:17 pmI have now been taking Vitamin B12 for 24 days. In that time my insulin requirement has gone from 60-65 units to 15-20 daily. I still take Metformin and now take 2000mcg of B12.
My energy level has skyrocketed.It seems my mental cognition and memory have also improved.
Unfortunately many of the symptoms of B12 depletion mimic diabetes complications. I have been suffering from this depletion for at least 4 years and just learned to cope until I hit a wall and suffered many health consequences. It got so bad that in December I had decided to claim my disability insurance as I had no hope of maintaining a 40 hour work week.
Four days after taking Vitamin B12 I began to feel better. Within a week I felt “Good” for the first time in months.
Lets get the word out about this! Too many people are suffering and the drug companies have done nothing to alert patients and physicians of consequences of metformin and glucophage for long term users.
Posted by sh10492 | Jan 30, 2008 at 9:39 pmHi sh10492,
Posted by acampbell | Jan 31, 2008 at 3:16 pmThanks for sharing this - very encouraging! Hopefully this will encourage people who take metformin to have a discussion with their provider about a possible risk of B12 depletion.
I have diabetes type two but was not diagnosed long after it should have been
Posted by C.J.COOK | Feb 29, 2008 at 4:41 pmi can not eat because i do not digest food
and so i thought if i could take B-12 Sublin
gual which would go under the tongue and dis
dissolve and quickly enters the blood-stream.
Hi C.J.,
Posted by acampbell | Mar 03, 2008 at 1:40 pmYou can certainly take B12 sublingually. You may want to check with your physician as to what dose would be approriate for you. For people who haven’t had a source of B12 for a while, a starting dose might be 2000 micrograms daily for a couple of weeks, for example, then tapering down to once a week. For people with deficiencies or other medical issues, B12 injections might be needed. So talk with your physician as to what method and dose would be best for you.
HI ,,,,
CAN I TAKE VITAMIN B6 AND B12 BOTH OF THEM TOGETHER ON THE SAME TIME ,……….
IF SAFE IF I TAKE 200 MLG OF B6, AND
2000 MCG OF B12…
WHAT is the right dose……
CAN I TAKE B6 AND B12 IF I AM TAKING FUROSEMIDE 20 MG ONCE A DAY ,
Posted by YL | Apr 01, 2008 at 12:46 pmPLEASE IF SOMEBODY CAN HELP ME…
THANK YOU
Hi YL,
Posted by acampbell | Apr 01, 2008 at 1:46 pmYou can take B6 and B12 together. Also, furosemide may slightly deplete these two vitamins, so it’s okay to take them with this medication. You may want to take your vitamins with or after a meal. However, you’re taking fairly high doses of B6; the RDA is 1.3-1.5 mg for women, and the upper limit is 100 mg/day. Too much B6 can be harmful. Also, unless you’re deficient or have a malabsorption disorder, you don’t need 2000 mcg of B12 (anywhere from 1-25 mcg would be okay). I’d suggest you talk with your physician about doses that are best for you.
thank you so much for you advice….
Posted by YL | Apr 02, 2008 at 1:04 pmyou really gave me a peace of mind….
This is such an interesting discussion. I was diagnosed with Pernicious anemia as my B12 levels were very low. My Mother and her six sisters also had pernicous anemia as does my older (and only) sister. I am having a b12 injection monthly, but I really feel I need it three weekly as the last week I am so lethargic I can barely move. I have type 2 diabetes and am taking 2000 mg of Metformin daily. I had never heard of the link between the two.
Posted by Karen | Apr 05, 2008 at 12:16 amHi, I took Metformin in 2005 and stopped taking it after 18 months without telling my physician, I was prescribed to take a total of 2500mg/day for my PCOS, that’s 1000mg at breakfast, 500mg at lunch and 100mg at dinner. I was advised by my physician to take it on a gradually increasing dose which I did. The reason why I stopped taking it was due to being sick of urgently needing to go the toilet every after meal and it’s always been loose. After reading your blog, I realised that I may be lacking in B12 when I was taking Metformin as I also get fatigued easily and I became forgetful. The last time I took Metformin was 2 years ago. Now that I just saw another physician, he advised me to start taking Metformin again as it will help my PCOS, but this time, I was only prescribed to take 500mg three times a day. The next time I see my physician I will ask him to check my B12 levels.
Posted by HoneyNZ | Apr 06, 2008 at 9:27 pmI have started getting White hair rapidly. I surfed the web and got the info that its most likely due the deficicency of Vitamin B12. 1). Can you kindly discuss this please? No matter how brief your kind suggestions are. 2). Are vitamin B12 tablets are under non-subscription drugs? i mean should i need to have Doctor’s letter to buy these pills? 3). which one is the best product for these pills? Will highly appreciate for your kind suggestions. Thanks!
Posted by kashif | May 17, 2008 at 5:34 pmHi kashif,
Posted by acampbell | May 19, 2008 at 10:07 amI’m not a hair expert, but please keep in mind that there are many causes of white or graying hair, including family history, age, gender and illness. Pernicious anemia, resulting from a lack of vitamin B12, may also be a cause. However, you should discuss this possibility with your physician before concluding that you’re deficient in B12 and before you start taking B12 supplements. B12 is available without a doctor’s prescription, but, again, please discuss your concerns with your physician to rule out other possible causes of your white hair.
I was on Metformin a few years ago and had to stop…after 3 months, I was still vomiting and having horrid bowel movements. My doctor retested me and stated that my previous doctor (the one that prescribed it) might have been over cautious as I had no sign of high blood sugar or triglycerides. However, because of PCOS they recommend that I might want to start taking it again as I am trying to conceive. What do you think? Can and should I take this while taking the prenatal vitamins? I worry about the constant nausea I had previously.
Posted by tenorsaxgyrl | Jul 02, 2008 at 11:38 pmHi tenorsaxgyrl,
Posted by acampbell | Jul 03, 2008 at 11:34 amGastrointestinal side effects occur in up to 1/3 of people who take metformin. Given your previous side effects with this drug, you should talk to your provider about ways that you might prevent them from occuring again, or at least minimize them. Some suggestions are to start with a very low dose and gradually build up; take your metformin with meals; and limit rich, fatty meals. I’m not aware of metformin interacting with prenatal vitamins. You can always try metformin again and see what happens. Obviously, if you still get extreme side effects such as nausea, vomiting and diarrhea, metformin probably isn’t for you.
when they check for the b12 deficiency do they do a CBC or a specific B12 test?
Posted by live4fitness | Jul 23, 2008 at 3:48 pmHi live4fitness,
Vitamin B12 levels are measured, often along with folate (another B vitamin) as a separate blood test. A CBC, or complete blood count, may indicate the presence of large red blood cells, which would then prompt your provider to order a separate B12 blood test.
Posted by acampbell | Jul 24, 2008 at 8:21 amI took metformin for about a year and it also gave me constant diarrhea. Because of the diarrhea my sodium and magnesium are low and haven’t been able to correct the levels yet. I also have a B-12 deficiency, i have been taking shots for almost a year and still my levels are low. My doctor recently said that was enough of the metformin because it seem to do more harm than good, she now has me on a diabetes med called januvia. I have been on this medication for about 3 wks and I haven’t had has much diarrhea. I wondered if the diarrhea from the metformin is what caused my B-12 to be low also.
Posted by superwoman | Jul 27, 2008 at 9:37 pmWHEN TAKİNG METFORMİN AND B1 VİT TOGATHER does it
RESULTS İN HAVİNG LACTİC ASSİDOS.
THANK YOU FOR YOUR HELP İN ADVANCE.
FAY SEBENE/Mr.
Posted by FAY SEBENE. | Jul 28, 2008 at 8:15 amHi Fay,
Posted by acampbell | Jul 29, 2008 at 8:12 amNo, taking metformin with vitamin B1, which is thiamine, does not cause lactic acidosis. Lactic acidosis is a very serious condition whereby lactic acid builds up in the blood. Symptoms include loss of appetite, nausea, vomiting and abdominal pain. It most often occurs in people with kidney or liver disease, or in people who have tests involving injected dyes, or after surgery. If you take metformin and are scheduled for any kind of radiologic test or surgery, you may need to temporarily stop taking your metformin, so check with your physician for instructions.
Hi superwoman,
Posted by acampbell | Jul 29, 2008 at 8:44 amIt’s possible that the diarrhea you’ve had caused a B12 deficiency; however, it’s probably more likely that the metformin itself was responsible. Fortunately, your diarrhea has resolved and hopefully your B12 levels will return to normal soon.
i was recently diagnosed with pcos and am taking metformin (850x daily) along with synthroid for low thyroid. We hope to try to have kids in the next year or so and I have been taking pre-natal vitamins. I saw your previous post about them, should I not be taking them with metformin and synthroid?
Posted by meridith | Aug 21, 2008 at 3:09 pmHi Meridith,
Posted by acampbell | Aug 22, 2008 at 3:40 pmYou might try taking your prenatal vitamins separately from your metformin. Also, it’s probably a good idea not to take your vitamins with your Synthroid, as the iron may decrease the absorption and action of your thyroid hormone.
I just turned 35 and in the past year have been having multiple issues including muscle tenderness/tingling, lack of focus, inabilty to sleep the night and light headedness. I may have had these issue in the past off and on, but recently I have been more focused on them as I get older. My sister told me I may be B12 deficient, since we are both Type A+/O+ blood type. Her doctor told her that this combination traditionally is deficient in B12. Does this make sense or is it a possibility?
Posted by MG | Aug 29, 2008 at 1:11 pmI am 72 years old and am a type 2 diabetic. For 5 years I have been taking Metformin 500 x 3 times per day. Tingling/numbness in my feet, pains in legs and ankles also swelling (possible odema) weight gain and general tiredness when walking and I have made an appointment with my GP to discuss these problems re possibility of a B12 deficiency. Apart from my age, would you agree these symptoms could be linked to this type of deficiency? Any comments would be so appreciated. Thank You.
Posted by Jillybean | Aug 29, 2008 at 3:48 pmHi Jillybean,
Please realize that I’m not a physician and cannot diagnose anyone. However, some of your symptoms could be consistent with a B12 deficiency, including the tingling and numbness in your legs, and your fatigue. Weight gain and swelling are usually not linked with a B12 deficiency. I’m glad to hear that you’re going to discuss your symptoms and possible causes with your physician.
Posted by acampbell | Aug 31, 2008 at 5:33 pmHi MG,
Posted by acampbell | Aug 31, 2008 at 5:43 pmI’m not aware of a particular blood type being linked to B12 deficiency, but I suppose that could be a possibility. The more common causes of B12 deficiency include insufficient intake, malabsorption disorders, such as Crohn’s disease, certain types of abdominal surgery, parasites, pernicious anemia and aging. You really should discuss your symptoms with your physician to rule out other possible causes for your symptoms.
I have been experiencing Menieres symptoms for the last five years. In the past two years, I have noticed a rapid progression of vertigo, ataxia, a feeling of falling, and positional problems. Two days ago I started taking a protein powder and vitamin supplement and yesterday I had the first vertigo free day in years. I began to wonder if I might have a vitamin deficiency, and this morning have discovered a possible link between my metformin, vitamin b12 deficiency, and ataxia. I may be grasping for straws, but do you think that there might be a connection?
Thanks
Posted by rosdonald | Sep 04, 2008 at 8:34 amRose
Hi Rose,
Posted by acampbell | Sep 05, 2008 at 11:59 amNot being an expert in Meniere’s, I’m a little skeptical that the improvement in your symptoms is due to the vitamin and protein supplements that you’ve started, particularly after being on both for such a short time. I’m not aware of specific vitamins that have been linked with Meniere’s. But, if you’ve been on metformin for a while, it’s possible that you’re deficient in B12. Ask your provider at your next appointment to check your B12 level. Also, I’d suggest you go easy with the protein powder; most people don’t need additional protein, unless they are ill, have undergone surgery, or follow a strict eating regimen that might restrict protein.
Thank you so much for your response, just to clarify….does that mean I should not take prenatal vitamins at all with metformin and synthroid or just that I should space it out and take the vitamins at a different time in the day than when I take my meds?
Posted by meridith | Sep 11, 2008 at 9:52 amHi meridith,
I’d recommend you take your vitamins at a separate time from your medications. It’s fine for you to continue with your vitamins AND your meds - just take them apart from each other.
Posted by acampbell | Sep 11, 2008 at 2:51 pmThank you so much for this discussion! I was wondering if the metformin/B12 deficiency link was as strong when taking Janumet? I have not been tested for B12 deficiency (but plan on discussing that with my doctor soon) but have been suffering from nausea and lightheadedness for the past week. I’ve been on 50-1,000 mg of Janumet twice a day for 2 months now, and was on metformin for 1 month before that. Also, I had my son 5 months ago and I’m not sure if that’s even a factor, if my body is not quite back to normal yet.
Posted by libelula | Sep 25, 2008 at 7:09 pmHi libelula,
Posted by acampbell | Sep 28, 2008 at 12:33 pmIt’s certainly possibly that a B12 deficiency could occur when taking Janumet (a combination of Januvia and metformin), although you haven’t been taking it for all that long, so a deficiency is probably unlikely at this point. Your nausea could be due to the metformin. Please contact your physician soon to discuss your symptoms and possible causes.
I’m 55 yo & have been taking Metformin for almost 10 yrs. I’ve often complained to Drs. about leg pain & feeling exhausted. She tested thyroid - it was ok. Now test came back with low iron & B12. I read about the link to Metformin & asked. She said she hasn’t seen it clinically. Wants colonoscopy to check for internal bleeding. Why won’t Drs. listen to patients?
Posted by Dorothy | Oct 17, 2008 at 4:12 pmHi Dorothy,
Posted by acampbell | Oct 18, 2008 at 4:51 pmDoctors have so much information to keep up with and stay on top of, and it’s very likely that your doctor wasn’t aware of the link between metformin and vitamin B12. She’s being thorough, though, in ordering a colonoscopy for you. What’s often helpful for communicating effectively with healthcare professionals about a particular issue is to bring in a copy of an article that explains the issue; that way, they can do their own “research” (even though it’s frustrating when they didn’t listen to you in the first place!).
Question - i have seen some information that says taking calcium can reverse the b12 absorbtion issue caused by metformin. have you heard that? is there a recommended dose of calcium, or should i check with my doc. thanks. i got my first b12 shot today for b12, anemia issues. i have taken metformin for 10 years.
Posted by bertk523 | Nov 19, 2008 at 12:36 pmHi bertk523,
There is some evidence that taking 1200 mg of calcium (as a supplement) may help limit the effect of metformin on B12 levels. It’s something you could consider trying, although it’s not a bad idea to discuss with your physician, first.
Posted by acampbell | Nov 20, 2008 at 8:09 amI’ve been taking Metformin for 10 years. My current dosage is 1000 mg 2x per day. (the max) About 3 months ago I was diagnosed with a B12 deficiency. It must have been very low, because I had to get a shot once a week for a month, then 1 a month since. I told my physician about the study linking metformin with B12 deficiency and she had never heard of it. I asked about changing to a different med, but I was told that we’ve tried everything else but Insulin. I dont want to go that route unless really necessary If I continue to take the Metformin and the shots will my B12 go back to normal?
Posted by Joanna | Nov 20, 2008 at 6:56 pmHi Joanna,
Posted by acampbell | Nov 24, 2008 at 8:24 amDepending on the extent of your B12 deficiency, it probably will take at least several weeks or even a couple of months to restore your levels. You need to keep on top of your levels until they return back to normal. Ask your physician to periodically check your B12 levels after that, as well. In the meantime, make sure that your diet contains plenty of B12 (taking a multivitamin is a good idea if you’re not already doing so).
Hi, I have been taking metformin for some ten years now .The veterans lab told me my B-12 count was low ,and to take 1000MCG tablets as soon as possible . I have been taking the B-12 for f4ive monthe noe ,a blood test indicated t
Posted by fwman | Dec 29, 2008 at 3:38 pmHi fwman,
I’m not sure what your question is - it looks like it got cut off…?
Posted by acampbell | Jan 05, 2009 at 9:33 amHi I am a user of metformin for ten years now.
Posted by fwman | Jan 11, 2009 at 12:18 pmI am seventy eight ,The veterans admin, told me my b-12 was very low ,and to start takeing100MCG of B_12. Blood test lately said my B-12 was fine .Should i keep on taking the B_12. I feel fine at this time .What do you think? Thanks for your time ,Buck Carpenter
Hi fwman,
It’s good to hear that your B12 levels are back to normal. I’d suggest you talk to your physician about whether you should continue taking the supplement. 100 mcg is a large dose, which you needed in order to correct your low B12 level. You probably don’t need this large a dose anymore, but your physician might suggest that you continue with a lower dose or even take a multivitamin. Also, make sure you know why your level was low in the first place so that you can prevent it from dropping again.
Posted by acampbell | Jan 12, 2009 at 10:00 amMy mother has been on Metformin for 4 years now. She is 75 years old. Today,during my mother’s primary physician appointment I had mentioned to him that I have found that Metformin causes a vitamin B12 deficiency when I researched it on the Internet. I was really looking for any solutions to my mother’s other problem of having a burning feeling from below her knees to her feet (both legs). She is also having memory loss, fatigue, balance problems, constipation, loss of appetite, etc. When I mentioned that since her memory doctor suggested that she have her vitamin B12 checked and found that she was deficient, I told him that Metformin had to be the cause. He never heard of it! He also checked some small book on his desk to see if he can look it up himself. I also had left a message for my mother’s Endocronologist. He just gave me a call and guess what? He never heard of it either. I told him to look it up on the Internet. I had also told him that her memory doctor found that she was deficient in vitamin B12 and so I had to do my own investigation. I did ask for another kind of diabetic pill that my mother could take so she can get off of Metformin. Her primary doctor prescribed glimepiride. Does anyone know if this medication can also cause the vitamin B12 deficiency? I just can’t believe that I had to be my own doctor to help my mother. Everyone is so used to listen to their primary doctors, then when you need to go to a specialist, like getting a second opinion for your primary, you can’t even trust that they are going to be the experts in what they say they are experts it. If this is what our American doctors constantly do, experiment on us, then I suggest that we become our own doctors, do our own research and go back to the natural way of healing our bodies because we are fed up of being ginny pigs for the drug companies and the physicians. I just hope my mother’s B12 levels come back up since she has been getting a monthly shot and also taking 2500 mcg supplement every day. Please also let me know if the 2500 mcg is ok. Thank you.
Posted by Maria | Apr 08, 2009 at 8:47 pmHi Maria,
Posted by acampbell | Apr 12, 2009 at 3:13 pmTo my knowledge, glimepiride doesn’t lead to a vitamin B12 deficiency. I believe that a typical oral dose of B12 to correct deficiency is between 1000 and 2000 mcg daily for 1-2 weeks. The dose that your other currently takes is probably fine for now but she shouldn’t need to stay on that indefinitely, especially since she’s also getting a B12 injection. Speak to her primary care physician about the dosing schedule for correcting the deficiency and then a maintenance dose.
This information is very helpful. My mom has had diabetes for 17 years now. She has been taking metformin for a while. She recently was told she had Vit b12 deficiency and that she needs to have injections to correct this. My question is, why would the doctor order injections and not oral medication? Do the injections work more efficiently?
Posted by worried about mom | Apr 15, 2009 at 3:02 amThank you in advance for you help.
Hi worried about mom,
Oral B12 supplements can be given to correct a B12 deficiency, but the dose would have to be pretty large in order to do so. For this reason, injections are usually given for deficiencies. Also, there is some concern that people may not take the full oral dose, whereas one would receive the right amount in an injection. Up to 30% of adults older than age 50 have difficulty absorbing vitamin B12 in the digestive tract due to decreased levels of hydrochloric acid, so taking an oral B12 supplement would be of little use in this situation (this is a reason that many older adults get B12 injections). Finally, some other medications can interfere with B12 absorption in the digestive tract, including some used to treat peptic ulcer disease and gastroesophageal reflux. So, it’s a good thing that your mother is getting B12 injections.
Posted by acampbell | Apr 15, 2009 at 2:10 pmWoW
Posted by Peacock | Apr 17, 2009 at 7:37 pmA couple of weeks ago I experienced raw sore red tongue. Just all of a sudden it came on. I knew I hadn’t eaten anything different. It continued to get worse. With a few sores appearing inside my mouth. So I started doing research online to find out what is causing this. I do this before I see my Doctor on things. Sure enough I came across the depletion of B12 issue connected to taking Metformin. I mentioned this finding to a Doctor I work with in a clinic. and He said it wouldn’t be that…it had to be something else. I knew he was wrong. So I went out and got B12 2000mcg. Started taking it and in 3 days my tongue was back to normal. Also I noticed no more stinging and numbing on top of my feet…which I was associating with my Type 2. I also made sure that I told that Doctor I work with what I did and how it helped and this would be good info in case another diabetic expereinced it. I also told him to google it to find out I was right.
I will see my regular Doctor in May and tell him about this experience.
I’ve been taking metphomin for about 8-10 years. I’ve had diabetis for 23 years and also take insulin 70/30. I also suffer from gastro problems since I was a child and take medication for acid reflex. Recently my Endo prescribed Byetta because I’m my pancreas are becoming insulin resistant where I require a lot of insulin. I had to be admitted into the hospital for observation because I was having fast heart beats and fainthing spells. They did all types of test and the only thing the doctor found was low levels of B12 that he could not understand why. He sent me home with a prescription of B12 shots but never mentioned anything about metphormin. I am now taking 600mg of calcium when I take my metphormin. Does that sound ok.
Posted by gl52 | May 03, 2009 at 6:04 pmHI gl52,
Unfortunately, many healthcare providers aren’t aware of the link between taking metformin and vitamin B12 deficiency. However, the good news is that you’ll be getting B12 shots and taking calcium. Be sure to follow up with your doctor and find out when you should get your B12 level checked and what the result it.
Posted by acampbell | May 04, 2009 at 1:14 pmThank you so much for this post. I have been taking Metformin 2000 mg per day for 8 years now for type 2 diabetes. I had lots of tingling and pain in my feet that was diagnosed as neuropathy. I got tested recently for B12 deficiency and started getting B12 shots. What a wonderful difference. The constant pain in my feet has stopped and I have more energy. The plan is to continue to get the injections and test again to make sure the B12 in my body is increasing.
Posted by Deb | Jun 29, 2009 at 1:42 pmHi GL52, i have a similar history to yours and also have taken metformin for 8 years, but I want to address your comment about Byetta. I also had fast heartbeat and fainting when I took Byetta. My gastroenterologist believed that Byetta was increasing my gastro problems because it slows the emptying of the stomach. After discussing it with my endroconlogist, I stopped taking Byetta and started using Humalog along with some 70/30 in the am and pm and the heartbeats and fainting got better. I still found that my B12 was low and as I mentioned in the last note, I started getting B12 injections and the neuropathy pain in my feet has subsided.
Posted by Deb | Jun 29, 2009 at 1:49 pmMy mum has been suffering a fairly rapid weakness in her legs and now 3 months later and barely able to walk and using a frame she was told she had motor neurone disease. The family were devestated. As far as we know this diagnosis stands however she was told a few days ago that she has Vit B12 deficiency and after reading about it on the web, the symptoms fit all of hers. She is on metformin and has been for about 5 years now but we never knew of this side effect and it seems neither did her doctor who was still puzzled as to the cause of this neuropathy. We are all very hopeful that with injections of Vit B12 her weakness will begin to resolve. I wish we had known earlier about this and even more so I wish her general practioner did too.
Posted by kate donegan | Aug 17, 2009 at 9:27 amHi Kate,
I certainly hope that the B12 injections help to resolve your mother’s leg weakness. It’s great that you informed her doctor about the link between metformin and B12 deficiency, too.
Posted by acampbell | Aug 17, 2009 at 11:24 amhi - i just wanted to share my experience and knowledge regarding b12 deficiencies.
pernicious anemia in and of itself is not the same as a b12 deficiency, although a b12 deficiency is a symptom of pernicious anemia and is often the determining factor for the diagnosis of pernicious anemia. while the differences are subtle, a b12 deficiency alone has less to do with blood (anemia) than with the body’s inability to absorb the vitamin from the GI tract. (for example, the CBC test would actually come back as normal, but the b12 would test low - b12 deficiency. if the CBC came back abnormal AND there was a b12 deficiency, then that points to pernicious anemia because it is blood related.) it hardly makes a difference, really, but it is interesting to know exactly why one has a b12 deficiency - malabsorption or anemia. the treatment would be the same - most likely b12 injections.
i have been on metformin 500mg 2x/daily for over 4 years to treat PCOS. i am not trying to get pregnant, but the other conditions that PCOS can cause (facial hair, insulin resistance, Syndrome X) are be helped with this medication.
two years ago, after a surge of migraines and fibromyalgia-seeming symptoms, i was diagnosed as having a severe b12 deficiency - which my doctor and i both feel were the culprit of the increased migraines and nerve pain. my doctor did not make the connection with the metformin use at first (apparently it is a rather new discovery/link), but after discussion he advised that the small dose i am taking would probably not be the cause. in the end, we decided together that i get a great deal of benefit from metformin, and the b12 injections are not too much of hardship, so i am staying on metformin and now having one b12 shot a month (in the beginning it was one every week, then as the level in my body began to rise and sustain, the frequency has been decreased). to date, my body has not yet been able to retain a sufficient level of b12, thus the continued injections.
also, while taking a b12 supplement is a good idea, remember that if malabsorption is the problem, an oral tablet of b12 will not be absorbed by the body anyway - a sublingual tablet has more of a chance since it is not absorbed through the GI tract, but passes into the bloodstream under the tongue. injections put the b12 right into bloodstream so it is immediately available to the body. additionally, the dosing available in an injection is considerably higher than what an OTC vitamin supplement can provide, so it may be necessary to maintain injections to get the b12 level up, then try to supplement with a pill.
i am not a doctor, but i am a healthcare professional. this post is to be taken as discussion only and not any medical diagnosis or advice. talk to your doctor if you have concerns about your b12 deficiency, pernicious anemia and/or your concerns about metformin use.
thanks!
Posted by Kim | Sep 08, 2009 at 5:44 pmHey,
I’ve been diagnosed as a type 2 diabetic 8-18-09. I just turned 40yrs old in August..
I started on 500mg’s of metformin and my level was at 353 and came down to the 200’s in 3 weeks. My doctor says I’m not down far enough. So they upped my dosage to 2 times a day and then 3 times a day. I was wondering about this aching and pains in my legs and abdominal area. I also have the tingling in my fingers and numb big toes.. I’m glad I read this postings cause now I think I see why. I went out and purchased b-12 (1000mgs)yesterday and started … hopefully it makes me feel better and kills these aches and numbness. My level is at 125 now since the 3X a day metformin. I really have trouble sleeping because of the uncomfortable aches and pains.. I take many hot baths to soothe the pain and then it comes right back,, temporary relief is better than nothing …whew.. Hopefully the b-12 helps out. I’ve only taken one dose. Maybe in a couple days-weeks.. I’ll be back with a feel better story of my own.. wish me luck
Posted by Jay | Sep 21, 2009 at 4:10 pmHi Jay,
At the American Diabetes Association Scientific Sessions this past June, researchers presented a study that looked at vitamin B12 deficiency in people with Type 2 diabetes who were taking metformin for at least one year. They found that more than 75% of the metformin users who had low B12 levels also had peripheral neuropathy. There’s not enough evidene from this study to conclude that the low B12 levels caused or contributed to the neuropathy, but it does reinforce the need for people who take metformin to have their vitamin B12 levels checked. I do hope you’ve told your doctor about your pain and the fact that you’re taking a B12 supplement. Pain is always a cause for concern and you should let your doctor know to rule out other possible causes. And, if you truly are deficient in vitamin B12, your doctor can recommend the appropriate B12 dose for you (I assume you’re taking 1000 micrograms [mcg], not milligrams [mg]).
Posted by acampbell | Sep 22, 2009 at 8:32 amYes.. Micrograms is correct. I will let the doctor know today. I haven’t contacted her yet. Its crazy when you will try anything to feel better these days. I’ve never been the one who visits the doctor’s office often. Now i’m always there. I’ll go ahead and stop taking the vitamins til I get word from my doctor. Thanks for the feedback
Posted by Jay | Sep 24, 2009 at 9:57 amI take an extra strenght Great Earth “TNT” multivitamin which contains 75 mg of all the B vitamins including 75 mg of B12. Not 75 mcg, but 75 mg. The daily percentage contained in this vitamin for B12 is listed on the bottle as 1,250%. Is this OK to take without side affects? All the B’s are in the 2-3,000% daily range with this multivitamin. Is this normal for a multi-vitamin?
Posted by Pat | Oct 30, 2009 at 12:12 amHi Pat,
I’m not really sure why you need to take such a potent multivitamin. You’re getting way more than the recommended daily allowance of these vitamins, and there’s not a lot of evidence that taking this much is helpful. Large doses of vitamin B12 are likely not harmful, but more than 100 mg per day of vitamin B6 may lead to nerve damage, and 50 mg or more of niacin may cause flushing. There’s also some evidence (not conclusive yet, though) coming out that more than 1000 micrograms per day of folic acid may increase the risk of cancer. While you’re not getting this amount in the vitamin, you are (I’m assuming) getting these vitamins from food sources, too. In general, taking a multivitamin that provides no more than 100 to 150% of the RDA or Daily Value of vitamins and minerals is your best bet.
Posted by acampbell | Oct 30, 2009 at 10:19 am