Why Isn’t Metformin Prescribed More?

Since its debut in the United States in 1995, metformin has become the most popular oral drug for Type 2 diabetes in the country — and the rest of the world. Current guidelines by the American Diabetes Association state that unless there are special risks in a particular person, metformin should be the first drug prescribed to people with Type 2 diabetes. Yet perhaps due in part to its popularity, metformin isn’t free of controversy. As we’ve discussed previously here at Diabetes Flashpoints, there are concerns about prescribing metformin in people with kidney disease, and some doctors even question whether metformin deserves its status as the universally recommended first-line drug for Type 2 diabetes. In addition, there’s debate about whether metformin should be taken by more people with prediabetes.


A recent study sought to explore the reasons why metformin isn’t prescribed as widely as clinical guidelines suggest it should be. Published last month in the journal Therapeutic Advances in Chronic Disease, the study notes that only roughly 65% of people with newly diagnosed Type 2 diabetes are prescribed metformin — and that over time, this number drops to just 25% of people with the condition. As noted in a Pharmacy Times article on the study, researchers from the University of Colorado put together focus groups of relevant people — doctors, pharmacists, and other medical personnel — to ask about their perceptions regarding metformin.

Based on these focus groups, the researchers found that three main factors affected how doctors prescribed metformin: concerns about when to start the drug, concerns about the drug’s known risks, and whether procedures were in place to notice and deal with any adverse reactions caused by the drug.

Based on the focus groups’ responses, the researchers concluded that overall, perceptions about the risks of metformin weren’t based on the latest research and clinical recommendations — especially when it came to the risk of lactic acidosis (a very rare but serious side effect of metformin and certain other drugs), as well as how compatible the drug is with kidney disease, heart failure, liver disease, or alcohol use. When the latest evidence was discussed with members of the focus groups, some participants shared that their attitude toward prescribing metformin had changed. This led the researchers to conclude that certain education efforts — including distributing information, but also incorporating guidelines into tools for electronic prescribing — could lead more doctors to prescribe metformin to more patients, in accordance with clinical guidelines.

What’s your experience with metformin — do you take it, or have you taken it in the past? Is it the first drug that your doctor prescribed for your diabetes? If you no longer take it, why? Did you experience any unpleasant reactions or side effects from the drug? Do you think it’s important for doctors to follow clinical guidelines for prescribing drugs, or should they let their own experience be their guide? Leave a comment below!

Learn more about the health and medical experts who who provide you with the cutting-edge resources, tools, news, and more on Diabetes Self-Management.
About Our Experts >>

  • T2DM

    Metformin can cause Vitamin B12 deficiency. Recently, Vitamin B12 deficiency has been linked with Alzheimers. The real question is why aren’t more physicians promoting eating reduced carbs, 130 g or less per day, to all their Type 2 patients? Full lipid panel, try less carbs, retest after 3 months and look at the triglycerides. That kind of visible success was very motivating for me.

  • Mumbro Oz

    I was on 3 x 1000mg of Metformin for over 5 years then was put on Januvia because of badly controlled T2D. I started LCHF Diet November 2015 and stop Januvia and Metformin within a couple of days and have had good control without medication ever since. I did not have any trouble whilst taking the medications other than I was always hungry and constantly battling to control appetite and weight gains. LCHF has dramatically improved my life and I believe my beta cell function.

  • Scott Beveridge

    I was taking Metformin for a few months when I was first diagnosed with Type 2. By changing my diet and exercise habits I was taken off Metformin and now take no diabetes medicine. Diet and exercise is key. While on Metformin I did not have any issues with the medicine.

  • Carrie Simmons

    I’ve got a roommate who was accuses of being a alcoholic ands has been on Metformin for 2008. He’s got a multitude of health problems since he’s been on it. He’s got 4 problems out of the problems. Advice is needed it’s not working well and his hospital visit he got MRSA and showed symptoms of damaged kidneys.

    • Angelique

      his alcoholism is the root problem it sounds like? he should not be drinking period and certaintly not when taking metformin.

  • Maris Smith

    I was prescribed Metformin for several years, and during that time, I became so weak it was difficult for me to walk a hundred feet. When I was first prescribed this drug, I honestly felt like I was dying. It made me feel sick and it made me have tunnel vision where my vision would become a pinpoint. I complained and they put me on extended release. My A1c never got under 8 taking this medication. So he prescribed insulin along with the Metformin. The outcome of that was I gained a huge amount of weight, and could not exercise with the insulin because the Metformin made me so weak. I finally refused to take it anymore, and told the doctor I would only take insulin injections. After about a year, my strength returned. I started on a diet and exercise program and have lost 90 pounds. No idea if anyone else had this experience, or these side effects. My A1c is close to 7, and my sugar levels are much easier to be controlled. Even my insulin use has gone down by 80 units a day because of the exercise and weight loss.

  • Shoshana

    Lowered body temperature.

  • azjen

    i was never prescribed with diabetes 2 & yet my doctor prescribed it & told me to take it. The pills gave me horrendous diarrhea & it was so bad that I simply had to quit taking it. Upon seeing my doctor again, I told her of what I had experienced & she said that she gave me the pills so that I could lose weight. Well, I never heard her say that nor did my husband. I am positive that I do not have diabetes 2. My glucose level has been below the normal level. I quit taking the Rx b/c I simply could not tolerate it anymore.

  • Popeye

    Used to have the same problem but it stopped when I went to metformin ER (extended release).

  • DesertAngel

    I was prescribed metformin after giving birth to my baby a couple of years ago. It’s helped with my blood sugar numbers, but I ended up in the hospital with an enlarged liver and lactic acidosis.

    The side effects were and continue to be awful! I have the runs at least 3 times a day…. and it’s difficult to go places because I just don’t know when I’ll have “to go” and how far it will take for me to get to the restroom.

    I want to get off of this medication. I’m taking 850mg twice a day. I can’t wait to see a specialist next week who will hopefully offer me a better med than this stuff. It’s scary!

    • Angelique

      that sounds really high. most people just take 500 a day. are you diabetic or prediabetic?

  • Aine

    Was prescribed as soon as I was diagnosed. After 2 weeks I asked the doctor to take me off it because it made me feel unwell. My trainer said I didn’t seem like I was there. I can’t be any more specific than that. I have been able to control my diabetes fine with diet and no meds. I would not take Metformin again.

    • Jaspen

      When my grandmother would take it, her stomach would start hurting and she would get nauseous. She was taken off of the medicine, and now her sugar is under control. Actually, she had higher blood sugar when she took the medicine than when she didn’t.

  • Peggy Bailey

    My husband has been taking Metformin for about 5 months. No side effects or feeling unwell. In fact his blood sugar is leveling out. Different results for different people.

  • Kathy Lowther

    I have been on Metformin for close to 13 yrs. now! As far as I know there have been no side effects bothering me!

    But I have experienced stomach problems lately that no one knows why! I get frequent leg cramps at night and some during the day! I have a sleeping problem now too! I will talk to my doctor again but probably with no help!

    • Swiftman

      I have been on Metformin for over 20 years. My Type ll is hereditary as I’m not overweight. My readings are 15 – 20% over normal, but continue to be contained. I am very happy with this medicine and do not have any side effects.

  • John Lovejoy

    I was diabetic and didn’t know it, even though I had checkups twice a year. For some reason, my doctor didn’t tell me even though my A1C was 8.9. My doctor left and was replaced by a new doctor, who happened to be on her last day before retiring. She told me I was diabetic and should get on insulin immediately. I couldn’t believe that prescription. Long story short, I met “doctor” #3 shortly afterwards, who put me on Metformin. I had been somewhat overweight but began losing two pounds a month. Ten months of weight loss put me 40 pounds lighter than I had been. And I felt great. I still do and my weight is holding steady. Blood panels and urine tests show that I am fine in that regard. So, to sum up, Metformin for me was a lifesaver. Haven’t felt this good for decades, and I’m 76. And my AIC is 5.8.

    • That’s great news John. I’ve had all 3 of those types of doctors so I totally feel that experience. Do you mind if I ask, are you still taking metformin, or was a short term enough to “reset” your metabolism, as somebody else here also mentioned..?

  • pastoredsmith

    I’ve taken metformin for 18 years, originally prescribed after a heart attack and with “borderline” diabetes type 2 at age 40 to help me lose weight. I was prescribed a double dose of (4) 500 mg tablets per day (2 in the AM and 2 in the PM) for “the foreseeable future.” Then, I was sent to a surgeon after a month of taking this med with pains in my lower abdomen and the symptoms for gall bladder attack. Exrays showed that I had “sludge” in the gallbladder and it was removed. No stones. The stated reason was that “metformin causes gallstones and as a precaution we’re removing your gallbladder.” For 18 years, and with each dose lasting four hours or longer, I have stomach pain….every day that passes. No doctor will consider taking me off it, even when my blood sugars are way down and A1C is under 6.7. I officially hate this medication! I also have a friend who died from complications caused by metformin (liver enzymes got high and he neglected to keep them checked due to a relocation and doctor change)….Did I mention that I hate metformin? Sometimes, I “forget” to take my morning meds so that I don’t have stomach cramps and pain during the AM…..

    • … but doctors work for you, not the other way around. So if you really don’t want to take it, and genuinely believe that it’s doing you harm, then simply don’t take it… just say to them:

      “I really believe this is hurting me. Here is why… blah blah… and I want to try going cold turkey or cutting down first. Will you support me in this choice if complications occur, help me watch for changes good or bad, or if needs be, is there something else I can take that may be less harmful to my particular metabolism? Because one way or another, I strongly feel that I need to come off this, and I’d rather do it with your support, than not.”

      The best doctors are the ones who listen to your side effects and complications, knowing that statistically, they’re going to get a certain percentage of patients every year who react differently to medical study results. And if it means driving to another town every time you get sick, then that’s what I personally choose to do because my doctor is a country doctor who travels to 5 towns around me so if I want him, and nobody else then I have to go to the town, wherever he is that day…. but at the same time, I also understand that transport and declining health can mean that many people are stuck with whichever doctors are closest. … but in any case, best of luck with your decision…

  • Lynnette

    I’ve been taking metformin 7 years now for type2 diabetes and i’ve never really noticed any side effects. Of course I was taking alot of medication through out the day for other issues that probably hid anything that might have come up….lol. I quit taking it 2-3 months ago (drs still aren’t aware) along with most of my other medications. I started losing weight while doing hoslpice care for my brother in June 2016. By the time he passed in September I had lost a good 40+ lbs and I hadn’t really changed much except I was living out of my suitcase and staying at the care center he was in so I went out to eat once a day (usually dinner) and I ate Yogurt and fruit for breakfast, then I snacked throughout the rest of the day and evening on fruit/nuts/chips. I didn’t really cut down on the amount of food I ate, I think it also involved me walking and running the facility halls tracking down nurses and staff to take care of my brother when the job was to much for me. He was 6’5″ and bulky from years of construction and I couldln’t lift him or roll him by myself. Anyway, after I lost another 30-40 lbs I decided I wanted to see if I still had type 2 diabetes, so I started testing and the numbers were always right where they should be, so I quit taking my meds. I still have low numbers and am taking no meds. So maybe just changing how many meals I cooked and ate for the snacking on more natural foods all day long helped. I encourage anyone with Pre-Diabetes or Type 2 to change your eating habits to little or no meat (or meat products), and eat naturally grown foods. You will see a huge difference….I have dropped over 80lbs and toned up and can fit in regular clothes again. It’s amazing what eating better can do for you, I didn’t it because I had no choice, imagine if you did it conciously what would happen 🙂

  • Ramo22

    I have been taking Metformin for the past 10 years and my problem is the stomach complications.sometimes my stomach is bloated or running or irritated, but if i go 2 days without taking it my stomach is fine. I have been telling the sisters at the clinic but they don do anything and I have decided to stop taking it and see what is going to happen.

  • MSSpahr

    I was started on Metformin for an A1C of 6.6. After about two weeks, I lost my appetite. This continued instead of wearing off as it should have done. By the time I returned to my doctor for another checkup, I had lost 10 lb. (I started out at 135) and could not afford to lose more. I had virtually no appetite morning, noon or night. I took myself off the Metformin and have been on no diabetes meds since. After nine months of no meds, my fasting blood sugars are normal, almost always under 100, and my A1C is 5.8. It’s like the Metformin pushed a reset button on my body. I feel great, my numbers are normal and I am not on a diabetic diet, I eat what I want and I have regained my weight. Maybe a short course of Metformin is curative for a handful of folks. I’m glad I took it.

  • Robyn Ward

    I had been on metformin for over 20 years with no effects obvious until late last year I needed a stent in my heart then again in april I needed another stent and also suffered badly with fluid on the lungs causing difficulty with breathing. Two weeks after being released from hospital I was rushed back into into hospital unable to get my breath and was diagnosed with pneumonia for which i was treated with strong antibiotics. After 4 days I was starting to feel a lot better but this was short lived as by the 6th day my breathing got much worse. My doctor in desperation to find the problem ordered a special blood test only to discover it was lactic acidosis from the metformin. Thankfully stopping metformin started showing great improvement immediately. This doctor was not an endocrinologist but a cardiologist and had seen this problem only once before.

  • Janice McNider

    I started Metformin 20 odd years ago, and was taking 6 tablets per day, I was in hospital on and off with urine problems for years until 2016 . This was different I was throwing up no matter what I ate or drank my blood sugar was very low and it just would not go up because of the sickness. I had a very bad Hypo and was admitted to Hospital where they discovered not only was my diabetes all over the place I had lost 3 stone in as many weeks but most of all Metformin along with a handful of other drugs for blood pressure, water retention, and another diabetic drug had damaged my Kidneys. I had a biopsy and both my Kidneys were badly damaged. Now I attend the Renal Clinic approx., every 6-8 weeks, and I have to change my diet to low salt and low potassium . I was diagnosed with diabetes 29 yrs ago at the age of 33yrs but was told It was possible that I had been diabetic for at least 4 years meaning I would be 29yrs old before that.I am now nearly 63. Metformin with a combo of other drugs gave me CKD. What Next? I think your Doctor knows you best and therefor should give you what you need and not what faceless people in big chairs sitting telling Doctors what they should give to everybody regardless. I by the way live in the UK.

  • P Aurora Robinson

    I have been taking Metformin for 10 years now due to a number of medical emergencies that rendered me more immobile than my body should have been, the heart issue won! To add insult to it all I was diagnosed with Crohns Disease a few years earlier and so the battle between weight gain and weight loss rages on. The pre-diabetes diagnosis has me perplexed and the Crohns makes matter even more perplexing. I take 500 mg daily of Metformin, and watch my diet constantly. I can not get rid of the fat around my middle regardless of the exercise I do.

  • Darrel Buccilli

    I have a question, For 3 years now I have been on 1000mg of metformin and lantus insulin injections yet I rarely can get my sugar to go lower then 200, most likely cause I can not exercise very much I have a degenerative bone disease in my spine and have to walk with a cane, plus arthritis in my right knee. Recently my insurance stopped covering lantus is there something stronger than metformin and lantus that will bring my sugar down lower and lower my a1c as well?

  • Kathy A Longino

    I have had 2 or 3 doctors that said metformin causes b12 and D deficiency.

  • DevilDog83

    Metformin almost killed me. I had a severe reaction to it that was disregarded by my “nurse practitioner”. After a couple of weeks I told her my numbers weren’t getting better, but going up. She doubled my dose. She didn’t think my symptoms were serious, but I lost 30 pounds in three weeks without changing my diet, I was sleeping only 1 hour at a time per night, and my blood sugar went from 150 to 480 while on metformin. I fired her. It may help some people, but don’t ignore dangerous side effects if you are taking it. I take Jardiance now with no ill side effects and my A1C is under 7.

  • radiostar

    My blood sugar was at 108 so I was prescribed Metformin. I tried just a quarter of a pill. An hour later I had a bad headache so decided to check my blood pressure; I found that it had gone from 110/65 to 135/85! I haven’t taken it since but I will try again today to see if the same problem happens.

  • DonnaSC

    Nasty stuff. I took it and crawled to the sofa. Two hours later I had built up enough energy to crawl to the bed, then back again. I stay on the low simple carb diet and it works way better. I’ve been “borderline” diabetic for fifteen years now.

  • TwigaBob

    I have the same results for the same dosage, for only 3 years though. No side effects.

  • lani4

    I have been taking 2 – 500mg tablets of Metformin twice a day for 6 years and I have never had any problems with it at all. Dr added 3.75mg of Glyburide a year ago when because of my disabilities I am unable to exercise enough to help control blood sugar and my blood sugar has been even better since then. I am 77yrs with type 2 diabetes.

  • Shelia Barnes

    I have memory problems, so no longer taking…guess what, memory came back!

  • Marco

    Yes, back in March of 2016 I woke up and realized I could not walk. I ask my wife to take me to the hospital but she was too busy and had things already planned for her day. So I made it there on my own and the police almost arrested me once I got there because of my pain and my inability to walk. I had to craw on the blacktop and the police saw me and pick my up and rolled me in. After several hours of being tested they said that my L3, L4l L5 and S1 were all ruptured. They could not believe it. The level of Sciotia was so severe that options were few. Any ways, one of my clients who happens to be a Spinal Specialist told me to start hanging upside down for about five minutes each morning and right before I go to bed. I did and September 2016 I begin walking again. Then after going back in to review my situation that is when I was tested for Type 2 Diabetes. I was around 294 pounds (very over weight) about 6 ft tall and was considered to start having problems with my heart very soon. My doctor immediately put on on Metformin pills and I decided that this is not for me.

    I begin taking inventory of myself that day because this was a true wake up call. I got up the very next day and started a healthy eating plan and balancing act. I had to make some adjustments because I loved junk food. After that I immediately begin working out like with some basic things like setups and walking and jumping and hanging upside down and doing about 10 or 12 pullups upside down and wow you talking about having an affect on your middle core area. My belly was benefiting from this after about two weeks. All my messed up disc were being positioned back in there places which did not happen until a few months later. After two months I did not need the pills any longer because my blood sugar started leveling back to a normal range around 120 to 140.

    After 10 months I noticed my waste line went from a 44 down to a 38. My shirt sizes went from a 2x Large to a Large. My big belly which looked like I was about to give birth went back to a flat belly just like it was when I was in high school. Wow! What a difference it is now. I am now about 210 pounds and waste line is averaging around 36-38. My back and core is much stronger and my blood sugar is no longer a problem. I eat now to live rather than live to eat. There happens to be a big difference here. Was it easy? No it was not. I pray every day for my condition and make better choices and said so long to all the sweet foods, sugars, sugar drinks of all kinds, sweets in general.

    Every now and then I will cheat and have a ice creme or sweet tea. But taking control of myself and asking God to help me make the right decisions has truly paid off for me. Now the Federal Government filed suit against me, my back went completely out, then my wife decided to call it quits with one child about to leave the nest two others already out on their own, four granddaughters and one grandson and experiencing all this within a two year period. But God is good and now I feel better at 58 than I did at 30. My practice is doing well and my past is the past. Just a few words that I felt some one some where could use and help build their faith.

  • Spartacus

    I’m 55 year old who was diagnosed type 2 in the year 2000, doctors kept increasing levels from 1 x metformin 500mg a day then 2 morn/eve, 3 morn/aft/eve finally 4 everyone of these tablets were no use they then prescribe another tablet Avandi first 1 then 2 morn/eve that was Total of 6 tablets each day for months my sugars kept climbing kept telling me they would eventually start working? I told diabetic doctors and nurses I might as well be throwing them down the toilet I stopped taking Advandi as it was making me ill eventually stop eating to lower my sugars (Not recommended) as this made me more ill but quickly lost two stone then they put me on insulin novomix 70/30 wow something started happening but they had to increase dosage in steps finally finding my dosage which was quite high? even though at the time I was active. I then needed hip surgery 2007 from worn hip cartilage from/due to a motor cycle accident (smashed pelvis) when i was 24 years old and became very immobile sugar levels climbed so novamix increased higher. Had surgery a year later had the whole total hip replacement removed due to a close to death infection too long a story to tell basically sister bugs for MRSA instead of eating me from outside in they were eating me from inside out, on/off other surgeries took place for a total 6. Now on/off in between surgeries when i was active i seemed to struggle with sugar levels climbing and experience pain in my good leg and my right arm/shoulder cramps in same leg and cramping pain in hands and fingers, feeling tired and more I tried to exercise the more my sugar levels increased? Which seemed strange ended up with hammer toe now wear hospital shoes due to this. They change my insulin to Humolog 50/50 as my kidneys and eyes were getting affected due to sugar levels increasing ended up having eye laser surgery to clean up leakage to my right eye my kidney function worsening now down to 45% although sugar levels much improved then two years ago. My eyes got better but my kidneys got worse although the more active I got the worse I felt. Cramps when sleeping, waking me up unable to sleep and pain which only got better with inactivity then cramps when driving to the one leg using the pedal as it automatic this stopped me driving and turned to walking more as I put it down to circulation but more pain more cramping more I walked and the slower I got. Old age pensioners were over taking me and they were on walking sticks ended up taking my walking stick out
    Rest help saw doctors about it as I was taking over the counter pain killers for the pain/inflammation ibuprofen worked but no good for kidneys, docs kept changing painkillers up-to co-codamol, as I had to pain now to my lower back, hips, thighs and down lower legs, upper sides of torso. Hips X-rayed no cause of pain could be found so stopped taking pain killers when resting pain never got better this was not normal so had to find the cause of this as I felt it would kill me? Looking at the leaflet for metformin side affects I found that on/off I had most of them but changes to diet kept most at bay all except the one I felt was N.A or was it applicable Lactic Acidosis (medical emergency) now anyone in their right mind would be straight down to A/E if they believed as strongly as I did that this could be the cause no I’m mad although in pain waited till the next morning walked to the doctors (Which is a long walk) and requested an appointment to be seen also requested an asthma inhaler as i’m asthmatic on/off thinking if lactose acidosis interferes with the transportation of oxygen to muscle cells i need all the help i can get, Seen GP next day and another long walk, this was the earliest I could be seen and politely requested to be taking off and given an alternative to metformin tablets that did not have the same medical emergency side effect with my reasoning she did as requested but question why I never went to A/E if i strongly believe this to be the case, I replied i’m in pain as I now refuse to take pain killers I actually have a high tolerance to pain i’m monitoring the pain god will help me as he made me work out what I believe to be the problem, I’m also drinking lots of water to flush out toxins. She changed my med to januvia 50mg one in the morning which I was told to start next morning left the docs all my joints involved in walking feeling the pain and sore, next day same thing pain getting even worse and i now going so slow i had friends now concerned for me as I passed by them I had to get some electrolyte powder from the chemist as i was now feeling totally drained of energy just encase it was not Lactic Acidosis as i lose these with kidney problem. Got home and now in much agony thinking you fool you should be at A/E but feel asleep woke up two hours later pain not as bad inflammation seemed to be calming down with no pain killers that’s good later decided as the pain eased off more thought lets see if I can speed this up then decided to get on my rowing machine see pump this toxins out of me quicker 800 rows later gentle rowing lots of water lots of trips to toilet went to bed next morning woke slept much better pain now at an ache but had this before but agony when i get out of bed but felt so much better, noticed how much easier all my joints were stiffness gone was able to stand whilst putting my trousers on balance which was also off wow had returned this is too good to be true after all that pain i thought am i still dreaming? Or not really woke up yet? Then a little nagging pain here and there no I’m awake. So headed off out after wash etc… collapsible walking stick in hand in case pain returns things look good no pain lets try going a bit faster this is fantastic by the time i got to the village yes a long walk met three friends along the way who saw me in total agony the day before were amazed how i was not only without walking stick but had now got my speed back after months and months of problems they never seen me looking so happy. Moral of this true story if your on metforin and seem to work if you not too active then if your happy keep taking them and if your trying to get fit and your in pain with cramps feeling tired sugars climbing or hard to control then be warned you could be poisoning your kidneys and body by staying on it.

  • I was diagnosed with Type II diabetes in 2005. My VA Primary Care put me on 500mg x 2 of Metformin and 2.5mg of Glyburide daily. Five years later the Metformin was increased to 1000mg x 2 daily. The Glyburide went from 2.5mg once daily to 1.5mg x 2 then to 2.5mg x 2 and then 5mg x 2 daily. To make this a bit shorter I have been on 1000mg x 2 of Metformin and 10mg x 2 of Glyburide daily for over 7 years now.

    Two and a half years ago my Primary Care’s RN convinced to stop refusing to go on NPH Insulin. I should have done it years before when the Doctor first wanted to put me on it. My A1C numbers were out of control even when I tried my best to watch my food intake.

    In addition to the 1000mg x 2 of Metformin and 10mg x 2 of Glyburide daily I am now taking 16 units x 2 of NPH Insulin daily. My A1C numbers finally keep my Doc from rolling his eyes up into his head. I’ve been recording A1C’s in the mid 7’s and it looks like I might be on track to be in the low 7’s.

    On each visit he asks if I am having any side effects from the Metformin and knock on wood I have not had any. All of my blood work comes back with good numbers across the board except for lower Vitamin D numbers.