metformin neuropathy

Can Metformin cause Neuropathy?

Remember your last annual foot check? They poke and prod your feet to check your sensation is normal. They ask you questions about your shoes and whether cuts and blisters heal properly.

You’re hoping that they tell you everything is normal, right? The biggest worry of nearly every diabetic I talk to is amputation.  It can’t even be called a phobia, a phobia is an irrational fear. It’s totally rational to be terrified of amputation if you are a type 2 diabetic. Amputations happen to 135 people a week in the UK, add a zero onto that number for the States.

A diabetic is 25 times more likely to lose a foot than the general population and 70% of all amputations worldwide are in diabetics.

Nerve damage is where it all starts, that’s the reason why you go for an annual foot check. The doctor is trying to pick up the early signs to protect you. High sugars are known to cause nerve damage. But what if the most commonly prescribed medication for diabetics could be adding to the problem?


Metformin and B12

If you have type 2 diabetes you are more likely to be deficient in specific hormones and vitamins, like testosterone and vitamin D – that’s a topic for another time though.

Metformin causes B12 deficiency in 30% of users. Metformin acts in your digestive tract and can reduce the absorption of B12 from the food you eat.

Guess what B12 deficiency causes? Neuropathy! Yes, B12 deficiency on it’s own causes nerve damage. If you have diabetic neuropathy and B12 deficiency that is definitely going to accelerate the damage.

The risk increases with a higher dose and the length of time you’ve been taking metformin for.

In his article published in Medscape, Dr Bell states:

“However, a common, potentially damaging, and well-documented complication of metformin—vitamin B12 malabsorption—is poorly recognized and not screened for or treated prophylactically by the majority of physicians who prescribe metformin. This is unfortunate since a correctable cause of irreversible damage to the central and peripheral nervous system may be overlooked. “


If you are diabetic this really is a key vitamin that you do not want to be deficient in.


How to make sure you are getting enough B12


  • Getting your blood sugars in the healthy range ( below 7.8 mmol or 140 mg/dl ) can help increase absorption of B12 from your diet
  • Best B12 foods are meat, eggs, dairy products, seafood.
  • B12 doesn’t occur naturally in plants – if you are a vegetarian you may wish to supplement
  • Sleep and exercise are also important.


What to do now

If you have signs of neuropathy or are concerned go to your GP and ask for a blood test to check your B12 levels, the results will let you know what support your body needs.

The test for B12 levels is simple and can be done at the same time as your HbA1c without any hassle.

It used to be thought that you couldn’t take too much of the B vitamins – we now know that B3 and B6 can cause issues at high levels. With B12 researchers have found no evidence of side effects at all. Here is the supplement I recommend.

There is plenty that you can do to prevent ever being a statistic.


Has your GP ever tested your B12 levels?



  • Christina

    Reply Reply February 15, 2016

    Already have nerve damage about 2 years now and on that dreaded medication for over 4 years.I have now been told I have a a infection in my legs which the doctor has told me it is cellulitis,the thought of amputation frightens me to death I think I would rather die.I have been waiting 2 weeks for a blood test,and have given up all hope.

    • Mary Kemp

      Reply Reply February 15, 2016

      Hi Christina, I’m so sorry you’re having such a scary time of it. There is still lots you can do. Important to keep pestering your doctor for intensive treatment of the cellulitis to start with. How are your sugars at the moment? Anything you can do to drop them will make a difference and help your leg heal. It is not too late at all. You can email me direct

  • Stephen

    Reply Reply February 16, 2016

    I have B12 injections every 12 weeks I have been on Metformin for 12 years and have no signs of Neuropathy.

    • Mary Kemp

      Reply Reply February 22, 2016

      Hi Stephen, that’s perfect. The Vitamin B12 will be helping your nerves and keeping blood sugars low helps massively too.

  • Gloria Brockmiller

    Reply Reply June 28, 2017

    I have been type II diabetic for over 22 years and been on metformin since it came out. I have such severe neuropathy that I am going in for an apt to see if I am a candidate for spinal cord stimulation it is surgery for the spine. Not excited to have it . I have tried many pills and acupuncture and dry needling massage PT and pain patch and essential oils and was on lyrica and got in car accident. Metformin gave me the neuropathy not the diabeties !!!!! Gloria

    • Gareth Kemp

      Reply Reply August 30, 2017

      Hi Gloria, you are right – metformin can definitely have side effects and vitamin B12 deficiency can cause terrible symptoms like you are experiencing. I’m so sorry you are having to go through this and I hope the spinal stimulation helps (if you are a candidate).

  • Mary Lou Bevins

    Reply Reply May 15, 2018

    Was on Metformin when 1st diagnosed then it really bothered my stomach. So been off it for awhile. Just went from just B12 to a B vit. Complex. Should I go back to just B12?? Taking A.L.A hoping that will take place of my neuropathy med. Should it?

    • Mary Kemp

      Reply Reply May 23, 2018

      ALA will help and Vit D3 helps nerves repair and reduces pain if you already have neuropathy. The B vit complex is fine 🙂

  • Tom Roncarelli

    Reply Reply May 16, 2018

    Thankfully I have not yet suffered any nerve damage (as far as I can can tell). I do sometimes sprinkle Marigold Yeast Flakes with Vitamin B12 on top of salads, soups etc…it has a cheesy sort of flavour.

Leave A Response

* Denotes Required Field