Metformin and type 1?

Hey guys. Have any of you type 1 diabetics found benefits through the use of metformin? I’m have seen benifits in studies but wanted some real life feedback. Thanks!

Wecome to TUD, Tim! And yes, I’ve been taking it for years. Started back when I was on MDI as a way of ameliorating dawn phenomenon. Switching to a pump did a lot more to help with that but I’ve kept taking it because it helps keep sugars down and has other benefits.

My endo refused to prescribe it stating that there were no studies proving its effectiveness in type 1 diabetics. A simple search on pub Med I was able to find a hand full of studies that showed many benefits for type 1’s. She must just be stuck in her ways and not willing to think outside the box…

1 Like

Welcome to TuDiabetes, @Tim_Estergaard. It always frustrates me when doctors refuse treatments based on rigid following of their understanding of the standards of care.

Here’s some text from the 2019 American Diabetes Association Standards of Care (SOC).

The addition of metformin to adults with type 1 diabetes caused small reductions in body weight and lipid levels but did not improve A1C (31,32).

The SOC goes on to conclude:

The risks and benefits of adjunctive agents beyond pramlintide in type 1 diabetes continue to be evaluated through the regulatory process; however, at this time, these adjunctive agents are not approved in the context of type 1 diabetes (37).

Metformin has a long history and is considered a safe drug with few risks. There is a spectrum of anecdotal experience with this drug and I don’t understand the reluctance of your doctor to let you try it.

A doctor in the US is legally allowed to prescribe any medication for any condition. This is called “off-label” prescribing. There is some risk of legal or ethical challenges when a doctor does this. I consider a doctor’s willingness to prescribe off-label as a mark of personal confidence and a measure of his/her dedication to helping the patient.

I tried Metformin once and couldn’t get past the gastric distress it caused me.

I’m more interested in the insulin sensitizing factor. All studies showed a reduction in total basal and bolus insulin. The less insulin I use the less resistance I will have. I also had a heart attack 3 years ago and am pleased with the cardio protective benefits as well.

Hey Tim!

I am an insulin dependent T2 with a malfunctioning pancreas not producing any measurable amount of insulin. Because I have insulin resistance, when I was taking Metformin (until about six months ago,) it reduced the amount of insulin needed to keep me in normal range.

I have also read that T1s can also become insulin resistant. Accordingly, you should be allowed to test it to see if it helps.

I have gained about 20 lbs since I stopped using it. I have some left over so I am going to start “using” again.


I am a type1 and I use Metformin 3x a day 850 mg.
I can distinctly tell the difference in blood sugar levels when I take insulin with metformin and when I do not , The sensitivity that metformin causes my body to accept insulin is great. Without metformin, I believe I would need double the amount of insulin. Been on it for many years. No side effects with stomach of note, And it very reasonable.

I was not successful with Metformin ER as the total dosage was lower and the dosing schedule I had did not work for me

1 Like

Hi @Tim_Estergaard!

I’ve had type 1 for over 20 years, and I started taking Metformin ER a few months ago. I was hoping it would help with evening spikes. I use Tresiba as my basal, and it seems that I need more in the evening than the rest of the day (Tresiba isnt easily adjustable).

I started at the lowest dose 500 mg/day in the morning. I started in the morning because that’s what the prescription said. After doing some research, I found out that, while ER Metformin works for 24 hours, it is most active in the first 9 hours.


I switched my dose to the evening, and everything clicked into place. My basal needs have dropped several units, and I’m able to more easily avoid the spikes I had before.


Awesome. My doc insisted I should take it in the evening, even when taking two pills… take both in evening instead of splitting… and I hadn’t yet been able to get an explanation why (I don’t struggle with high nighttime levels or dp)

So you took 850mg at meal times with your bolus insulin? I was wondering about the nest timing for metformin.

Good to hear thank you for the feedback

I’m going to switch back to Lantus anyway though. Metformin solves the evening spike problem, but I want to be able to change my dose more easily when my activity levels and carb intake changes.

I’ll probably stay on Metformin when I switch back to Lantus. I highly recommend it. It’s helped tremendously with my overall insulin sensitivity.

I hope it works well for you too.


I’ve had the pills for a few weeks. Haven’t taken any yet. Any initial advice or ideas or just go for it ?

Welcome Tim! Metformin seems to be one of the safest drugs out there for sugar control and I was given the option of going back on it if I wanted to by my endo. I had already been diagnosed as a type 1 and she herself was a type 1 so very up to date and very avid about learning about anything that helps because her mother and her are both type 1’s.

It can cause stomach distress in people of varying degrees. Usually it’s having to run to the bathroom faster than usual. In my case it caused constipation, nausea and vomiting after I had been taking it 6 months and they tried to increase the dose. It didn’t work to just drop back down the dose, I still got sick from it. At the time they thought I was type 2 getting worse. It definitely helped I just could not deal with the side effects it gave me.

Yes, I take 850mg at the time I inject bolus for meals. A 1/2 hour before or after occasionally may happen. If I do not pair up the injection with metformin then the sensitivity effect is greatly lost. But keep in mind that you are pairing up 2 blood sugar lowering items at the same time so monitor your blood sugar. This may or may not be good for you. I do have a bit of soft fatty tissues around my injection area of choice.
I think the metformin helps with navigating the insulin through the fat tissue. I do not know if this is true or not Discuss all factors and concerns with your diabetes team.

Good luck!

If you were prescribed 1000 mg/day, I’d start with one of the following:

  1. 500 mg/day at the time of day you need it most then upping to 1000 after a couple weeks. By increasing the dose slowly, you might be able to minimize the digestive side effects.
  2. If your basal needs are more level, then you could start with 500 mg/morning and a 500 mg/evening dose. It might still be helpful to start with only the morning or evening dose and then add the other (morning/evening) after 2 weeks.

I think easing into something is always better. The action profile is different if you take it with food (see the graph in my first post), and I would recommend doing that. I think I also read that the digestive side effects are less likely to occur if you’re taking it with food.

You might also find 500 to be sufficient for you. No need to bump up the dose to 1000 if you don’t need it.


I just started Metformin ER today. I’m a type I with insulin resistance and a lot of weight to lose. Hoping that Metformin will reduce my insulin needs and assist with my weight loss efforts. I was prescribed 500mg, 2x per day. I’m going to just take it once per day until I see how the GI side effects go for me.

Edit…somehow this next part got lost during my original post. For those of you on Metformin, do you remember how long it took, when you first started taking it, before you started seeing your insulin needs decrease? Thanks!

1 Like

@Jen can you offer any insight to @Edamame.Bean’s question…

For those of you on Metformin, do you remember how long it took, when you first started taking it, before you started seeing your insulin needs decrease? Thanks!

1 Like

Metformin has been shown to have a variety of benefits beyond insulin sensitivity. I’ve been on metformin for 20 years. I am just insulin resistant and it has helped to hold T2 at bay for many years. My DD is a T1 and I often wonder how much it would benefit her as well.

Agreed, completely. I think option 1 is the best, and it’s the way I did it. You then have the option beyond that of going to 750mg or 1000mg at either or both doses if you want to max it out, but always better to ease into something.

1 Like