Trying out Metformin... Wow!

2 posts were merged into an existing topic: What is your experience with SGLT2 inhibitors?

So one thing I can say about the split in metformin is that, while it is AMAZING during the non-hormonal weeks, it does absolutely nothing for hormones. Even with upping my basal dose by 50% I still had significantly more highs (and much higher and more protracted highs) over the latter two weeks of my cycle. As soon as things “reset” it goes back to being utterly amazing. I really feel the impact of hormones on my blood sugar is the reason I can never get an A1c below 6%. My estimated A1c in Dexcom is back up to 6.6%. And that’s not bad… It just drives me crazy having to struggle so much with highs and variability half the time when the other half I’m able to do so fantastically.


I’m sorry that it’s no help during part of your cycle. But I am heartened to read you found something that helps during the other part and gives you better control. I’m curious if you stopped taking it all together during the two useless weeks if it would be even worse?

Thanks for sharing about this. I’m guessing it’s going to help someone who’s in need of the knowledge!

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At least you have 2 awesome weeks out of the month :slight_smile: Hopefully that offsets the other less than awesome weeks.

After my recent trip, I’ve decided to switch back to Lantus at my next appointment. My basal needs fluctuated drastically throughout the trip. First, I was running low from all the exercise (average of 22,000 steps/day according to iphone… which I know isn’t accurate, but still…), and then my liver caught up and started dumping all the fantastic carbs I’d introduced (pasta, pizza, croissants, oh my!!!) so I had to raise my basal higher than it’s been in awhile - yet I still ran high any time I sat down for more than an hour, making the plan ride home challenging. Overall, I transitioned down 3 units then up 5… all within the space of 2 weeks. That’s a lot of movement for me!!!

I’m sure that when I switch back I’ll have complaints about Lantus, but I think I’d like to deal with those for awhile instead of the complaints I have with Tresiba. It takes days for my body to catch up to a dose change, and I’m constantly adjusting around my insulin. I honestly started thinking about going on the pump the other day… which I never thought I’d say again.

I can’t run late with Tresiba like I’ve heard other people do because I notice it 12-24 hours later (though a 2 hour delay isn’t a huge deal). I don’t notice the impact of dose changes until at least 12-24 hours later either. So I feel totally trapped into the dose I gave 1-2 days before.

Maybe I’ll change back to Tresiba one day, but I need a break. I remember how much I loved Tresiba when I first tried it, so I find it really interesting/strange that my feelings have changed so much. Maybe I’ll switch back to Lantus and remember all the reasons I loved Tresiba :smile:


I had similar problems with Tresiba… I started out running super high and put my dose up to 40 units… Then started going low so lowered it to 20 units, and things seemed OK there for a few days, then I shot up super, super high again… Knowing that my basal needs fluctuate by about 50% every two weeks, I think that was a big part of my problem. If I ever want back to MDI I would definitely use Levemir, because I don’t think anything else would be able to keep up with my basal fluctuations.

When I miss a single dose of metformin I run quite high for the day. So I’m sure metformin lowers my overall insulin needs. I think taking it half the time and not hte other half would mess up either half. However, it might be interesting to only take it during the difficult two weeks and not the easy two weeks. Maybe then my insulin dose would fluctuate less.

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It’s been a few months since I started Metformin now.

Overall Results:

I would say that overall I’m averaging 108-112 mg/dl. This is about a 5-10 mg/dl drop in my averages from the 3 months prior.

My 90 day average gets a little messed up by a really rough week in the end of February when I was in Italy. My basal needs jumped by 5-6 units and my average bumped up to 122 mg/dl. I think two weeks of pasta and pizza caught up with me :smile:

I think my standard deviation is the more impressive statistic. It’s dropped about 5 mg/dl. I’m consistently running a standard deviation of 26-31 mg/dl for each 2 week period. The total standard deviation over the last 90 days is 34 (largely due to that week the end of February).

Ongoing challenges/observations:

Contrary to my expectation, my basal needs fluctuate a bit more while on metformin. I’m still working on understanding the variables involved.

Before starting Metformin, I had a 1-2 unit basal need variation depending on the time of the month and activity levels.

Now, I’ll go through times where my basal needs are at 20-21 units/day for a 1-1.5 week-long period, then it’ll jump up to 24 units/day. 24 is still 1 unit lower than my lowest basal needs were prior to starting Metformin, but that’s a HUGE jump from 21 units.

I don’t think it’s entirely attributable to my activity levels (though I suspect they play some role). It may be due to carb intake, but I’m not really sure. I suspect that it’s due to hormones, but the patterns are very different than hormone patterns I’ve previously had. In addition, my prior hormone patterns don’t seem to be occurring - I’m not sure if it’s because they’re obscured by whatever this other variable is or if my basal needs due to hormone levels have changed… if that makes any sense.

Anyway, I’m going to start recording when my basal need changes occur so I can hopefully determine the causes and see how they relate, if at all, to my monthly cycle. If they do relate, I promise to post it on the hormones thread @T1Allison :slight_smile:

I still have some nights where I run a little higher, but I respond to my insulin and understand the causes when this occurs. Overall, my evening spikes, when they occur, peak at much lower values because I can control them. It’s still my most challenging time of the day, but I feel like I can control it much more easily.


Looks great!

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That is breathtaking, @Katers87. Super happy for you!!

That’s right! Accountability City here for the cause of the sisterhood!! :grin:

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When I was (miss)diagnosed as type 2, I was taking invokana and metformin 1,000mg twitce a day. then DKA occured… hospital, switched doctor, diagnosed as t1 and then he (the doctor) took me off both pills and put me on insulin.

He told me that there was a time in which metformin was banned because of some issues with patients dying (didnt even know… havent researched that myself yet).
I have read that invokana is known to have some nasty side effects.

So anyway… I’ve been tempted to take metformin to see how I react in conjunction with insulin… but Im a little scared to do the experiment.

Dr also told me that if I ever switch to another doctor I should say to him/her not to give me metformin… I guess I should follow the indication.

Congratulations on better control with less insulin.

I’ve also felt like metformin has perhaps sort of “emphasized” my hormonal changes. But I can’t put my finger on how. A bit ironic, as I originally started it because I was interested in seeing if it helped with my hormonal fluctuations.

I would try to stop and see what the change was, but every time I miss even one dose my blood sugar skyrockets to crazy high levels. So it’s clearly doing something, and I already have a pretty hefty insulin dose even with metformin, so I don’t really want to stop if it means I’ll have to take a hundred units each day. My endocrinologist says not to stop taking it if it’s helping my blood sugar. (Again, ironic as he originally didn’t think it would make any difference!)


I haven’t read anything like this. On the contrary, nearly every study that includes Metformin lauds at least one of it’s attributes. I’ve only read one or two negative studies that contradicted all the other studies (which is seemingly par for the course with any studies) - none of which included the drug killing patients. Metformin is not recommended for people with significantly impaired kidney function (along with a lot of other drugs). Otherwise, there are only a few cautions (such as not drinking heavily).

Metformin has helped me significantly, so I want to be very clear to anyone reading this that the statement your doctor made is INCORRECT. If you have a study or even a news article to provide to back-up that statement, then I’m happy to discuss that. But a comment like that (even without anything to back it up) can scare people from using a medication that might actually help them quite a bit. Sorry if I’m coming off a bit harshly.

Metformin is the most commonly prescribed drug to treat type 2 diabetes. It’s incredibly different than Invokana which is an SGLT-2 inhibitor.

I would not be willing to take Invokana unless I had severe insulin resistance and could not control my bg levels any other way. I’ve read many reports that link this drug with foot amputations and kidney problems. If you search it on fda. gov , you’ll see all the many warnings.


It’s too bad they didn’t catch it sooner! I’m sorry you had to go through that.

Metformin isn’t intended to replace insulin in people with T1. It can just help with insulin sensitivity. As a T1 without any functioning beta cells (as far as I can tell), I’ll always need insulin.


So this is what happens to me when I forget a dose of metformin. Today was one of those days where I could NOT figure out why the heck I was running SO ridiculously high for most of the day. It finally came down when I came home from work (a time I typically go low). Then as I went to take my evening medications, I saw that I hadn’t taken my morning medications, which includes a dose of metformin.

I don’t remember noticing a huge, dramatic shift in my insulin doses when I first started taking metformin about two years ago. But clearly, over the past couple of years I’ve adapted my insulin doses to it, or else it’s begun having a greater effect on me, because this type of disaster happens every time I forget a dose.


I had my endo appointment today, and it was probably the most helpful appointment I’ve had so far with this doctor. I’ve been seeing him for 1.5 years, and I think the longevity is helping a bit with our interactions.

He suggested I switch to Lantus for trips after I discussed my problems with Tresiba and travelling.

I’ve also gained a couple more pounds. It may just be water-weight, but I thought I was losing so I still find it concerning. He asked a lot about hypoglycemia, and he proposed that I might be struggling with weight due to the inflexibility of Tresiba. I told him about how exercise and my monthly cycle can result in my combating lows while I wait for my Tresiba dose change to catch up. Combatting lows means eating more than I would normally. These lows are hardly visible on my clarity reports because I usually head them off before they occur or address them quickly at night.

When I suggested a full transition to Lantus he was very open to it. I think it was helpful for me to pose all the problems and lead him to the solution I wanted :wink: He’d come to the same conclusion by the time I was done describing everything.

Carbing up a bit after a workout can make a huge difference in how much extra I need to eat over the next day or two. I’ve been trying to make it more of a priority to have carbs right after a workout. It can mean the difference between waking up 3-4 times during the night and eating tons of carbs (100+ total on an occasion when I forgot to carb up at all) to avoid a low or just having 30 after a workout. I think Eric wrote about how liver and muscle glycogen can get used during heavy workouts, and the carbs you eat immediately after a workout are more effective at replenishing your stores (instead of eating tons of carbs later on and slowly replenishing stores). I’m not going to pretend to completely understand all of the factors there, and I’m sure he said it better somewhere else (so search for it!).

Anyway, all that is to say that the effect seems even more pronounced while on Metformin, and it may be because I usually take Metformin in the evening around 2 hours after my workout. So carbing up immediately after my workout and before my Metformin dose seems to work best at allowing me to maintain the same basal dose (which is the goal with Tresiba). It’s not perfect of course, and all of this seems to be much more challenging in 2 weeks of my cycle (the week before my period and during most of my period). The two weeks immediately after my period often seem dreamy in comparison.

I’m hoping that with Lantus I won’t need to carb up quite as much because I can easily reduce my dose on the days I work out. My doctor seemed to think switching to Lantus would really help stabilize my weight, and I think that makes sense. We’ll see if it actually has any impact though.

Anyway, my monthly cycle basal needs seem to be pretty much the same now @T1Allison. I’m pretty sure the basal need changes I mentioned earlier were entirely related to exercise. It’s just that the effects after exercise lasted longer if I didn’t carb up properly, so it obscured the problem. I hypothesize that replenishing the glycogen stores on metformin is more challenging, so the effects last longer (just a theory… I don’t know if that’s true). So any variation in exercise can create the appearance of a more dramatic variation in basal needs. If that makes sense?

I’m excited to start Lantus again. I’m really looking forward to being able to change my dose easily. Sorry for all the rambling! I’ll be impressed if anyone actually reads all that :smile:


I only started metformin on top of my insulin 4 days ago and the results are unbelievable. Honestly, I don’t really believe it.

Here is my nightscout average for the last 3 months. 6.1% A1c estimate. I thought I was doing great.

Here is it for the last 3 days. Not a single spike. No change to insulin amounts (that I can tell). I even had pizza!



Man that is tempting me to crack open my bottle.

Are you taking standard met or the extended release? And once or twice / day?

That is really amazing results. Thanks for posting. I look forward to more of your informative posts. Wow!

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500mg XR once a day after lunch. My endo suggested upping the dose by 500 every week or two until I hit 2g (subject to side effects such as diarrhoea etc) - but I’ll see how it goes with just the 500.


Do you have any residual insulin production? The LADA label on your profile would suggest that might be the case. If so, I’m thinking that the metformin would help a lot to amplify the effect of the residual insulin as much as possible.

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