If some pill is not needed, why take it?
Metformin is not proved (by scientific papers) to be usefull for type 1 (read: lower A1C), but someone's experiece is good and some other's bad about it.
BUT if you don't have IR, I think you shouldn't take it.
For sure if you don't take metformin some days your BG are highers, but that's because without it all parameters change: basal sensitivity and I/C ratio.
Try not to take it for a month, re-check your insulin parameters and see. If you need only some more insulin but your BG control is good, spare a med and go without metformin.
I'm T1 with insulin resistance and I started taking metformin about a month ago. Prior to that, my TDD was steadily going up and so was my weight. It was so frustrating to have to take more and more insulin to cover a pretty meager, low-carb diet, while exercising and doing everything I could think of to manage D.
Metformin has allowed me to reduce my TDD a bit and I've lost a few pounds. The weight loss is negligible, but it's a relief to see a stronger relationship between my carb intake, exercise, and insulin needs. Luckily, I haven't experienced any side effects. Good luck with it if you decide to try it!
I just have to add this and it´s not meant to scare you but Metformin is hard on the kidneys not only your stomach.
I started Metformin after two islet cell transplants. I got off the pump but my blood sugar was a bit too high in the morning and my own insulin production was not enough so the doctors put me on Metformin. Side effects from post transplant medications was heavy for me and when my kidneys started too fail the first thing they took me off to relieve my kidneys was Metformin. Today my kidneys are fine after quitting all meds and going back to being a type 1-diabetic. Kidneys was starting to fail only because of the meds I had to use after the transplant including Metformin.
This argumeant is off the wall.
Metformin helps arrest excess Liver Glucose release and phantom liver dumps.
Type 1 and type 2 arguments are off the wall and simply dogmatic arguments.
If Liver is working fine and handling buffering dumps correctly and insulin resistance is low; there may be no need to take.
On the other hand;it is a tool with certain capabilities.