I can’t comment on insulin or type 1 diabetes, but when initially diagnosed type 2, 7 years ago I was started on Metformin. I was prescribed one 500mg tablet week one, two tablets week 2 then up to three tablets week 3. I took that dose for 6 years and apart from a bit of gastric upset for the first ten days or so I tolerated it well. It did suppress my appetite a little and I did lose a shed load of weight. However I really think my weight loss was mainly due to dietary changes. Long story short this time last year after a few difficult years I had put some weight back on. So I swapped to a GLP1 med which has enabled me to lose that weight. If the Metformin doesn’t work for you it might be worth asking about GLP1s, although I don’t know if they are suitable for type 1s.