Metformin at 4 tabs a day made me low-grade nauseous all the time, and I would occasionally wake up during the night to vomit. Lovely! It also caused loss of appetite (not in a good way) and I suffered the more traditional unfortunate bowel effects off and on. For 3 months.
But I did as
@bulkbiker suggests and went keto from the word go, so after 3 months my BG had normalised and I was able to cut the dose by half which fortunately did not affect me the same way. After 9 months I stopped taking metformin all together, no need for it. I could probably have ditched it completely after the 3 months but I was just cautious, especially since a lower dose was much more tolerable for me.