If you're a T1D taking Metformin when do you take it? Changing dose timing had a huge impact for me

I’m a T1d that’s been on Metformin (500mg, 2x/day) for a long time. I had always taken it when I wake up and with dinner. But until recently I often had an inexplicable spike in blood sugar between 3 and 6AM. Sometimes nothing, other times as much as 100 mg/dL. It was maddening because I couldn’t figure out what was causing it- it seemed completely random as far as I could tell. I mentioned this to my PCP at my last physical and he commented that I should try taking my Metformin dose at bedtime (~11PM) instead of with dinner (5-7PM). Oh. My. God. That was it. I haven’t had my 3AM spike since making the change, and the one or two nights I forgot to take the Metformin had bad 3AM spikes. My best guess is that the bigger spikes occurred when I had an earlier dinner (and Metformin) and I never made the connection. So if you have a similar early morning blood sugar spike you might want to consider trying Metformin at bed time.


Is that with metformin XR or regular?

1 Like

Just regular.

1 Like

@bwschulz Type 2 on a pump and on Metformin here, it’s early to tell, but I have moved my evening dose to close to bedtime. That one change seems to have decreased both dawn phenomenon and Feet on the Floor syndrome.

I hope it continues to work over time. One thing I’ve learned overt the past 32 years that managing blood glucose levels is a dynamic thing. What works today might work tomorrow or not. And my heart goes out to women who have their cycles causing BG issues, maybe up, maybe down.