How much?

Al

So the doctor has me taking 500mg of metformin in the morning before breakfast.. now I’m finding that after my meals, instead of being in the 100-140 range I’m hitting low like after lunch today I was at an 82! Granted I didn’t eat much, but enough that I should have gotten a higher number than that! Does that seem like a lot of metformin? Obviously I have no idea what a “normal” amount is but 500mg seems like a whole lot