So, did metformin or diet lower my A1C? Short answer: Both helped, but the math points clearly to diet and weight loss doing most of the work. Metformin typically lowers A1C by roughly 1 to 1.5 percentage points on its own, per published clinical data.

My A1C fell 6.7 points from 12.5% to 5.8%, and no medication caused my 100+ pound weight loss. I do take metformin, but it can’t account for most of my results.

What metformin typically does

Metformin is a well-studied diabetes medication, and the research generally credits it with lowering A1C by about 1 to 1.5 percentage points. That’s meaningful, but it’s a fraction of my total drop. If metformin had been the whole story, I’d expect to have landed somewhere around 11%, not 5.8%.

The math on my numbers

• Total drop: 12.5% → 5.8% = 6.7 percentage points
• What metformin typically explains: ~1 to 1.5 points
• The remaining ~5+ points: the diet, the carb reduction, and 100+ pounds of weight loss

I can’t assign these with lab precision; nobody can split them perfectly, but the gap between what metformin does on its own and what actually happened is too large to attribute to the pill. → How I got my A1C from 12.5 to 5.8

The part medication definitely didn’t do

No medication dropped my weight. I went from a peak of 356 pounds (before my diagnosis) to 225, 131 pounds, and that came from how I ate and how I moved, full stop. Weight loss and the carb reduction that drove it are, in my reading of my own data, the engine here. → How I lost 131 pounds

Why I’m careful about this

I’m not anti-medication, and I’m not telling anyone the metformin “didn’t matter.” It’s part of the full picture. But the reason this question matters to me is that I’m working toward full remission; which by definition means holding a normal A1C without glucose-lowering medication. To know if that’s possible, I have to be clear-eyed about how much of my result is the diet versus the drug. → [link: Can you get off metformin?]

FAQ

Does metformin or diet lower A1C more? Metformin typically lowers A1C ~1 to 1.5 points; my total drop was 6.7 points and included 131 lbs of weight loss, so diet and weight loss did most of it in my case.

How much does metformin lower A1C? Published data generally cites about 1 to 1.5 percentage points. Ask your doctor about your situation.

Can diet alone lower A1C? Diet and weight loss did the bulk of mine, alongside metformin. For me, yes. What it does for you, I can’t say.