Why are doctors still prescribing Metformin IR if apparently ER has way fewer side effects?

Hi everyone,

I have PCOS and I’m using metformin for the second time in my life. The first time was over 10 years ago, and it helped me a lot—but honestly, my strongest memories are running to the toilet with diarrhea.

I was super nervous about starting metformin again, so I’ve been reading tons of discussions here on Reddit about GI side effects. Almost everyone seems to say: “Take the extended-release version, it’s way easier on your stomach.”

But my doctor prescribed me the IR (immediate release) version. Now I can’t stop thinking about why she chose that, and why some doctors still prescribe IR if ER seems to have fewer side effects.

Does anyone know what the biggest differences between IR and ER are, and why a doctor might prefer IR over ER?

Thanks in advance!