Metformin Doses

[JK90]

Hi Everyone
I'm new to the forum but not new to this condition. For the last 10+ years I have been taking Metformin which has never improved my condition at all. I was taking a dose of 1000mg daily but my fertility nurse has recommended I up the dose to 2000mg (1 x 1000mg twice a day).
I was wondering what doses other people take as I think this is a pretty high dose due to the fact that I have never seen improvements for the last 10+ years. Also I was quite interested on reading through other topics about an insulin resistance blood test, which I have never had either and I'm wondering if I should ask for this test?
Thank you
xxx