How much weight will i have to lose to regulate my cycle with pcos ? i'm 5'6 165 lbs .

No exact: An ideal weight is about 136 lbs for you but there is no exact amount that will flip a switch. Any weight loss will start to give metabolic benefits. Good luck.

No way to tell: There is no exact answer, but every pound will help. Talk to your doctor about metformin which may not only help weight loss but reduce Insulin resistance, and can restore normal menses and fertility in many women.