"i went on yaz about 2 to 3 years ago to cure acne and very heavy periods. it worked brilliantly for both but it has caused extreme weight gain for me. i gained 10kg (around 20lbs) in the first few months and now i am considered overweight on the bmi for the first time in my life. i have tried everything from gym to cutting out carbs and can&#039;t lose any weight. i put this down to being a estrogen dominant pill. i just had my period and do not plan to go back on it."