I have been on and off it for 5 years or more.
I first went on when I was about 16 or so to help with cramping and to see if it improved my complexion.
Then I went off it and back on probably when I was about 18 or 19.
I don't think I have had any side effects. As for weight gain, yes, I have gained some weight since then, but I think it just has to do with the 5 years since i've been on it not becuase of the pill.