birth control
"As a 33 year old, well conditioned athlete, I had missed periods for over 6 months.  My body fat percentage is extremely low and probably the cause of amenorrhea.  I am on the last "active" pill now of Generess Fe and have changed no other factors in my life since starting this medication (Paleo diet, Crossfit & running).  I have gained 15 pounds in the last 23 days and have never felt more uncomfortable in my own skin. I have taken birth control in the past and never had such an awful experience with side effects."