Etonogestrel
"I have had my Implanon in since February 2011, so 14 months. It has been really great. At first I was gaining weight, but that was because of unhealthy habits. Now that I am up and moving more, drinking less soda and more water, I am losing faster than ever. I get a "period" every 3-4 months or so, and even then it is just 3 days of slight spotting. The only negatives I can think of are slightly decreased sex drive (which you can work through) and sometimes feeling a bit depressed (which usually lasts less than a day). If you are thinking about getting Implanon and are turned off by the possible side effects, just try it. It can be taken out any time. And remember, there is no "natural" birth control, everything has side effects."