Etonogestrel
"I got this inserted on December 8th 2011, switched from Mononessa (the pill). On the 10th started a weird brown discharge until the 14th when it switched to a regular period which wasn't heavy at all. That period lasted until the 20th, and then I had the discharge for another 2 days. Ever since I haven't had cramping, mood changes, weight gain, acne..anything, and it's been a month from insertion. I could be jinxing it but so far its amazing. I even got my sex drive back.  

When I got this I was wondering if weight had anything to do with how well it worked for your body. I'm 5'6, and 105 pounds. Maybe the Implanon is more potent in my body since I'm smaller."