Hallow Dear, Implanon is a birth control devise which contains Progesterone preparation as an active ingredient. Progesterone gets mainly metabolised in the liver and gets excreted through urine and faeces. However, some part also does get excreted through the sweat. Offensive odour to the sweat due to Implanon is not a commonly reported problem. In the armpit, the amount of sweat is rather excessive. It gets stagnated there due to hair. You may try keeping the armpit cleanly shaved and apply good fragrance talcum powder. Still if the odour persists, you have following options: 1. Use underarm deodorants which will mask the odour of the sweat. 2. Switch over to some other method of contraception. However, if you switch over to any other hormonal contraception, it will cause the same problem, since they contain progestational products. Therefore if at all you are switching over, you have options like condom (male or female) or intrauterine (non-hormonal) contraceptive device like Copper T. I hope this provides you the valid and useful options. Dr. Nishikant Shrotri