Supprelin LA starts to work within 4 weeks of implantation and by that time you should see signs that your child’s puberty is stopping. Do not be alarmed if during the first week of Supprelin LA treatment you an increase in signs of puberty in your child, such as light vaginal bleeding or breast enlargement in girls. This is to be expected because initially, Supprelin LA causes an increase in some hormones, but after 1 week, hormone levels decrease and puberty starts to abate.