Zoladex may stay in your system for up to 12 weeks.The Zoladex implant is designed to dissolve over time.
For instance, at 28 days, a 3.6-milligram (mg) Zoladex implant is nearly gone and all the medication has nearly been used up. However, in clinical studies, it took up to 12 weeks after the last implant was inserted for hormone levels to return to normal.