Levonorgestrel is a synthetic hormone used primarily in contraceptive methods. It is a progestin, which means it mimics the effects of the natural hormone progesterone in the body. Levonorgestrel is commonly found in birth control pills and emergency contraceptive pills, helping to prevent pregnancy by inhibiting ovulation and altering the uterine lining. In emergency contraception, levonorgestrel is most effective when taken within 72 hours after unprotected intercourse. It works by preventing fertilization or implantation of a fertilized egg. This medication is available over-the-counter in many countries, making it accessible for those who need it for emergency situations.