Nandrolone decanoate is an anabolic steroid commonly used to treat conditions like anemia, osteoporosis, and muscle wasting diseases. It promotes muscle growth, increases red blood cell production, and enhances bone density. Athletes and bodybuilders may use it (illegally in some regions) to improve strength, endurance, and muscle mass. Its long-acting nature makes it effective for sustained results. However, medical supervision is essential due to potential side effects like hormonal imbalance and cardiovascular risks.