Insulin is a physiological hormone with an indispensable role in carbohydrate metabolism. Its deficiency, due to partial or complete lack of secretion from the pancreas, represents a growing health problem characterized by hyperglycemia and reduced sensitivity of receptors in peripheral tissues to insulin. Insulin preparations have been used for insulin replacement over the past 100 years. Following animal-derived insulin, today, insulin analogs obtained through recombinant DNA technology and modified to act quickly and short-term or long-term are in use. The development of insulin as a drug continues. New and improved formulations of existing insulin analogs are being developed, administration is being simplified, and efforts are ongoing to find alternatives to subcutaneous injection, which is the biggest drawback and source of discomfort for most patients. Due to its well-known anabolic properties, insulin is also abused as a doping agent. This practice is most common in bodybuilding, often in combination with other agents to enhance muscle mass, appearance, and overall athletic performance. However, this neglects the health risks and long-term consequences of using insulin for non-medical purposes and without medical supervision.