Biological APIs, or biopharmaceuticals, are derived from living organisms, including humans, animals, or microorganisms. These APIs are produced using biotechnological methods, such as recombinant DNA technology, and are often more complex than synthetic APIs. Examples include monoclonal antibodies, insulin, and vaccines. Biological APIs have transformed therapeutic approaches, particularly in treating chronic and complex diseases like cancer and autoimmune disorders. However, they generally require more rigorous regulatory oversight due to their complex nature and immunogenic potential.