API and raw material are often confused due to the similar usage of the two terms. What is the difference? Raw material refers to chemical compounds that are used as a base to make an API. The API is not made by only one reaction from the raw materials but rather it becomes an API via several chemical compounds. The chemical compound which is in the process of becoming an API from a raw material is called an intermediate. http://www.nmn-bio.com/biological-api/