### Question
How does the law define insulin?


### Answer
Under *21 CFR § 200.15*, **insulin** is defined as:

> the active principle of the pancreas that affects the metabolism of carbohydrates in the animal body and which is of value in the treatment of diabetes mellitus. 

#### Citation:
  - *21 CFR § 200.15*
  - Heading: **PART 200—GENERAL > Subpart A—General Provisions**

