Question

why insulin is injected instead of being drunk as drugs

Answer 1

Answer: Insulin cannot be taken by mouth because it is digestible. Oral insulin would be obliterated in the stomach, long before it reached the bloodstream where it is needed. Once injected, it starts to work and is used up in a matter of hours.

Answer 2

Insulin cannot be taken orally because it would break down in the digestive process. Why Injection Is Better: Blood sugar levels are subject to great change throughout the day.