What “endogenous” means
Endogenous means made inside your own body. It’s the word scientists use to distinguish the hormones, enzymes, and other molecules you produce yourself from anything introduced from the outside. Your endogenous GLP-1, for example, is released by cells in your gut after a meal — it’s an incretin hormone that helps trigger insulin and signal fullness. The direct opposite is exogenous: something that comes from outside, such as a medication.
Why it matters if you’re on a GLP-1
The phrase you’ll run into is “endogenous vs exogenous GLP-1,” and the distinction is the whole reason GLP-1 medications work the way they do. Your endogenous GLP-1 does its job well but briefly — it’s broken down within minutes, so its effects on appetite are short-lived. GLP-1 drugs like semaglutide are exogenous: they deliver an engineered version of that same hormone, built to resist breakdown and last about a week. In other words, they’re not introducing something alien so much as supplying a longer-lasting copy of a signal your body already uses. The GLP-1 overview explains how that copy is put to work.
What to keep in mind
Because a medication amplifies a natural system rather than replacing it, your own endogenous hormones are still part of the picture, and how much benefit someone gets from an exogenous drug varies from person to person. “Endogenous” is really just vocabulary — a way to be precise about what’s homegrown and what’s added — but it makes the science behind these medications much easier to read.