Pharmacology & biology

GLP-1

Also known as: glucagon-like peptide-1 · glp1 · glp-1 receptor agonist · glp-1ra

Glucagon-like peptide-1 — an incretin hormone that increases insulin secretion, slows gastric emptying, and reduces appetite.

In plain terms

GLP-1 acts in the pancreas, the gut, and the brain. The appetite effect is largely central, which is why people describe a change in the desire to eat rather than a feeling of fullness alone.

Native GLP-1 is destroyed within minutes by the enzyme DPP-4. Every GLP-1 drug is an analog engineered to survive it.

Compounds where this comes up

Guides that use this term

Semaglutide vs tirzepatide: what the head-to-head trial found

SURMOUNT-5 compared them directly over 72 weeks: tirzepatide produced 20.2% weight loss versus 13.7% for semaglutide. What that number does and does not settle.

What happens when you stop a GLP-1

One year after semaglutide was withdrawn, participants had regained two-thirds of the weight they lost, and their cardiometabolic gains reverted. The withdrawal trials, read honestly.

Muscle loss on GLP-1s: what the evidence shows

A 2026 meta-analysis found lean mass falls in absolute terms on GLP-1 drugs while rising as a proportion of body weight. Both statements are true, and they explain the entire argument.

“Ozempic face”: what it is and what causes it

Facial gauntness after GLP-1 weight loss is caused by the weight loss, not by the drug. The same appearance follows rapid loss by any means — which is what the term obscures.

Sources

FDA — Concerns with unapproved GLP-1 drugs used for weight loss

Educational reference only. Pepperz does not provide medical advice, diagnosis, treatment, prescribing guidance, or dosing recommendations.