What does GLP-1 stand for?

Glucagon-like peptide-1, a short peptide hormone made from the same precursor protein as glucagon.

Yes. Natural GLP-1 is a peptide hormone. Most GLP-1 drugs are modified peptides; orforglipron (Foundayo) is a non-peptide small molecule.

Is tirzepatide a GLP-1?

It activates both GLP-1 and GIP receptors, so it is a dual agonist, usually grouped with GLP-1 drugs.

Do foods or supplements raise GLP-1?

Protein and fibre cause modest, short-lived rises in your own GLP-1. No supplement comes close to the effect of GLP-1 drugs.

What are the main side effects of GLP-1 drugs?

Nausea, diarrhoea, vomiting and constipation are most common; pancreatitis and gallbladder disease are rarer serious risks.

What does GLP-1 do in the body?

It raises insulin when glucose is high, reduces glucagon, slows stomach emptying and increases fullness.

Ozempic is semaglutide, a GLP-1 receptor agonist: a long-acting drug that mimics the hormone.

What does GLP-1 do to your face?

The drugs do not act on the face directly, but rapid weight loss can reduce facial fat and make skin look looser, often called "Ozempic face".

What Is GLP-1? The Hormone and the Drugs Named After It

What is GLP-1? The gut hormone, how GLP-1 drugs like Ozempic and Zepbound mimic it, what they treat and common side effects. Not medical advice.

Anonymous user report. Not medical advice. Peptides discussed are not FDA-approved for the uses described. Editorial process →

Short answer

GLP-1 (glucagon-like peptide-1) is a hormone released by the gut after eating. It boosts insulin release when blood sugar is high, lowers glucagon, slows stomach emptying and signals fullness to the brain. Natural GLP-1 lasts only minutes in the blood. GLP-1 receptor agonist drugs — semaglutide (Ozempic, Wegovy, Rybelsus), liraglutide (Victoza, Saxenda), dulaglutide (Trulicity), the dual GLP-1/GIP drug tirzepatide (Mounjaro, Zepbound) and the pill orforglipron (Foundayo) — are engineered to act for a day to a week, which is why they lower blood sugar and appetite strongly enough to treat type 2 diabetes and obesity. Their main side effects are gastrointestinal. Peptide Confessions does not publish dosing, timing, injection or sourcing guidance.

The hormone vs the drugs

Natural GLP-1 is made by L-cells in the small intestine and colon within minutes of eating. The enzyme DPP-4 breaks it down in about two minutes, so its effects are brief. GLP-1 receptor agonist drugs are modified to resist that breakdown and stay active for about a day (liraglutide) or a week (semaglutide, dulaglutide, tirzepatide). That sustained, much stronger signal is what produces large effects on blood sugar and appetite.

	Natural GLP-1	GLP-1 drugs
Made by	Gut L-cells after meals	Manufactured peptide or small molecule
Lasts	About 2 minutes	About a day to a week
Effect on appetite	Mild, meal to meal	Strong and sustained
Examples	Your own hormone	Ozempic, Wegovy, Mounjaro, Zepbound and others

What GLP-1 does, organ by organ

Pancreas: more insulin when glucose is high and less glucagon, which is why the drugs rarely cause low blood sugar on their own. Stomach: slower emptying, so people feel full sooner; this also explains much of the nausea. Brain: GLP-1 receptors in appetite centres reduce hunger and what users call "food noise". Heart and kidneys: in large outcome trials, some GLP-1 drugs lowered major cardiovascular events in people with heart disease or diabetes, and semaglutide slowed kidney decline in people with diabetes and kidney disease.

What GLP-1 drugs are approved for

Type 2 diabetes (Ozempic, Rybelsus, Mounjaro, Trulicity, Victoza) and chronic weight management (Wegovy, Zepbound, Saxenda, Foundayo), plus cardiovascular, kidney or sleep-apnoea indications on specific labels. Other uses, such as addiction, are still being studied. See GLP-1 for weight loss for trial results.

Common and serious side effects

Most common: nausea, diarrhoea, vomiting, constipation and abdominal pain, usually worst when starting or increasing a dose. Serious label warnings: pancreatitis, gallbladder disease, kidney injury from dehydration, low blood sugar with insulin or sulfonylureas, and thyroid C-cell tumours in rodents. Fast weight loss can also bring hair shedding and "Ozempic face". More: GLP-1 side effects.

What users report here

Our semaglutide and tirzepatide files are small and self-selected. #686 describes less joint inflammation before any weight came off; #43 describes losing a third of their hair density over five months; #259 complains of "Ozempic zombie face". Browse the semaglutide reports and tirzepatide reports. These are stories, not rates.

Last reviewed

October 15, 2026.

More confessions from the archive

Community Q&A

What does GLP-1 stand for?: Glucagon-like peptide-1, a short peptide hormone made from the same precursor protein as glucagon.
Is GLP-1 a peptide?: Yes. Natural GLP-1 is a peptide hormone. Most GLP-1 drugs are modified peptides; orforglipron (Foundayo) is a non-peptide small molecule.
Is tirzepatide a GLP-1?: It activates both GLP-1 and GIP receptors, so it is a dual agonist, usually grouped with GLP-1 drugs.
Do foods or supplements raise GLP-1?: Protein and fibre cause modest, short-lived rises in your own GLP-1. No supplement comes close to the effect of GLP-1 drugs.
What are the main side effects of GLP-1 drugs?: Nausea, diarrhoea, vomiting and constipation are most common; pancreatitis and gallbladder disease are rarer serious risks.
What does GLP-1 do in the body?: It raises insulin when glucose is high, reduces glucagon, slows stomach emptying and increases fullness.
Is Ozempic GLP-1?: Ozempic is semaglutide, a GLP-1 receptor agonist: a long-acting drug that mimics the hormone.
Does this page give dosing advice?: Peptide Confessions does not publish dosing, timing, injection or sourcing guidance.
What does GLP-1 do to your face?: The drugs do not act on the face directly, but rapid weight loss can reduce facial fat and make skin look looser, often called "Ozempic face".

Sources

Anonymous first-hand reports plus sourced context — educational only, not medical advice. Editorial policy & corrections.