What Is GLP-1? The Simple Explanation Behind Ozempic

GLP-1 (glucagon-like peptide-1) is a hormone your gut makes every time you eat. It tells your pancreas to release insulin when blood sugar rises, slows down how fast your stomach empties, and signals your brain that you're full. Ozempic isn't GLP-1 itself. It's a lab-made version, semaglutide, designed to do the same job for a week instead of a couple of minutes.

That difference in timing is the whole story behind Ozempic, Wegovy and the rest of the GLP-1 drugs. Here's how the natural hormone works, why your own GLP-1 can't do what the medicine does, and what you can and can't do to raise it naturally.

Glucagon-like peptide-1. "Peptide" means it's a short chain of amino acids, a small protein. "Glucagon-like" is a historical label: it comes from the same gene as glucagon, the hormone that raises blood sugar, even though GLP-1 does mostly the opposite. The "1" separates it from GLP-2, a related hormone that works on the gut lining.

GLP-1 belongs to a family called incretins, hormones released from the gut after a meal that boost insulin. The other main incretin is GIP, which is why tirzepatide (Mounjaro, Zepbound), which acts on both, is sometimes called a dual incretin drug.

Most of your GLP-1 is made by L-cells lining the lower small intestine and colon. When food, especially protein, fat and fiber, reaches them, they release GLP-1 into the bloodstream within minutes. A smaller amount is made by nerve cells in the brainstem, where it helps regulate appetite and nausea.

The detail in the first row matters for safety. Because GLP-1 only boosts insulin when blood sugar is elevated, it rarely pushes blood sugar too low on its own. The risk of lows with GLP-1 drugs comes mainly from combining them with insulin or sulfonylureas.

Natural GLP-1 is broken down within about two minutes by an enzyme called DPP-4. It does its job in short bursts after each meal and then disappears. That's fine for normal digestion, but it's far too brief to change appetite or blood sugar for a whole day, let alone a week.

Scientists solved this in two ways. One approach blocks the DPP-4 enzyme so your own GLP-1 lasts a little longer; that's how diabetes pills like sitagliptin (Januvia) work, and their effect is modest. The other approach builds a GLP-1 look-alike that the enzyme can't easily break down. Semaglutide is about 94% similar to human GLP-1, with small changes that protect it from DPP-4 and help it bind to albumin in the blood, which stretches its half-life to about a week. Our guide to how Ozempic works goes deeper on that.

No, and the mix-up is common. GLP-1 is the natural hormone, and also the name of the drug class. Ozempic is one brand of one drug in that class. A simple way to keep them straight:

So "Is GLP-1 the same as Ozempic?" is a bit like asking whether "pain reliever" is the same as Advil. Ozempic is one example. Mounjaro, Zepbound, Trulicity, Victoza and Foundayo are others. See our full list of GLP-1 medications and our explainer on Ozempic vs semaglutide.

GLP-1 was identified in the 1980s. Svetlana Mojsov, Joel Habener and colleagues showed it was an active hormone that boosts insulin, and Lotte Bjerre Knudsen led work at Novo Nordisk that turned it into long-acting drugs. The three received the 2024 Lasker Award, one of medicine's top prizes, for that work.

The first GLP-1 drug, exenatide, came from an unexpected place: a compound found in the saliva of the Gila monster, a venomous lizard, that happens to activate the GLP-1 receptor and resist breakdown. It was approved in 2005. Liraglutide followed in 2010 as a daily shot, and semaglutide (Ozempic) was approved in December 2017 as a once-weekly injection.

A little, yes. Not to anything close to drug levels. Foods that reach the lower gut and take longer to digest prompt more GLP-1 release:

These habits are worth it for many reasons, but the effect on GLP-1 is measured in small, short-lived bumps. Supplements marketed as "GLP-1 boosters," including berberine, aren't proven to deliver anything like the effect of prescription drugs. If a product promises "natural Ozempic," treat that as marketing.

Not one used in everyday care. GLP-1 levels rise and fall within minutes after meals, so a single blood test says little, and research labs need special handling to measure it at all. There's no need to check your GLP-1 level before starting a GLP-1 drug. Decisions are based on blood sugar, weight, other conditions and your goals.

GLP-1 is a natural gut hormone that helps control blood sugar and appetite after you eat. On its own, it's gone in minutes. GLP-1 drugs like Ozempic copy it in a form that lasts a week, which is why they have such strong effects on blood sugar and weight. Diet can nudge your own GLP-1 a little, but it's not a substitute for the medicine, and anything sold as one should be viewed with skepticism.