Who Discovered GLP-1 Drugs? The Real History Behind Ozempic

There is no single inventor. The drugs in your pharmacy rest on about 120 years of work by people who mostly were not trying to build a weight-loss medicine.

Here is the actual chain, with the dates and the names, plus a correction to the most repeated myth about Ozempic.

Where does the story start?

In 1902, with two physiologists and a dog.

William Bayliss and Ernest Starling discovered secretin, a substance released by the intestine that acted on the pancreas through the bloodstream rather than through nerves [4]. That overturned Pavlov’s view that pancreatic secretion was purely nerve-controlled, and it founded the entire concept of a hormone.

Once you accept that the gut can send chemical messages to the pancreas, the next question follows naturally: does it send a message about insulin?

In 1932, Belgian physiologist Jean La Barre coined the word “incretin” - from INtestine seCRETion INsulin - for a hypothetical gut hormone that stimulates the endocrine pancreas [4][5]. The idea then sat unproven for three decades because nobody could measure insulin accurately.

When was the incretin effect proven?

In 1964, once radioimmunoassay made insulin measurable.

Two groups, McIntyre’s and Elrick’s, independently showed the same thing: swallowed glucose produces a much bigger insulin response than the same amount of glucose given intravenously, even at matched blood glucose levels [5]. Perley and Kipnis went on to show that this extra response is driven by gut-derived endocrine factors and accounts for more than half of the insulin response in healthy people [4].

That gap has a name - the incretin effect - and finding the hormones responsible became the project.

How was GLP-1 actually found?

Not by grinding up tissue. By reading DNA.

In the early 1980s, Joel Habener’s laboratory at Massachusetts General Hospital used the new tools of recombinant DNA to isolate proglucagon sequences from anglerfish [1]. In 1983, Graeme Bell reported the corresponding sequences from hamster, cow and human, and the picture became clear: glucagon is carved out of a much larger precursor protein, and hidden alongside it are two peptide sequences nobody had known existed [1].

They were named glucagon-like peptide-1 and glucagon-like peptide-2.

Now came the hard part. The precursor could in principle yield several versions of GLP-1 - the full-length GLP-1(1-37), the shortened GLP-1(7-37), and amidated variants. Which one, if any, was the real hormone?

Svetlana Mojsov, a peptide chemist then at Massachusetts General Hospital and later at The Rockefeller University, made the fragments synthetically and raised the antibodies needed to detect them [9]. Without pure, defined peptides and a way to measure them, the question could not be answered.

Daniel Drucker, then a fellow in Habener’s lab, ran the biology. In 1987 he showed that GLP-1(7-37) directly stimulates cyclic AMP accumulation, insulin gene expression and glucose-dependent insulin secretion in islet cells [1]. That was the moment a predicted peptide became a drug target.

In Copenhagen, Jens Juul Holst’s group isolated naturally occurring GLP-1(7-36)amide from intestinal extracts, demonstrated that GLP-1 suppresses glucagon - a property the other incretin, GIP, lacks - and identified the enzyme DPP-4 as the reason GLP-1 vanishes in about two minutes [1].

And in December 1987, Kreymann and Bloom demonstrated GLP-1’s insulin-boosting action in human subjects for the first time [1].

Five labs, one hormone, roughly four years.

Why did it take another twenty years to get a drug?

Because two minutes is not long enough.

DPP-4 clips two amino acids off GLP-1’s front end almost immediately [1]. The Copenhagen group proved the therapeutic concept anyway: in 2002 they infused synthetic GLP-1 continuously for six weeks and saw improved glucose control, reduced body weight and better beta-cell function, with no loss of effect over time [1].

It worked beautifully. It also required a continuous infusion pump, which is not a treatment anybody wants.

Where does the Gila monster come in?

This is the part everyone half-remembers, usually wrongly.

John Eng, an endocrinologist at the Bronx Veterans Affairs Medical Center, was intrigued that the Gila monster - a venomous lizard native to the American Southwest - can go long stretches without eating while keeping its blood sugar stable [6]. In 1992 he assayed its venom and isolated a peptide he named exendin-4, which triggers insulin release from pancreatic beta cells [6].

Exendin-4 shares only about half its sequence with human GLP-1, but it activates the same receptor. And because its sequence differs at the spot DPP-4 attacks, it naturally survives far longer than the human hormone.

Eng could not interest a large company. He set up a booth at an American Diabetes Association annual meeting, where a small biotech called Amylin Pharmaceuticals noticed it [7]. The resulting drug, exenatide, was approved by the FDA in 2005 as Byetta - the first GLP-1 receptor agonist ever marketed [7]. Eng later received a Golden Goose Award for the work [7].

So is Ozempic made from lizard venom? No. Semaglutide is a modified analog of the human GLP-1 sequence. Exenatide is the lizard-derived one, and it is a different drug from a different company. The confusion is understandable and extremely common, but the two molecules are not related beyond sharing a receptor.

Who turned GLP-1 into a once-weekly drug?

Novo Nordisk, through chemistry led by Lotte Bjerre Knudsen.

Her team’s approach was to attach a fatty acid to the peptide so it would bind reversibly to albumin in the blood, creating a slow-release reservoir and shielding the molecule from kidney clearance. The first product of that approach was liraglutide, a daily injection with a half-life of 13 to 15 hours.

Semaglutide refined it. Where liraglutide carries a 16-carbon mono-acid, semaglutide carries an 18-carbon diacid on a longer, more water-friendly spacer, giving much tighter albumin binding. Add an amino-acid substitution that blocks DPP-4, and the half-life jumps from hours to about a week.

Knudsen also pushed the argument that GLP-1 medicines should be developed for obesity, not only for diabetes. Her 2024 Lasker citation credits her specifically for “developing sustained acting versions of this hormone as a treatment for obesity” [2].

What did the awards recognize?

The 2024 Lasker-DeBakey Clinical Medical Research Award went to Joel Habener and Svetlana Mojsov for the discovery of GLP-1(7-37), and to Lotte Bjerre Knudsen for turning it into an obesity medicine [2][13]. The Lasker is often treated as a Nobel bellwether.

The 2025 Breakthrough Prize in Life Sciences widened the circle to five: Daniel Drucker, Joel Habener, Jens Juul Holst, Lotte Bjerre Knudsen and Svetlana Mojsov, “for their complementary contributions - from basic hormone discovery through physiological understanding to pharmaceutical development” [3].

The Nobel Prize has not gone to GLP-1. The 2025 Physiology or Medicine prize was awarded to Mary Brunkow, Frederick Ramsdell and Shimon Sakaguchi for discoveries concerning peripheral immune tolerance [10]. The 2026 prize had not been announced as of September 14, 2026. GLP-1 remains one of the most-cited contenders that has not won.

Mojsov’s inclusion in these awards followed years of effort. Early accounts of the discovery frequently omitted her contribution, and Science magazine covered her fight for recognition in 2023 [8].

What are the key dates?

Year	What happened
1902	Bayliss and Starling discover secretin, founding the hormone concept [4]
1932	La Barre coins “incretin” [4]
1964	McIntyre and Elrick independently demonstrate the incretin effect [5]
1983	Bell reports hamster, bovine and human proglucagon sequences [1]
1986-87	Mojsov, Habener, Drucker and Holst identify the active GLP-1 fragments [1]
Dec 1987	Kreymann and Bloom show GLP-1’s insulin effect in humans [1]
1992	John Eng isolates exendin-4 from Gila monster venom [6]
2002	Six-week GLP-1 infusion study proves the therapeutic concept [1]
2005	Exenatide (Byetta) approved - first GLP-1 receptor agonist [7]
2010-01-25	FDA approves liraglutide as Victoza, the first human GLP-1 analog [14]
2014-09-18	FDA approves dulaglutide (Trulicity), a weekly Fc-fusion GLP-1 [15]
2014-12-23	FDA approves liraglutide 3.0 mg as Saxenda, the first GLP-1 for obesity [14]
2017-12-05	FDA approves Ozempic (semaglutide injection) [11]
2019-09-20	FDA approves Rybelsus, first oral GLP-1 [11]
2021-06-04	FDA approves Wegovy for chronic weight management [11]
2024-09	Lasker Award for GLP-1 [2]
2025	Breakthrough Prize in Life Sciences for GLP-1 [3]
2025-12-22	FDA approves the Wegovy pill, first oral GLP-1 for weight management
2026-01-30	FDA approves renaming the higher-bioavailability oral semaglutide from Rybelsus to Ozempic tablets
2026-03-19	FDA approves Wegovy HD (semaglutide 7.2 mg), the first GLP-1 cleared under the Commissioner’s National Priority Voucher pilot
2026-04-01	FDA approves orforglipron (Foundayo), the first small-molecule oral GLP-1
2026-04-28	Health Canada authorizes the first generic semaglutide in the G7

What is the lesson in this history?

Three things, really.

The first is that nobody set out to make a weight-loss drug. Every step from 1902 to 1987 was about understanding how the gut talks to the pancreas. The obesity application was a consequence, not a plan.

The second is that basic science, peptide chemistry, physiology and industrial process development were all necessary, and none of them alone was sufficient. The prizes recognizing five people across four countries are an accurate reflection of how the work actually happened.

The third is that odd questions pay off. A physiologist wondering why a desert lizard can fast for months produced the first drug in a class now used by millions - and got there, in part, by renting a booth at a conference because nobody would return his calls.

Sources

1. Drucker, Discovery, characterization and clinical development of the glucagon-like peptides - Journal of Clinical Investigation
2. GLP-1-based therapy for obesity, 2024 Lasker-DeBakey Award citation - Lasker Foundation
3. Breakthrough Prize Announces 2025 Laureates in Life Sciences - Breakthrough Prize
4. The Origin and Understanding of the Incretin Concept - Frontiers in Endocrinology
5. Incretin-Based Therapies Through the Decades - Medical Sciences
6. Exendin-4: From lizard to laboratory… and beyond - National Institute on Aging
7. Dr. John Eng to receive Golden Goose Award - EurekAlert
8. Her work paved the way for blockbuster obesity drugs. Now, she’s fighting for recognition - Science
9. Svetlana Mojsov wins the 2024 Lasker~DeBakey Clinical Medical Research Award - The Rockefeller University
10. The Nobel Prize in Physiology or Medicine 2025 - NobelPrize.org
11. Ozempic (semaglutide) FDA Approval History - Drugs.com
12. The discovery and development of GLP-1 based drugs - PMC
13. Habener, Mojsov and Knudsen awarded Lasker prize - Journal of Clinical Investigation
14. Saxenda (liraglutide) FDA Approval History - Drugs.com
15. Trulicity (dulaglutide) BLA approval letter, September 18, 2014 - FDA