The History of Peptides: From the First Hormone to the GLP-1 Era

Peptides feel like a 2020s phenomenon. They are not. The science behind the compounds filling medicine cabinets and message boards today is more than a century old, and it runs through some of the most important discoveries in modern biology. Understanding where peptides came from, and how fast the field is now accelerating, makes the current moment a lot easier to read.

This is the long view. If you have ever wondered when peptides were discovered, who discovered them, or how the field went from a single 1902 experiment to the GLP-1 explosion of the 2020s, this is the full history of peptides, with a complete timeline of the milestones that got us here.

1902: The Birth of Hormone Science

The story starts in a London laboratory. In 1902, physiologists William Bayliss and Ernest Starling identified a substance released by the small intestine that triggered the pancreas to secrete digestive fluid. They named it secretin, and it was a peptide. Three years later Starling coined a word for this new class of chemical messengers: hormone, from the Greek for "to arouse."

That single discovery created the entire field of endocrinology and established the core idea that would define peptide science for the next century. Small chains of amino acids can carry powerful biological signals. Secretin itself never became a blockbuster, but the door it opened led directly to the first true miracle drug.

1921 to 1922: Insulin, the First Peptide Medicine

Before insulin, a diagnosis of type 1 diabetes was a death sentence, usually within months. In the summer of 1921, at the University of Toronto, Frederick Banting and Charles Best, working under J.J.R. Macleod and with crucial purification help from biochemist James Collip, isolated insulin from pancreatic extract. On January 11, 1922, a 14-year-old patient named Leonard Thompson became the first person treated. His blood sugar dropped, and a fatal disease became a manageable one almost overnight.

Insulin is a peptide hormone, and its arrival was the proof of concept for an entire industry. A naturally occurring peptide, extracted and administered, could save lives at scale. Banting and Macleod won the Nobel Prize in 1923. For the next fifty years, though, insulin still had to be harvested from animal pancreases, a supply problem that would only be solved by two more revolutions.

1951 to 1955: Cracking the Code

Before anyone could build peptides on purpose, they had to answer a basic question: what are peptides, exactly? That answer came from Frederick Sanger at Cambridge, who between 1951 and 1955 determined the complete amino-acid sequence of insulin, the first protein ever fully sequenced. It sounds abstract, but the implication was enormous. It proved that peptides and proteins are not vague blobs but precise, defined chains of amino acids in a specific order, and that the order is what gives each one its function.

Sanger won the Nobel Prize in 1958 for this work, the first of two he would win. His insight is the intellectual foundation of everything that followed. Once you know a peptide is a readable sequence, you can imagine reading it, writing it, and eventually designing it, which is exactly what the next seventy years would do.

1953 to 1963: Learning to Build Peptides From Scratch

The first revolution was chemical. In 1953, biochemist Vincent du Vigneaud synthesized oxytocin, the nine-amino-acid hormone behind labor and bonding, becoming the first person to build a peptide hormone in a laboratory rather than extract it from tissue. It earned him the 1955 Nobel Prize and proved that peptides were not just things you found in the body. They were things you could manufacture.

Then came the breakthrough that made the modern field possible. In 1963, Bruce Merrifield introduced solid-phase peptide synthesis (SPPS), a method of building peptide chains one amino acid at a time on a solid resin bead. It turned peptide synthesis from a painstaking art into a repeatable, automatable process. Merrifield won the Nobel Prize in 1984, and SPPS remains the backbone of how research and therapeutic peptides are made to this day. Nearly every compound in the current market traces its manufacturability back to this one innovation.

1978 to 1982: The Recombinant Revolution

The second revolution was biological. In 1978, the young biotech company Genentech used recombinant DNA technology to make human insulin inside genetically engineered bacteria. In 1982 it reached the market as Humulin, the first recombinant biopharmaceutical ever approved. Suddenly peptides and proteins did not have to be synthesized atom by atom or harvested from animals. They could be grown.

This is the moment peptides became a scalable industry. Recombinant production and SPPS together gave scientists two reliable ways to make almost any peptide they could design, and the 1980s and 1990s saw a wave of new therapeutic peptides move from lab to clinic.

1985 to the 1990s: The Therapeutic Expansion

With manufacturing solved, the pipeline filled. GnRH agonists like leuprolide (Lupron, approved 1985) transformed the treatment of prostate cancer and endometriosis. The somatostatin analog octreotide (Sandostatin, 1988) gave doctors a tool for rare hormonal tumors. Desmopressin, calcitonin, and a growing list of others established peptides as a serious, if specialized, therapeutic class.

This era also quietly seeded the research-peptide world. Compounds like BPC-157, a fragment derived from a protein found in gastric juice, were first studied in the 1990s for tissue repair. Growth-hormone-releasing peptides began appearing in the literature. These would not reach the mainstream for decades, but the science was being laid down.

1987 to 2010: The Incretin Discovery and the Road to GLP-1

The single most consequential thread in modern peptide history began in the late 1980s, when researchers characterized GLP-1 (glucagon-like peptide-1), a gut hormone that stimulates insulin release, slows stomach emptying, and reduces appetite. The problem was that natural GLP-1 breaks down in the body within minutes, making it useless as a drug on its own.

The first workaround came from an unlikely source. In the early 1990s, endocrinologist John Eng discovered that the venom of the Gila monster contained a peptide, exendin-4, that mimicked GLP-1 but lasted far longer. That research led to exenatide (Byetta), the first GLP-1 receptor agonist, approved in 2005. Liraglutide (Victoza) followed in 2010, extending the dosing from twice daily toward once daily. The race was now on to make GLP-1 drugs that lasted longer and worked better.

2017 to 2023: The GLP-1 Explosion

Everything changed with semaglutide. Approved as Ozempic for type 2 diabetes in 2017, it offered once-weekly dosing and striking results. But the inflection point came in 2021, when semaglutide was approved as Wegovy specifically for weight management. That was the moment a peptide drug crossed from diabetes clinics into the broader culture, and semaglutide became a household name.

Eli Lilly's tirzepatide, a dual GIP/GLP-1 agonist, raised the bar again, launching as Mounjaro for diabetes in 2022 and Zepbound for weight management in 2023, with weight-loss results that exceeded semaglutide's in head-to-head trials. Our tirzepatide and Mounjaro vs Ozempic breakdowns cover how the modern options actually differ. In the span of two years, a 120-year-old field went from specialist medicine to one of the biggest stories in health.

The Parallel Track: Research Peptides Go Mainstream

While the pharmaceutical GLP-1 story played out, a second peptide world was growing alongside it, one born in bodybuilding, anti-aging, and biohacking communities. Growth-hormone secretagogues like CJC-1295 and ipamorelin, repair peptides like BPC-157 and TB-500, and cognitive and longevity compounds moved through a network of research-chemical suppliers, compounding pharmacies, and word-of-mouth protocols. This track has always run ahead of formal regulation, and it is where much of today's fast-moving experimentation happens.

A Peptide Timeline

Year	Milestone
1902	Bayliss and Starling discover secretin, the first hormone and a peptide
1905	Starling coins the word "hormone"
1921-22	Insulin isolated in Toronto; first patient treated in Jan 1922, the first peptide medicine
1923	Nobel Prize awarded for insulin
1951-55	Sanger sequences insulin, the first protein sequenced, proving peptides are defined amino-acid chains
1953	du Vigneaud synthesizes oxytocin, the first lab-built peptide hormone
1963	Merrifield invents solid-phase peptide synthesis (SPPS), the manufacturing revolution
1978	Genentech produces recombinant human insulin
1982	Humulin approved, the first recombinant biopharmaceutical
1985	Leuprolide (Lupron) approved, a GnRH agonist
1988	Octreotide (Sandostatin) approved, a somatostatin analog
Late 1980s	GLP-1 characterized as an incretin hormone
1990s	BPC-157 and GH-releasing peptides enter the research literature
2005	Exenatide (Byetta) approved, the first GLP-1 receptor agonist, from Gila monster venom
2010	Liraglutide (Victoza) approved
2017	Semaglutide (Ozempic) approved for type 2 diabetes
2021	Semaglutide (Wegovy) approved for weight management, the cultural inflection point
2022	Tirzepatide (Mounjaro) approved for diabetes
2023	Tirzepatide (Zepbound) approved for weight management
2024-2026	GLP-1 use goes mainstream; compounded and research-peptide markets surge

Why It's Moving So Fast Now

Step back and the acceleration makes sense. It took decades to answer the field's foundational questions: what peptides are, how to build them, how to manufacture them at scale. Those problems are now solved. When GLP-1 drugs proved that a peptide could deliver mass-market results, the entire century of accumulated infrastructure, the synthesis, manufacturing, delivery, and regulation, was ready to move fast behind it. What used to take thirty years now takes three.

That is why 2026 feels like a different world than 2016, and why the pace shows no sign of slowing. The compounds keep multiplying, the audience keeps widening, and the people running these protocols increasingly want the same thing the pioneers wanted: a clear, organized record of what they are actually taking and how it is going. That is exactly what Dosi was built for, one place to keep the whole history straight as the field races ahead. Search Dosi Health in the App Store to start.