Summary
The history of peptide research is a chain of enabling breakthroughs, each one making the next possible. It begins with the recognition that the body uses short chains of amino acids as messengers, accelerates with the life-saving isolation of insulin in 1921, and matures through a sequence of technical revolutions: the first chemical synthesis of a peptide hormone (oxytocin) in the 1950s, solid-phase peptide synthesis in 1963, the radioimmunoassay that let scientists measure hormones present in vanishingly small amounts, and recombinant DNA that let bacteria manufacture human insulin. The modern era — GLP-1 drugs, long-acting formulations, and multi-agonist peptides — is the direct descendant of these milestones. This article traces that arc as a history of the field and its methods rather than a roster of individuals; for the people, see the scientists who changed peptide research.
Key Takeaways
- The word peptide and the idea that proteins are chains of amino acids joined by peptide bonds date to the very start of the 20th century, framing everything that followed.
- The isolation of insulin in 1921–1922 was the first great peptide-medicine breakthrough, converting a fatal disease into a manageable one and proving peptides could be therapeutic.
- The first chemical synthesis of a peptide hormone — oxytocin — in the 1950s showed that these molecules could be built in the lab, not just extracted from tissue.
- Solid-phase peptide synthesis (1963) made synthesis systematic and automatable; it remains the foundation of how research peptides are made — see the pioneers who built the field.
- Radioimmunoassay solved the measurement problem, letting scientists detect hormones present in trace amounts and accelerating endocrine discovery.
- Recombinant DNA technology in the late 1970s–1980s allowed human insulin and later many peptide hormones to be manufactured biologically at scale.
- The GLP-1 / incretin era and today's multi-agonist and long-acting designs are the current chapter of a continuous, century-long story.
- This is educational history; the peptides discussed elsewhere on this site remain strictly research-use-only, not for human consumption.
Before the beginning: what a peptide even is
To understand the history of peptide research, it helps to start with the idea at its center. A peptide is a short chain of amino acids linked by peptide bonds — the same type of bond that holds proteins together. The distinction between a peptide and a protein is mostly one of size and behavior: peptides are short and often act as signaling molecules, while proteins are longer and frequently do structural or enzymatic work. For a fuller primer, see what peptides are and how they compare to proteins, biologics, and small molecules.
This foundational concept was not obvious. At the turn of the 20th century, the German chemist Emil Fischer proposed that amino acids are joined end to end through what he named the peptide bond, giving the field both its central concept and its vocabulary. Fischer's work established that proteins are, in effect, long peptide chains, and it set the intellectual stage for everyone who followed. Without the peptide-bond concept, there would have been nothing to isolate, sequence, or synthesize.
The rest of the century can be read as a series of answers to three linked questions that this foundational insight raised. First: which peptides does the body actually make, and what do they do? Second: how can we detect and measure molecules that exist in the body in almost impossibly small quantities? Third: how can we build these molecules ourselves, reliably and at scale, so they can be studied and eventually used as medicines? The milestones below are, in essence, the moments those questions were answered.
Educational history, not medical advice
This article is an educational history of a scientific field. It is not medical advice. Peptides sold and discussed elsewhere on this site are strictly research-use-only — not for human consumption. Nothing here should be read as guidance for using any peptide.
1921: insulin and the first peptide medicine
If peptide medicine has a birthday, it is arguably 1921, when a small team in Toronto — Frederick Banting and Charles Best, working with J. J. R. Macleod and the biochemist James Collip — isolated a pancreatic extract that could lower blood sugar. Before insulin, type 1 diabetes was a death sentence; children diagnosed with it typically survived only months. Within a couple of years of that discovery, patients were being treated, and a disease that had been uniformly fatal became one that could be managed for a lifetime.
Insulin's significance for peptide research goes far beyond diabetes. It was the first clear demonstration that a peptide hormone could be extracted, purified, and used as a therapy — proof of concept for the entire idea of peptide medicine. The Nobel Prize in Physiology or Medicine was awarded for the discovery in 1923, remarkably fast recognition that reflected how immediately it transformed care. Insulin would go on to be a recurring protagonist in peptide history: it was among the first proteins to be sequenced, and later the first to be produced by recombinant DNA.
For decades after 1921, therapeutic insulin was purified from animal pancreases — chiefly pig and cattle. This worked but had limits: supply depended on slaughterhouse material, and animal insulin differs slightly from the human form. Those limitations would eventually be solved by two later revolutions in this story — chemical synthesis and recombinant production — but the essential lesson of 1921 stood: peptides could save lives. Everything that follows is, in one sense, an effort to make that lesson more general, more scalable, and more precise.
The 1950s: sequencing and the first synthesized hormone
The 1950s brought two milestones that, together, transformed peptides from mysterious extracts into defined chemical structures that could be read and rebuilt. The first was sequencing. Frederick Sanger determined the complete amino-acid sequence of insulin, showing for the first time that a protein has a precise, defined order of amino acids rather than some variable or random arrangement. This was a conceptual earthquake: it meant peptides and proteins had exact chemical identities that could, in principle, be written down and reproduced.
The second milestone was synthesis. Vincent du Vigneaud and his colleagues achieved the first laboratory synthesis of a peptide hormone — oxytocin, a nine-amino-acid peptide — and confirmed its structure by showing the synthetic molecule was biologically active. Du Vigneaud received the Nobel Prize in Chemistry in 1955 for this work on biologically important sulfur-containing compounds, including the synthesis of oxytocin. For the first time, a natural peptide hormone had been built from scratch and proven identical in function to the real thing.
The pairing of these advances was powerful. Sequencing told scientists exactly what a peptide was; synthesis let them make it. But early synthesis was still done in solution, one laborious step at a time, with the growing chain isolated and purified after every coupling. Building even a short peptide could take months, and longer ones were nearly impossible. The field had proven synthesis was achievable in principle — but making it practical would require an entirely new approach, which arrived in the next decade.
| Advance | What it established | Why it mattered |
|---|---|---|
| Insulin sequencing (Sanger) | Proteins have a defined, exact amino-acid sequence | Peptides became readable chemical structures, not vague extracts |
| Oxytocin synthesis (du Vigneaud) | A natural peptide hormone can be built in the lab and is biologically active | Proved peptides could be manufactured, not only extracted |
1963: solid-phase synthesis changes everything
The single most important technical breakthrough in the practical history of peptides came in 1963, when Bruce Merrifield introduced solid-phase peptide synthesis (SPPS). His insight was deceptively simple: instead of building a peptide in solution and isolating it after every step, anchor the first amino acid to a tiny insoluble bead and grow the chain outward from there. Because the peptide stayed attached to the solid support, excess reagents and byproducts could simply be washed away between steps — add an amino acid, wash, add the next, wash, repeat.
This turned an artisanal ordeal into a systematic, repeatable cycle. SPPS was fast and reliable enough to be automated, and Merrifield helped build early peptide-synthesizer machines. It scaled to targets that had been unthinkable, and it made peptide chemistry accessible to laboratories that could never have attempted month-long solution syntheses. Merrifield received the Nobel Prize in Chemistry in 1984 for developing chemical synthesis on a solid matrix. The deeper significance is that virtually every research peptide made today traces its methodology back to his idea — a point explored further in our profile of the field's pioneers.
SPPS did more than speed things up; it changed what questions researchers could ask. Once peptides could be made routinely, scientists could synthesize variants — swapping one amino acid for another — to probe how structure relates to function. This ability to iterate is the engine of modern peptide drug design: it is how researchers optimize stability, potency, and duration of action, themes that recur in the story of long-acting peptides and how new peptides are discovered.
Why 1963 is the hinge point
Before SPPS, peptide synthesis was a heroic, one-off feat. After it, synthesis became a repeatable industrial process. Almost everything in modern peptide research — from making research material to engineering drug candidates — depends on the method Merrifield introduced.
Radioimmunoassay: solving the measurement problem
Making peptides was one challenge; detecting them was another. Many of the body's most important peptide hormones circulate in extraordinarily low concentrations — far too dilute for the crude chemical assays of the mid-20th century. Without a way to measure them, discovering and studying these hormones was nearly impossible. The solution came in the late 1950s and 1960s with radioimmunoassay (RIA), developed by Rosalyn Yalow and Solomon Berson.
RIA used antibodies and radioactive tracers to measure hormone concentrations with unprecedented sensitivity, detecting substances present in tiny quantities that had previously been invisible. Yalow received the Nobel Prize in Physiology or Medicine in 1977 for the development of radioimmunoassays of peptide hormones. The technique was revolutionary not only for what it could measure but for how broadly it applied: it became a workhorse of endocrinology, enabling the detection and study of a whole universe of hormones.
The importance of RIA to peptide history is easy to underappreciate. The great wave of hypothalamic-hormone discoveries in the 1960s and 1970s — the isolation of releasing hormones that control the pituitary — depended on being able to detect these molecules in the first place. In this sense measurement and discovery advanced together: the ability to see tiny hormones made it possible to hunt them down, purify them, and eventually turn them into medicines.
The 1960s–70s: the brain's peptide hormones
With synthesis and measurement problems solved, the 1960s and 1970s became a golden age of peptide-hormone discovery. Roger Guillemin and Andrew Schally, working as fierce rivals, set out to prove that the hypothalamus controls the pituitary gland — and much of the body's hormonal system — by releasing tiny peptide signals. The quantities involved were so small that both teams had to process enormous amounts of animal tissue to isolate even a trace of each hormone.
Their combined work identified key hypothalamic releasing hormones, including thyrotropin-releasing hormone (TRH), gonadotropin-releasing hormone (GnRH, also called LHRH), and somatostatin. This founded the field of neuroendocrinology — the study of how the brain governs the endocrine system through peptides. Guillemin and Schally shared the 1977 Nobel Prize in Physiology or Medicine, awarded the same year as Yalow's recognition for RIA, underscoring how tightly discovery and measurement were linked.
These discoveries were not merely academic. Analogs of GnRH became real medicines used to treat hormone-sensitive conditions including prostate cancer, and somatostatin analogs were developed to treat certain tumors and hormonal disorders. This established a template that would repeat throughout peptide history: understand a natural peptide's role, then engineer an analog with improved properties into a therapy. The people behind this era are profiled in more depth in the scientists who changed peptide research.
Gut peptides join the story
Alongside the brain's hormones, researchers such as Viktor Mutt isolated and characterized peptide hormones of the gastrointestinal tract. This gut-peptide work would later prove crucial, because the incretin hormones behind today's metabolic drugs — including GLP-1 — come from the gut.
The 1980s: recombinant DNA and biological manufacturing
The next revolution was not in chemistry but in biology. Recombinant DNA technology, developed in the 1970s, made it possible to insert a human gene into bacteria and have those bacteria manufacture a human protein. In the late 1970s and early 1980s this was applied to insulin: human insulin produced in genetically engineered bacteria became one of the first recombinant-DNA drugs, ending the reliance on animal pancreases and providing a scalable, human-identical supply.
Recombinant production changed the economics and possibilities of peptide and protein medicine. For larger peptides and proteins, biological manufacturing could produce material at scales and consistencies that chemical synthesis struggled to match. It also opened the door to producing many other peptide and protein hormones biologically. Meanwhile, chemical synthesis via SPPS remained the method of choice for shorter peptides and for making the engineered variants that drug designers needed to test.
The 1980s therefore left peptide science with two complementary manufacturing routes — chemical synthesis for shorter, highly engineered peptides, and recombinant biology for larger or high-volume products. This dual toolkit is essentially what the field still uses. It set the stage for the final act of the century-long story: the deliberate engineering of peptides into drugs with tailored stability and duration, which would culminate in the incretin era.
| Method | Best suited to | Introduced / matured |
|---|---|---|
| Solid-phase peptide synthesis (SPPS) | Shorter peptides and engineered analogs | 1963 onward |
| Recombinant DNA production | Larger peptides/proteins and high-volume products (e.g. insulin) | Late 1970s–1980s |
The GLP-1 era and modern peptide design
The modern chapter of peptide history is built on the incretin hormones — gut peptides, chiefly GLP-1 (glucagon-like peptide-1), that stimulate insulin release, promote satiety, and slow gastric emptying. The biology of GLP-1 was worked out over the 1980s and 1990s, revealing a hormone with powerful effects on glucose control and appetite. There was, however, a catch: native GLP-1 is broken down within minutes by the enzyme DPP-4, making the natural hormone useless as a practical drug.
Solving that durability problem is where the whole history converges. Using the accumulated toolkit — synthesis, sequencing, structural understanding, and decades of experience engineering analogs — researchers designed GLP-1 receptor agonists resistant to rapid degradation and, later, formulations that last for a week or longer. Techniques such as fatty-acid attachment (lipidation) to promote albumin binding extended half-life dramatically, a subject explored in our guide to long-acting peptides. The result was a class of peptide drugs that reshaped the treatment of diabetes and obesity.
The frontier now is polypharmacology: single peptides engineered to activate several hormone receptors at once. Dual GLP-1/GIP agonists and triple GLP-1/GIP/glucagon agonists aim to amplify metabolic benefit beyond what any single-target drug can achieve — the subject of the science of multi-agonist peptides. For the biology of the peptides themselves, see semaglutide, tirzepatide, and retatrutide. Every one of these designs rests on the century of milestones that came before it.
A continuous chain
The GLP-1 era did not appear from nowhere. It required knowing peptides could be therapeutic (insulin), being able to build and vary them (synthesis and SPPS), understanding gut and brain hormones (neuroendocrinology and gut-peptide research), and being able to manufacture them at scale (SPPS and recombinant DNA). Each earlier milestone was a prerequisite.
Why this history still matters
Read as a whole, the history of peptide research is a story of compounding capability. Each breakthrough removed a barrier and exposed the next one: proving peptides could be drugs (insulin) revealed the need to define and build them (sequencing and synthesis); building them revealed the need to detect them (radioimmunoassay); detecting them enabled the great wave of hormone discovery; and manufacturing plus design turned those hormones into the medicines dominating headlines today.
Understanding this arc also clarifies why the field is moving so fast now. The tools accumulated over a century — reliable synthesis, structural knowledge, half-life engineering, recombinant production, and increasingly computational design — are being combined and applied to new targets and delivery routes. That is why we now see progress toward oral peptide delivery, nasal delivery, and the broader race to replace injectable peptides.
Finally, the history is a reminder that today's research peptides sit within a long scientific tradition — one grounded in careful measurement, honest characterization, and reproducibility. For anyone studying peptides, that heritage translates into practical priorities: knowing what a molecule is, verifying its identity and purity, and handling it correctly. To see who made this history, continue with the scientists who changed peptide research, and for the concentrated four-person account, see the pioneers of peptide science.
Timeline
circa 1901–1906
The peptide bond named
Emil Fischer's work establishes that amino acids join via peptide bonds and that proteins are peptide chains, giving the field its central concept and vocabulary.
1921–1922
Insulin isolated
Banting, Best, Macleod, and Collip isolate insulin in Toronto, transforming type 1 diabetes from a fatal disease into a manageable one — the first great peptide medicine.
1950s
Sequencing and first hormone synthesis
Frederick Sanger sequences insulin; Vincent du Vigneaud synthesizes oxytocin, the first laboratory synthesis of a peptide hormone (Nobel Prize in Chemistry, 1955).
1963
Solid-phase peptide synthesis
Bruce Merrifield introduces SPPS, making peptide synthesis systematic, repeatable, and automatable — the foundation of modern peptide chemistry.
1950s–1970s
Radioimmunoassay
Rosalyn Yalow and Solomon Berson develop RIA, enabling ultra-sensitive measurement of peptide hormones and accelerating endocrine discovery.
1960s–1970s
Hypothalamic hormones discovered
Guillemin and Schally isolate releasing hormones (TRH, GnRH, somatostatin), founding neuroendocrinology; they share the 1977 Nobel Prize with Yalow.
Late 1970s–1980s
Recombinant human insulin
Recombinant DNA technology lets bacteria manufacture human insulin, ending reliance on animal pancreases and enabling scalable biological production.
1980s–2000s
The GLP-1 / incretin era
Incretin biology is worked out and degradation-resistant GLP-1 receptor agonists are engineered, launching a transformative class of metabolic drugs.
2010s–2020s
Multi-agonists and long-acting design
Single peptides engineered to hit multiple receptors, plus long-acting and non-injectable delivery, extend the century-old foundations into the present.
Frequently Asked Questions
When did peptide research begin?
The conceptual foundation dates to the very start of the 20th century, when Emil Fischer established that amino acids join through peptide bonds and that proteins are peptide chains. The first major medical milestone came in 1921–1922 with the isolation of insulin, widely regarded as the beginning of peptide medicine.
Why was the discovery of insulin so important for peptide science?
Insulin was the first clear proof that a peptide hormone could be extracted, purified, and used as a therapy, converting fatal type 1 diabetes into a manageable condition. It served as proof of concept for the entire idea of peptide medicine and later became the first protein to be sequenced and the first to be made by recombinant DNA.
What was the first peptide hormone to be chemically synthesized?
Oxytocin, a nine-amino-acid peptide, was the first peptide hormone synthesized in the laboratory, achieved by Vincent du Vigneaud and colleagues in the 1950s. Du Vigneaud received the 1955 Nobel Prize in Chemistry for this work, which proved that natural peptide hormones could be built from scratch and shown to be biologically active.
Why is 1963 considered a turning point?
In 1963 Bruce Merrifield introduced solid-phase peptide synthesis (SPPS), which anchors the peptide to an insoluble bead so byproducts can be washed away between steps. This turned synthesis from a months-long ordeal into a fast, repeatable, automatable process and remains the foundation of how research peptides are made today.
What role did radioimmunoassay play in peptide history?
Radioimmunoassay (RIA), developed by Rosalyn Yalow and Solomon Berson, allowed scientists to measure peptide hormones present in extremely small amounts. This solved the measurement problem and enabled the great wave of hormone discovery in the 1960s and 1970s. Yalow received the 1977 Nobel Prize in Physiology or Medicine for it.
How did recombinant DNA change peptide manufacturing?
Recombinant DNA technology let genetically engineered bacteria produce human proteins. Applied to insulin in the late 1970s and early 1980s, it provided a scalable, human-identical supply and ended reliance on animal pancreases. It gave the field a second manufacturing route alongside chemical synthesis, especially useful for larger or high-volume products.
How does modern GLP-1 drug design connect to earlier history?
GLP-1 drugs depend on everything that came before: the knowledge that peptides can be therapeutic (insulin), the ability to build and vary them (synthesis and SPPS), an understanding of gut and brain hormones (neuroendocrinology and gut-peptide research), and scalable manufacturing. Solving GLP-1's rapid degradation with half-life-extension techniques produced today's transformative metabolic medicines.
Is this article about specific scientists?
This article focuses on the history of the field and its techniques and milestones. For a profile-driven account of the individual researchers who drove these advances, see the companion article, the scientists who changed peptide research, and the concentrated four-person account in the pioneers of peptide science.
References
- The Nobel Prize in Physiology or Medicine 1923 — Frederick Banting and John Macleod, for the discovery of insulin. Official prize information.Source
- The Nobel Prize in Chemistry 1955 — Vincent du Vigneaud, for work on biochemically important sulphur compounds, especially the first synthesis of a polypeptide hormone. Official prize information.Source
- The Nobel Prize in Chemistry 1984 — Bruce Merrifield, for methodology of chemical synthesis on a solid matrix. Official prize information.Source
- The Nobel Prize in Physiology or Medicine 1977 — Roger Guillemin and Andrew Schally (peptide hormone production of the brain) and Rosalyn Yalow (radioimmunoassay). Official prize information.Source
- Sanger, F. The chemistry of insulin — determination of the amino-acid sequence of a protein (foundational sequencing work).Source
- Merrifield, R. B. Solid Phase Peptide Synthesis. I. The Synthesis of a Tetrapeptide. Journal of the American Chemical Society (1963).Source
- Reviews of recombinant human insulin and the origins of biotechnology-based protein manufacturing (peer-reviewed literature).Source
- Reviews of GLP-1 / incretin biology and the development of GLP-1 receptor agonist therapeutics (peer-reviewed endocrinology and pharmacology literature).Source
Research & Educational Use Only
This article is for general educational and informational purposes only and is not legal, medical, or regulatory advice. Laws and FDA policy change; verify the current status of any compound with primary FDA sources and a qualified professional before acting. Peptides discussed here are sold for research use only and are not intended for human consumption, diagnosis, treatment, or prevention of disease.