How Were Peptides Discovered? A Timeline of the Breakthroughs Behind Modern Research Compounds

Every research peptide in a modern laboratory has a story — a moment when a scientist isolated a compound, noticed something unexpected, and opened a new chapter in biochemistry. Understanding how peptides were discovered is not just academic trivia. It reveals why certain compounds behave the way they do, why some are better documented than others, and which discoveries still shape active research programs today.

This timeline traces the major breakthroughs behind the research peptides used in laboratories worldwide — from a Nobel laureate’s first synthesis in 1901 to the triple-agonist compounds making headlines right now.

1901–1902: Emil Fischer Coins the Term “Peptide” and Synthesizes the First One

The entire field begins with German chemist Hermann Emil Fischer. In 1901, Fischer and his colleague Ernest Fourneau synthesized glycylglycine — the first peptide ever created in a laboratory. A year later, at a scientific congress in Karlsbad, Fischer formally introduced the term peptide to describe chains of amino acids linked by what he called peptide bonds.

Fischer received the Nobel Prize in Chemistry in 1902. Over the next decade, he and his collaborators synthesized roughly 100 peptides containing between 2 and 18 amino acid residues. His work established the foundational chemistry that every subsequent peptide discovery would build upon — the understanding that amino acids could be linked in specific sequences to produce biologically active molecules.

1953: The First Peptide Hormone Synthesis — Oxytocin

The next major milestone came half a century later when American biochemist Vincent du Vigneaud achieved the total chemical synthesis of oxytocin — a nine-amino-acid peptide hormone. This was the first time a biologically active peptide hormone had been synthesized in a lab, proving that laboratory-made peptides could replicate the function of naturally occurring ones.

Du Vigneaud received the Nobel Prize in Chemistry in 1955 for this achievement. His work opened the door for researchers to study peptide hormones without relying solely on animal tissue extraction — a principle that remains central to modern peptide research.

The 1960s: Allan Goldstein and the Discovery of Thymosin Peptides

In the early 1960s, immunologist Jacques Miller demonstrated that the thymus gland was essential for T-cell development — a finding that sent researchers hunting for the bioactive compounds the thymus was producing. Dr. Allan Goldstein and his team at the Albert Einstein College of Medicine took up this challenge.

By 1972, Goldstein’s team had successfully isolated thymosin fraction 5, a complex mixture of peptides extracted from calf thymus tissue. In 1981, they identified and fully sequenced thymosin beta-4 — the 43-amino-acid parent peptide from which TB-500 is derived. Initially studied for immune regulation, thymosin beta-4 was later recognized in the 1990s as a major actin-sequestering molecule, fundamentally reframing the peptide as a cytoskeletal regulator involved in tissue repair and cell migration.

1973: Loren Pickart Discovers GHK-Cu — The Copper Peptide

In 1973, biochemist Dr. Loren Pickart made an observation that would take decades to fully appreciate. While studying human aging, he noticed that blood plasma from young donors (ages 20–25) was significantly more effective at promoting liver cell protein synthesis than plasma from older donors (ages 60–80). Something in young blood was driving cellular vitality that disappeared with age.

After rigorous isolation work, Pickart identified the factor as a three-amino-acid peptide — glycine-histidine-lysine — naturally complexed with copper(II) ions. He named it GHK-Cu. Naturally present in human plasma, saliva, and urine, GHK-Cu concentrations decline substantially with age — a finding that has made it one of the most studied peptides in skin biology and regenerative research.

It was not until the late 1980s that copper peptides began appearing in commercial skincare formulations, but the research applications have expanded far beyond cosmetics into wound healing, hair biology, and tissue remodeling.

The 1970s–1980s: Growth Hormone Secretagogues and Epitalon

Two parallel research programs during this era would produce compounds still heavily studied today.

Growth Hormone Releasing Peptides

In the 1970s, pharmacologist Cyril Bowers discovered that small synthetic peptides based on enkephalin could stimulate growth hormone release from pituitary cells — without acting through opioid receptors. This unexpected finding launched the entire field of growth hormone secretagogues and led to the development of GHRP-6, the first widely studied GH-releasing peptide.

This line of research would eventually produce Ipamorelin in 1998, developed by Novo Nordisk. Ipamorelin became the first selective growth hormone secretagogue — capable of stimulating GH release without raising cortisol or prolactin, even at 200 times the effective dose. That selectivity profile made it a preferred research tool and a staple in modern peptide laboratories.

CJC-1295, a synthetic analog of growth hormone-releasing hormone (GHRH), emerged from a separate but related research track. When combined with Ipamorelin, these two peptides became one of the most commonly referenced pairings in growth hormone research literature.

Vladimir Khavinson and the Pineal Peptides

Meanwhile in the Soviet Union, gerontologist Vladimir Khavinson began a decades-long research program at what would become the St. Petersburg Institute of Bioregulation and Gerontology. Starting in the 1970s, Khavinson’s premise was that organs contain short peptide sequences that regulate gene expression in age-dependent, tissue-specific ways.

From pineal gland extracts (epithalamin), his team synthesized a simplified four-amino-acid analog — Ala-Glu-Asp-Gly — and named it Epitalon. Decades of subsequent research suggested it extended lifespan in animal models, restored melatonin rhythms in aging subjects, and activated telomerase in cultured human cells. The compound remains one of the most discussed peptides in longevity research.

The 1980s–1990s: Melanocortin Research and the Accidental Discovery of PT-141

Some of the most important peptide discoveries happen by accident. In the 1980s, researchers at the University of Arizona were developing Melanotan II — a synthetic melanocortin receptor agonist — primarily to study skin pigmentation. During clinical testing, participants reported an unexpected and consistent side effect: significantly increased sexual arousal.

This serendipitous finding shifted the research toward understanding melanocortin pathways in the central nervous system. From Melanotan II, researchers developed PT-141 (Bremelanotide) — a more selective cyclic peptide that retained the pro-sexual effects while reducing tanning activity. Described formally in the scientific literature in 2003 by Palatin Technologies, PT-141 became the first compound to demonstrate that sexual response could be modulated through central nervous system pathways rather than peripheral vascular mechanisms.

The 1990s: BPC-157 — A Peptide from Gastric Juice

In the early 1990s, Croatian scientist Dr. Predrag Sikiric and his colleagues at the University of Zagreb were studying the protective properties of human gastric juice. They observed that a specific protein in gastric secretions (Body Protection Compound) played a fundamental role in protecting the gastrointestinal lining, reducing inflammation, and promoting healing.

From this parent protein, Sikiric’s team isolated a 15-amino-acid fragment and named it BPC-157. The peptide was first synthesized in 1993 by R. Rucman, with the earliest published results appearing in 1999. What made BPC-157 stand out was the breadth of its studied effects — spanning gastrointestinal tissue, tendons, ligaments, muscle, bone, and nervous tissue across hundreds of published studies, predominantly from Sikiric’s laboratory in Zagreb.

BPC-157 remains one of the most widely researched peptides in the regenerative compound space, though discussion continues regarding the need for larger, multi-center human trials.

Researchers studying tissue recovery protocols often pair BPC-157 with TB-500, creating what the community calls the Wolverine Blend — named for the theoretical synergy between two different repair-pathway peptides.

2015: MOTS-c — The Mitochondrial Peptide That Rewrote the Textbooks

For decades, scientists believed mitochondrial DNA encoded only 13 proteins — all components of the electron transport chain. In 2015, Dr. Changhan David Lee and Dr. Pinchas Cohen at the University of Southern California proved that assumption wrong.

They discovered MOTS-c (Mitochondrial Open Reading Frame of the 12S rRNA-c), a 16-amino-acid peptide encoded by mitochondrial DNA that acts as a systemic hormone. Published in Cell Metabolism, their discovery revealed that mitochondria do not just generate energy — they produce signaling molecules that regulate whole-body metabolism.

MOTS-c is upregulated in response to exercise and has been characterized as an exercise mimetic — a compound that activates some of the same metabolic pathways as physical activity. This made it immediately relevant to metabolic research and aging studies.

2020s: The GLP-1 Revolution and triple-receptor research peptides

The most publicly visible peptide discovery story of the 2020s involves the incretin system. The foundational research traces back to an unlikely source: the saliva of the Gila monster lizard, from which exenatide (a GLP-1 receptor agonist) was first derived and eventually approved for type 2 diabetes treatment.

Building on this, Eli Lilly developed Tirzepatide — a dual GLP-1/GIP receptor agonist approved by the FDA in 2022. But the most aggressive next-generation compound is Retatrutide (LY3437943), a synthetic 39-amino-acid triple agonist that simultaneously activates GLP-1, GIP, and glucagon receptors.

Engineered from a GIP peptide backbone with non-coded amino acid residues and a fatty diacid side chain for extended half-life, Retatrutide represents the cutting edge of incretin peptide engineering. Phase 2 clinical trial data published in the New England Journal of Medicine showed up to 24% body weight reduction — making it the most potent weight-management compound in clinical development at the time of publication.

What 125 Years of Peptide Discovery Tells Researchers Today

A few patterns emerge when you look at this timeline as a whole.

First, many of the most significant peptides were discovered by accident or through adjacent research — PT-141 came from tanning studies, BPC-157 from gastrointestinal protection work, and GHK-Cu from aging blood plasma comparisons. The best discoveries often come from researchers paying attention to unexpected results.

Second, the gap between discovery and practical application is often decades. GHK-Cu was discovered in 1973 but did not appear in commercial formulations until the late 1980s. Thymosin beta-4 was sequenced in 1981 but was not recognized as a tissue repair molecule until the 1990s. Researchers working with these compounds today are building on foundations laid 30 to 50 years ago.

Third, the pace is accelerating. MOTS-c went from discovery to active research programs in under a decade. Retatrutide moved from preclinical publication to Phase 3 trials in roughly two years. Modern analytical tools, synthetic chemistry platforms, and computational modeling are compressing timelines that once stretched across generations.

For researchers sourcing compounds today, this history underscores why documentation matters. Every peptide carries the weight of the research program that produced it. Purity verification, proper identification, and published certificates of analysis are not bureaucratic overhead — they are the minimum standard that honors the scientific tradition these compounds came from.

All compounds referenced in this article are sold strictly for laboratory and research purposes. Prax Peptides does not condone or promote human consumption of research chemicals. All applicable research regulations and institutional guidelines must be followed.