From insulin to the peptide boom

In the summer of 1921, in a hot Toronto laboratory, Frederick Banting and Charles Best extracted a substance from dogs’ pancreases that could lower blood sugar. By January 1922 a refined version, purified by James Collip, was injected into a fourteen-year-old boy named Leonard Thompson who was dying of type 1 diabetes. His blood sugar fell. He lived. On wards full of children in diabetic comas, doctors went bed to bed with the new extract; the story goes that some were waking before the team had finished the round.

The substance was insulin — the first peptide hormone ever isolated and used to treat disease. The discoverers sold the patent to the University of Toronto for one dollar. Insulin was not just a drug; it was the proof of a then-radical idea — that the body runs on chemical messengers, and that if you can supply a missing one, you can rewrite a death sentence.

For sixty years, insulin came from animals — extracted from the pancreases of millions of cattle and pigs. Then in 1982 came recombinant human insulin: the gene for human insulin inserted into bacteria, which then brewed the hormone in stainless-steel tanks. It was the first medicine ever made by recombinant DNA — the moment peptide hormones became something you could manufacture to spec rather than harvest.

That shift mattered enormously. A hormone you can synthesize is a hormone you can redesign — swap an amino acid, add a chain, change how long it lasts. Every modern peptide drug descends from that capability.

While diabetes care matured, the same logic was quietly building another field. Reproductive medicine runs on the gonadotropins — the pituitary peptides LH and FSH — and on GnRH, the pulse generator above them.

The first fertility drugs were peptide hormones purified from human urine — gonadotropins collected, famously, from postmenopausal women by the literal barrel. They made ovarian stimulation possible, and in 1978 the first child was born through in-vitro fertilization. Later came recombinant FSH and the GnRH analogs — agonists and antagonists — that let clinicians switch the reproductive axis off and on at will. An entire branch of medicine, built on tuning a handful of peptides.

Diabetes care kept advancing, and somewhere along the way the strategy changed. The first century was about replacement — give back the insulin a body could not make. The next idea was subtler: instead of replacing a missing hormone, amplify a working one.

The breakthrough came from an unlikely place. In the 1990s a researcher studying Gila monster venom found a peptide, exendin-4, that activated the human GLP-1 receptor but — unlike the body’s own GLP-1 — resisted rapid breakdown. Approved in 2005, it was the first of the incretin drugs: not a replacement hormone, but a re-engineered signal. Acylation — bolting a fatty-acid chain onto the peptide so it clings to albumin — then stretched the two-minute half-life of native GLP-1 into the week-long action of semaglutide. (For the receptor-level story, see how GLP-1 actually works.)

And then the molecules that had spent a century in clinics walked into the culture. The GLP-1 drugs — semaglutide, tirzepatide and their successors — became a genuine phenomenon: a weight-loss story big enough to reshape food companies’ forecasts, fill talk-show segments, and trigger global supply shortages. For the first time, a peptide hormone was a household word.

In their wake came a second, scrappier wave. A whole online culture of research peptides — compounds like BPC-157 and TB-500 — moved from obscure forums into mainstream wellness and biohacking, promoted for recovery, longevity, and performance. By 2026, “peptides” had become a lifestyle category, sold and discussed with a confidence that often ran far ahead of the evidence.

That is the whole job, for a reader in 2026: separating the molecule from the marketing. It is why every entry in this catalog carries an honest evidence badge — Established for the insulin-grade science, Preclinical or Limited for the compounds whose claims outrun their data — and why the biology comes before the benefits. The history is genuinely miraculous. The trick is not to let the hype borrow its credibility.