How old are peptides, really?

The question has three different answers

Peptides split into three different ages. As a branch of chemistry they date to the turn of the twentieth century. As medicine they begin with insulin, which reached its first patient in January 1922. As the wellness category being advertised to you today, most of it is far younger than that.

"How long have peptides been around" sounds like it has one answer, and the reason different pages give you different numbers is that it does not. A peptide is a category, not a product. The word means a short chain of amino acids (the small building blocks your body links together to make proteins), and that description covers insulin, the collagen in a supplement tub, and a powder sold as research material on a website, equally well.

So three clocks are running at once. There is the chemistry, which is the oldest. There is peptide medicine, which begins with a single patient in a Toronto hospital. And there is the wellness category, the one most people meet through an advertisement or a short video, which is much the youngest of the three and is routinely described using the age of the other two.

That last move is where the confusion comes from, and it is worth naming before the history starts. "Peptides have been used safely for a hundred years" is a true sentence about insulin. It is not a statement about a vial someone is selling you, and most of this article is about how to tell those two sentences apart.

Peptide chemistry: the first paper is from 1901

Peptide chemistry is conventionally dated to 1901. Emil Fischer, working to establish what proteins are made of, published the first paper on the subject with a colleague that year. His model was that these molecules are chains of amino acids joined end to end by a repeating bond, which is still the definition in use.

The chemistry came first, and it has a date you can point at. Emil Fischer set out to work out the chemical nature of peptides and proteins, and in 1901 he and a colleague published the first paper on the subject [1]. The model that came out of that work is the one still taught: these molecules are chains, built from amino acids joined end to end by a repeating link called a peptide bond. Count forward from that paper and the field turns 125 in 2026, though that round number is a convention rather than a birthday, as the next paragraph shows.

Fischer did not work alone or from nothing. A survey of the field traces peptide chemistry from Theodor Curtius through Fischer and on to Bruce Merrifield [2], which is the arc worth holding onto: somebody worked out how to join two amino acids, somebody worked out what the resulting chains were, and somebody else, much later, worked out how to build them to order.

What that first era could not do was make anything useful in quantity. Building a chain by hand meant shielding every reactive group on the molecule, attaching one amino acid, then unpicking the shielding and starting over, and a little more product was lost at every step. For roughly sixty years, peptides were far easier to study than to manufacture, and a peptide you could not manufacture was not going to become a medicine.

Peptide medicine began with one patient in 1922

Peptide medicine starts in January 1922 in Toronto. The first insulin injection into Leonard Thompson failed, and a purer extract prepared by James Collip worked on 23 January. His blood glucose returned to normal and he lived thirteen more years. Insulin is a peptide hormone.

Peptide medicine has an almost equally sharp date, and getting to it did not go smoothly. Frederick Banting and his student and assistant Charles Best isolated insulin [3]. In January 1922 it was tried on a patient at Toronto General Hospital, the first injection failed, and the programme was salvaged by the biochemist James Collip, who prepared a more purified extract [14]. A second, successful injection was then administered to fourteen-year-old Leonard Thompson [14]. Insulin reached Thompson successfully on 23 January 1922 [3]. His glycosuria and ketonuria disappeared, his blood glucose returned to normal, he received daily injections, and he lived thirteen more years [3].

Insulin is a peptide hormone, and the surveys of this field date peptide therapeutics from its arrival rather than from anything earlier, which makes 1922 the honest starting line for the "peptides have been used for a century" claim. A survey of peptide drug discovery frames it the same way: since the introduction of insulin almost a century ago, more than 80 peptide drugs have reached the market, covering diabetes, cancer, osteoporosis, multiple sclerosis, HIV infection and chronic pain [6].

A second survey of the same landscape counts over 60 peptide drugs approved in the United States and other major markets, with over 150 peptides in active development [7]. The two counts differ because they were taken in different years and count different markets, and that is a useful thing to notice early: even the careful sources disagree about the size of this field, which is reason enough to distrust any page that hands you one confident figure.

This is the genuinely settled part of the history. Approved peptide medicines have been prescribed, monitored and written up for decades, and the evidence behind them is the ordinary evidence of pharmacology. It is also the part with almost nothing to do with the peptides being marketed online, which is what the rest of this article is about.

The invention that made all the others possible

Solid-phase peptide synthesis, developed by Robert Bruce Merrifield, anchored the growing chain to an insoluble bead so leftover reagents could be washed away between steps. It turned peptide synthesis from a specialist ordeal into something routine and automatable, and it won the 1984 Nobel Prize in Chemistry.

The single event that explains why peptides are everywhere now is technical rather than medical. Robert Bruce Merrifield proposed building a peptide while it stayed anchored to an insoluble support, so that after each step the leftover reagents could simply be washed off the bead rather than separated out by hand. The method is called solid-phase peptide synthesis, and a historical assessment of his career lists what he had to overcome to establish it: reducing the concept to practice, overcoming the resistance of synthetic chemists to the novel approach, and establishing that a biochemist had the scientific credentials to propose a revolution in chemical synthesis [4].

That resistance deserves a sentence, because it is the opposite of how this history usually gets told. The method that made modern peptide drugs possible was not welcomed on arrival; it had to argue its way in. It won the argument comprehensively. The Nobel Prize in Chemistry was awarded to Merrifield "for his development of methodology for chemical synthesis on a solid matrix" [5].

Everything downstream depends on that bead. Automated synthesisers, the milligram-scale vials sold as research compounds, and the industrial routes behind many approved peptide drugs are all descendants of it. It is also the reason a compound can exist as a purchasable powder long before anybody has established what it does in a person, which is the tension the rest of this article is built around.

The peptides in your feed are much younger than the field

Most peptides marketed today are decades younger than peptide chemistry itself. GHK, the copper-binding tripeptide used in skincare, was discovered in 1973. Exendin-4, the source of one branch of the GLP-1 drugs, was found in lizard venom. BPC-157 was isolated from human gastric juice. None of them inherits the record insulin has.

Ask the question about a specific compound and the answer changes completely. GHK, the copper-binding tripeptide sold in skincare as GHK-Cu, was discovered in 1973 as an activity in human albumin that caused old human liver tissue to synthesise proteins like younger tissue [8]. That is around fifty years, not a hundred and twenty-five, and it is fifty years of a largely laboratory literature rather than fifty years of clinical use.

Exendin-4 has a stranger origin than most people expect. It is a 39-amino-acid peptide discovered in the venom of Heloderma suspectum, the Gila monster, and it acts as a full agonist at the GLP-1 receptor; it resists the enzyme that clears the body's own GLP-1 and so has a much longer half-life [9]. That matters for dating the class, because GLP-1 receptor agonists are based on either the human GLP-1 sequence or the exendin-4 sequence [13]. One branch of this drug class came out of a lizard [9]. The other was built from the human GLP-1 sequence, a hormone people already make [13]. So there is no single origin date to quote for the class as a whole.

BPC-157 is younger still. It is a pentadecapeptide (a fifteen-unit chain) isolated from human gastric juice, and its published record is dominated by preclinical models of tissue injury, inflammatory bowel disease and central nervous system conditions [10]. It is also, right now, offered for sale on a great many websites [10].

Line those three up and the pattern is hard to miss. Peptides do not share an age. They share a chemical description, in roughly the way that "pill" describes aspirin and an unapproved supplement equally well, and nobody would offer aspirin's safety record as a reference for the supplement.

The age of a molecule is not the age of its evidence

How long a molecule has existed tells you almost nothing about how well it has been tested. BPC-157 has a large published record and is still approved by no regulator, because its clinical evidence in humans remains too thin to carry one. The pivotal weight-loss trials behind semaglutide and tirzepatide are far younger and far stronger.

Here is the part that actually matters, and the reason a history article belongs on a site about evidence. Age is not evidence. A compound can sit in the literature for decades and still have almost nothing said about it that would satisfy a regulator, because the studies that got run were the cheap ones.

BPC-157 is the clearest case. Its effects have been reported across a range of preclinical models, and a review of the literature and the patent filings states the position plainly: it has not been approved for use in standard medicine by the FDA and other global regulatory authorities, due to the absence of sufficient and comprehensive clinical studies confirming its health benefits in humans [10]. Decades of publication, and the human question is still open.

Now the contrast. The trial that established once-weekly semaglutide as a weight-management treatment enrolled 1961 adults and ran for 68 weeks, reporting a mean body-weight change of -14.9% against -2.4% on placebo [11]. The equivalent tirzepatide trial assigned 2539 adults across 72 weeks, with mean weight change reaching -20.9% in the highest dose arm against -3.1% on placebo [12]. Those are recent studies of recent molecules, and the weight of the evidence runs in the opposite direction to the age of the compound.

So the useful question is never "how long has this been around". It is "how long has this been tested in people, by whom, and with what result". For most compounds in this space those two questions have completely different answers, and the gap between them is where a great deal of the marketing lives.

How to date any peptide you are looking at

Three questions date a peptide honestly: when the molecule was first described, when human trials began and how large they were, and whether a regulator has approved it for anything. A compound can score well on the first and badly on the other two, and that combination is the one most often sold as heritage.

You can run this yourself in a few minutes, and it is a better use of the time than hunting for a single number.

When was the molecule first described? This is the date sellers quote, and it is the least informative of the three. It tells you when somebody found the thing, not what anybody later found out about it.

When did human studies begin, and how large were they? Look the compound up on a clinical-trials registry or on PubMed and read the participant counts. The distance between a study of a few dozen people and one of a few thousand is not a detail, it is the distance between a signal and an answer.

Has a regulator approved it, and for what? Approval is a coarse signal but a hard one. More than 80 peptide drugs have reached the market [6], so the bar is plainly clearable, and a compound that has been around for decades without clearing it is telling you something worth hearing.

Applied to the compounds above: insulin is old, heavily trialled and approved everywhere. Semaglutide is young, heavily trialled and approved. BPC-157 has a long publication record, thin human evidence, and approval from no regulator [10]. One of those three profiles is defensible on age alone, and it is not the one you will see quoted in an advertisement.

That is the whole trick. Peptides are not one thing with one age, and the century-long history behind the word is real, genuinely impressive, and mostly irrelevant to whatever is in the vial in front of you.