Peptides aren't new - They've been around for decades

Peptides seem to be everywhere right now

They are being discussed in podcasts, gyms, research laboratories, longevity clinics and mainstream news. GLP-1 receptor agonists have become household names. Scientists are investigating peptide-based approaches across metabolism, cardiovascular disease, cancer, inflammation, neurological disease, mitochondrial biology and ageing. Even people who had never heard the word “peptide” a few years ago are suddenly encountering it regularly.

It creates the impression that we have stumbled across some completely new branch of science.

We haven't.

In fact, one of the most important medicines ever developed is built around peptide biology, and its story began more than a century ago.

Insulin.

Before insulin became available, a diagnosis of type 1 diabetes was devastating. Physicians could attempt to prolong life through extreme dietary restriction, but they could not replace what the body was missing. That changed dramatically following the isolation of insulin in the early 1920s and its first successful therapeutic use in 1922.

Suddenly, scientists had demonstrated something extraordinary. A biological messenger naturally produced by the body could be isolated, administered and used to profoundly alter human physiology.

Nobody was calling it peptide therapy.

Nobody was talking about biohacking or longevity.

They were simply trying to stop people from dying.

But insulin helped establish a principle that would eventually become fundamental to modern medicine: the molecules our bodies use to communicate with themselves can sometimes be harnessed therapeutically.

And the human body uses peptides to communicate constantly.

At their simplest, peptides are chains of amino acids. Proteins are also constructed from amino acids, but peptides are generally smaller. Their size and structure allow many of them to function as remarkably precise biological messengers.

Some act as hormones. Others participate in neurological signalling, immune function, appetite regulation, metabolism, growth and countless other physiological processes.

Your body was using peptides long before scientists gave them names.

Once researchers began identifying these biological messengers, an obvious problem emerged.

Discovering a peptide was one thing.

Making one was considerably harder.

Early peptide medicines often depended on extracting biological material from animals. Insulin itself was originally obtained from animal pancreases. If peptide science was ever going to expand, researchers needed a reliable way of building these molecules themselves.

By the middle of the twentieth century, that was beginning to happen.

In the 1950s, scientists successfully synthesised peptide hormones including oxytocin and vasopressin. It demonstrated that biologically active peptides could be constructed chemically rather than simply harvested from tissue.

Then, in 1963, American biochemist Robert Bruce Merrifield introduced a technique that would fundamentally change peptide chemistry: solid-phase peptide synthesis.

The concept was ingenious. Instead of repeatedly isolating and purifying a growing peptide after each chemical reaction, the developing chain could remain attached to a solid support while amino acids were added sequentially.

It made peptide construction faster, more systematic and increasingly scalable.

Scientists could now do more than reproduce molecules found in nature.

They could start changing them.

Swap one amino acid.

Shorten a sequence.

Extend another.

Alter the structure and see what happened.

Peptide biology was gradually becoming peptide engineering.

And while much of this work was developing in Western universities and pharmaceutical laboratories, another fascinating chapter of peptide research was unfolding behind the Iron Curtain.

The Soviet Union had a substantial scientific interest in biological regulation.

This included research into adaptation, stress, immunity, ageing and maintaining physiological function under demanding conditions. Peptides became one part of that much larger research effort.

There is a temptation when telling this story to turn it into something mysterious: secret Soviet anti-ageing compounds, cosmonaut drugs and hidden military programs.

Some of those stories have grown considerably in the retelling.

The documented research is interesting enough without needing the mythology.

By the latter half of the twentieth century, Soviet laboratories were actively studying peptide hormones, peptide chemistry and synthetic peptide analogues. Researchers worked with compounds including oxytocin, vasopressin, ACTH and somatostatin while also developing peptide preparations of their own.

One particular branch of this research would continue long after the Soviet Union itself disappeared.

During the 1970s, researchers including Vladimir Khavinson and Vyacheslav Morozov began investigating what became known as peptide bioregulators.

Their question was different from simply asking whether a peptide could replace a missing hormone.

They were interested in whether relatively short peptide sequences associated with particular tissues could participate in regulating the function of those tissues.

Research initially involved peptide preparations derived from organs including the thymus and pineal gland. This work eventually produced preparations such as Thymalin and Epithalamin, while later research increasingly investigated shorter synthetic peptide sequences.

The context matters.

Some of this work emerged from Soviet military medicine, where researchers were interested in maintaining physiological resilience and immune function under demanding conditions. Other work eventually became closely associated with Russian gerontology and the biology of ageing.

Khavinson and colleagues continued investigating these ideas for decades, eventually publishing studies examining thymic and pineal peptide preparations in older populations. One published program followed 266 older participants for six to eight years after treatment during the initial years of observation.

The researchers reported intriguing outcomes, including changes in physiological measures and mortality.

But this is where history and evidence need to be separated.

Much of the peptide-bioregulator literature came from a relatively concentrated network of Russian researchers and institutions. The findings have not always been independently reproduced through the kind of large, multicentre, randomised clinical trials that would be expected before making strong therapeutic claims today.

That does not mean the Soviet research should be dismissed.

Nor does it mean every conclusion drawn from it should simply be accepted.

It means we should recognise it for what it was: an early and unusually ambitious attempt to understand whether short peptides could act as biological regulators.

And importantly, researchers were asking those questions decades before the modern longevity industry existed.

That is one of the recurring themes throughout the history of peptide science.

The questions often arrived long before the technology required to answer them properly.

Because despite their biological potential, peptides had problems.

Lots of them.

The human body is extremely good at destroying peptides. Enzymes known as proteases break peptide bonds apart. Many naturally occurring peptides survive in circulation for only a short period of time.

The digestive system presents an even larger problem.

Put many peptides into the stomach and the body treats them exactly as it treats other chains of amino acids: something to be broken apart.

Cell membranes create another obstacle. Peptides are often larger and more polar than traditional small-molecule drugs, which can make entering cells difficult.

Manufacturing was historically difficult and expensive.

Storage could be challenging.

Delivery could be inconvenient.

A molecule could have fascinating biological activity in a laboratory and still make an absolutely terrible medicine.

For pharmaceutical developers, small molecules often looked much easier.

They could frequently be manufactured relatively cheaply, compressed into tablets, swallowed, absorbed and designed to remain stable for useful periods.

Peptides often required injection only to disappear from circulation relatively quickly.

The biology was exciting.

The pharmacology was a pain in the arse.

So researchers began trying to solve the problems rather than abandoning the molecules.

And gradually, they got better at it.

Solid-phase peptide synthesis improved dramatically. Purification improved. Analytical chemistry improved. Recombinant DNA technology opened entirely new manufacturing possibilities.

In 1982, recombinant human insulin became the first recombinant DNA-derived medicine approved by the US FDA.

Instead of relying on insulin extracted from animal pancreases, scientists could insert human genetic instructions into microorganisms and essentially turn living cells into biological manufacturing systems.

It was an extraordinary shift.

At the same time, peptide chemists became increasingly sophisticated at modifying the molecules themselves.

A naturally occurring peptide no longer had to be treated as the finished product.

It could be the starting point.

Individual amino acids could be substituted to alter receptor binding or enzymatic stability. Chemical groups could be attached to change how long a peptide remained in circulation. Structures could be modified to slow degradation. Delivery systems could be engineered around biological limitations.

Nature provided the message.

Scientists began editing the message.

That distinction is fundamental to understanding modern peptide medicine.

Many of today's peptide-based drugs are not simply identical copies of naturally occurring peptides. They are engineered relatives designed to preserve desirable biological activity while overcoming the weaknesses that made the natural molecule impractical as a medicine.

And nowhere is that story more obvious than with GLP-1.

Today, almost everybody has heard of Ozempic.

Far fewer people realise that the science behind it stretches back decades.

Glucagon-like peptide-1, or GLP-1, is a naturally occurring peptide hormone.

Among its physiological roles, it participates in glucose-dependent insulin secretion, glucagon regulation, gastrointestinal function and signalling related to appetite and food intake.

Researchers had been studying incretin biology long before GLP-1 drugs became global phenomena.

The problem was familiar.

Native GLP-1 is broken down extremely rapidly in the body.

Once again, nature had produced fascinating biology but an inconvenient medicine.

So scientists engineered around it.

The first GLP-1 receptor agonist reached clinical medicine in the mid-2000s. Further generations followed. Liraglutide arrived. Then semaglutide.

By modifying molecular structures and pharmacokinetics, researchers transformed signalling biology measured in minutes into medicines capable of acting for dramatically longer periods.

Then scientists pushed the idea further.

Why target only one signalling pathway?

Tirzepatide was engineered to activate both GIP and GLP-1 receptors.

Research then progressed toward compounds capable of simultaneously interacting with three metabolic receptor systems, including GLP-1, GIP and glucagon receptors.

A naturally occurring biological signalling system had become the foundation for increasingly sophisticated molecular engineering.

And the results changed more than medicine.

They changed public awareness.

For decades, peptide pharmacology had largely existed outside mainstream conversation.

People used peptide medicines without necessarily thinking of them as peptide medicines.

Then GLP-1 drugs exploded.

Suddenly peptide-based medicines were discussed by celebrities, journalists, doctors, athletes, politicians and millions of ordinary people.

Weight-loss pharmacology became dinner-table conversation.

People who had never opened a pharmacology paper were discussing receptors, appetite signalling and metabolic hormones.

Peptides had not suddenly arrived.

The public had finally noticed them.

And their rise into mainstream conversation happened at almost exactly the same time that peptide science itself was becoming dramatically more sophisticated.

Modern researchers possess tools that scientists working in the 1950s — or Soviet laboratories in the 1970s — could barely have imagined.

Mass spectrometry allows researchers to characterise molecules with extraordinary precision.

High-performance liquid chromatography allows complex mixtures to be separated and analysed.

Modern genetic sequencing can help identify new biological signals and their receptors.

High-throughput screening allows researchers to evaluate enormous numbers of molecular candidates.

Computational modelling can help predict how molecules may interact with biological targets.

Machine learning and artificial intelligence are increasingly being incorporated into peptide discovery and molecular design.

Manufacturing has become more sophisticated.

Purification has become more precise.

Our ability to modify peptide stability, receptor selectivity and pharmacokinetics has improved enormously.

Even one of peptide medicine's oldest problems — oral delivery — is beginning to be overcome in selected circumstances.

Oral semaglutide demonstrated that, with specialised formulation technology, even a peptide-based GLP-1 medicine could achieve gastrointestinal absorption.

This changes the fundamental question researchers can ask.

For much of peptide history, scientists were asking:

What peptides does biology give us, and what do they do?

Increasingly, modern researchers can ask:

What could we design a peptide to do?

That is a completely different research environment.

And it helps explain why the modern peptide landscape has expanded far beyond metabolic medicine.

Researchers are investigating peptides and peptide-inspired compounds across oncology, cardiovascular medicine, inflammatory disease, neurological disorders, antimicrobial research, tissue repair, immune signalling and mitochondrial biology.

Some peptides are being investigated because they activate a receptor.

Others block one.

Some imitate naturally occurring hormones.

Some influence signalling pathways.

Some are being investigated as targeting molecules capable of carrying another therapeutic payload toward particular cells.

And others have led researchers into areas of biology we barely understood when peptide medicine began.

Mitochondrial research provides a fascinating example.

MOTS-c is a mitochondrial-derived peptide encoded within mitochondrial genetic material and has been studied for its relationship with metabolic stress signalling.

Elamipretide, or SS-31, was developed around mitochondrial membrane biology and eventually progressed from experimental research to an FDA-approved application for the rare mitochondrial disorder Barth syndrome in 2025.

These molecules are separated by enormous differences in evidence and clinical development, but they demonstrate how far the field has moved.

Scientists are no longer simply asking whether we can replace a missing peptide hormone.

They're asking whether peptide-based molecules can influence extremely specific pieces of cellular machinery.

That is where today's research becomes particularly exciting.

But it is also where we need to be careful.

The fact that peptide medicine has existed for more than a century does not mean every peptide discussed today is an established medicine.

Insulin is a peptide.

Semaglutide is peptide-based.

Oxytocin is a peptide.

That tells us absolutely nothing about whether an unrelated experimental peptide is safe or effective.

Every molecule has to earn its own evidence.

Some compounds have decades of clinical data and regulatory approval.

Others are currently moving through human clinical trials.

Some have only small early human studies.

Others remain predominantly within animal research.

Some have been studied only in cells.

And some compounds that have become extremely popular online have considerably less evidence than their reputation might suggest.

This is one of the most important things to understand about the modern peptide world.

“Peptide” describes a type of molecule. It is not a stamp of clinical validation.

The history tells us peptides can become extraordinarily important medicines.

It doesn't tell us which experimental peptides will become the next ones.

That is what research is trying to determine.

A compound might demonstrate an elegant mechanism in cultured cells and fail completely in an animal.

Something can work beautifully in mice and fail in humans.

A molecule may change exactly the biomarker researchers hoped it would change while producing no meaningful clinical benefit.

A promising compound can encounter unexpected toxicity.

Manufacturing problems can kill development.

Delivery problems can make otherwise excellent biology practically useless.

Or occasionally, after years or even decades of research, something extraordinary emerges.

GLP-1 medicine is perhaps the perfect modern example.

The medicines people recognise today did not appear overnight.

They emerged from decades of research into gastrointestinal hormones, glucose metabolism, receptors, enzymatic degradation, medicinal chemistry and drug delivery.

Thousands of individual scientific discoveries eventually converged into medicines capable of producing effects that would once have seemed extraordinarily difficult to achieve pharmacologically.

That is why today's experimental research should neither be dismissed nor treated as established fact.

Research sits in the space between those two extremes.

It is the process through which we find out.

And perhaps that is the most useful way to understand why peptides suddenly seem so important.

The molecules themselves aren't new.

Our understanding of them is.

Insulin showed more than a century ago that peptide biology could be harnessed to save human lives.

Mid-century chemists demonstrated that peptide hormones could be synthesised.

Merrifield transformed the way peptides could be constructed.

Soviet researchers spent decades exploring whether short peptides might function as biological regulators.

Recombinant biotechnology transformed manufacturing.

Modern analytical chemistry gave scientists unprecedented ability to determine molecular identity and purity.

Medicinal chemistry taught researchers how to modify peptides so they lasted longer and behaved differently.

GLP-1 medicines demonstrated to the entire world just how powerful sophisticated peptide engineering could become.

And now computational biology, advanced analytical technologies and artificial intelligence are opening another chapter.

Some of the research happening today will go nowhere.

Some will teach us something useful about biology without ever producing a medicine.

Some compounds will fail when they finally reach human trials.

And somewhere among the enormous amount of work happening around the world, there may be molecules that eventually change medicine again.

We don't know which ones.

That's the point.

Peptides haven't suddenly appeared because social media discovered them.

They have been part of medicine for more than a century and part of experimental biological research for generations.

What we are witnessing today isn't the beginning of peptide science.

It is what happens when a very old biological language meets increasingly powerful modern technology.

The peptides were already here.

The biology was already here.

We're simply becoming much better at learning how to speak the language.

References & Further Reading

1. Lau JL, Dunn MK. Therapeutic peptides: Historical perspectives, current development trends, and future directions. Bioorganic & Medicinal Chemistry. 2018;26(10):2700–2707.

2. Wang L, Wang N, Zhang W, et al. Therapeutic peptides: current applications and future directions. Signal Transduction and Targeted Therapy. 2022;7:48.

3. Merrifield RB. Solid phase peptide synthesis. I. The synthesis of a tetrapeptide. Journal of the American Chemical Society. 1963;85:2149–2154.

4. Khavinson VK. Peptides and Ageing. Neuro Endocrinology Letters. 2002;23 Suppl 3:11–144. PMID: 12374906.

5. Khavinson VK, Morozov VG. Peptides of pineal gland and thymus prolong human life. Neuro Endocrinology Letters. 2003;24(3–4):233–240. PMID: 14523363.

6. Furgal SM, Degtiarev AA, Seryĭ SV, Khavinson VK. Research examining the synthetic thymic peptide Thymogen in a military population. Voenno-Meditsinskii Zhurnal. 1993. PMID: 8498021.

7. Drucker DJ. GLP-1-based therapies for diabetes, obesity and beyond. Nature Reviews Drug Discovery. 2025;24:631–650.

8. Holst JJ. GLP-1 physiology in obesity and development of incretin-based drugs for chronic weight management. Nature Metabolism. 2024;6:1866–1885.

9. Kruse T, Østergaard S. Redefining peptide therapeutics with semaglutide. Nature Chemistry. 2024;16:296.

10. Reynolds JC, Lai RW, Woodhead JST, et al. MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis. Nature Communications. 2021;12:470.

11. Roshanravan B, Liu SZ, Ali AS, et al. In vivo mitochondrial ATP production is improved in older adult skeletal muscle after a single dose of elamipretide in a randomized trial. PLOS ONE. 2021;16(7):e0253849.

12. United States Food and Drug Administration. FDA Grants Accelerated Approval to First Treatment for Barth Syndrome. September 19, 2025.

Research Disclaimer

This article is provided for educational and research purposes only. Discussion of peptides, experimental compounds and biological pathways does not constitute medical advice or a recommendation for human use. Peptides discussed in research literature exist at widely different stages of development. Some are approved medicines for specific indications, while others remain investigational or have limited or no controlled human clinical evidence. Findings from cellular and animal research should not be assumed to translate directly to humans, and the established use of one peptide medicine does not establish the safety or effectiveness of unrelated experimental compounds.