Peptides may have predated ribosomes—the cell's protein factory

RNA may have allowed life to exist before DNA

The emergence of living organisms from non-living matter—abiogenesis—requires both a molecule that encodes genetic information and proteins that perform biochemical processes. However, because DNA and protein depend on one another, some biologists theorize that RNA, which can both store information and perform functions, preceded both and originated life.

Peptide research dates back to the late 1800s

Peptide science dates back to the late 1800s with some early peptide synthesis work, but peptides took off in the medical sphere after surgeon Frederick Banting and his colleague's isolation of insulin from dog pancreases in 1921.

The word peptide comes from Greek

Originating from the Greek term "peptos," which means digestible, peptide as a word refers to two or more amino acids. (Some users may encounter a paywall.)

Watch how proteins are created from DNA

When a DNA sequence—a gene—is activated, a copy of the activated portion is created in the form of RNA, a single-stranded version of DNA, in a process known as transcription. This RNA, called messenger RNA, leaves the nucleus and travels to a ribosome, a structure within a cell, which uses it to build a chain of organic compounds that fold into a protein.

China is producing many peptides or peptide components sold in the US.

Early peptide research focused on isolating the substances from animal tissue

In the first half of the 20th century, peptides including insulin and adrenocorticotropic hormone were isolated from animals to provide life-saving medicines. ACTH was isolated from the pituitary glands of cows and pigs and insulin was isolated from the pancreas of dogs and cows.

Peptides like GLP-1 account for 31 of 370 new drugs approved by the US FDA between 2016 and 2023.

Cells translate genetic information into proteins using RNA messengers

Genes are segments of DNA, each composed of a sequence of nitrogenous bases. Within the nucleus, these sequences are copied into a single strand of ribonucleic acid during transcription. This strand leaves the nucleus and is translated by ribosomes into a chain of amino acids that folds into a functional protein.

The US FDA defines peptides as being 40 amino acids or less.

DNA's four-letter blueprint makes the variety of all living things possible

The proteins responsible for cellular functions and an organism's traits are built outside of a cell's nucleus from RNA—single-stranded molecules created by reading the information in DNA. DNA's double-stranded structure makes it more stable and allows RNA to be made from either of its complementary strands.

Some organelles are believed to have once been independent cells

Mitochondria and chloroplasts, which are both responsible for energy production in cells, have DNA distinct from that of their host cells and are surrounded by cellular membranes resembling those of bacteria. Through symbiogenesis, these and other specialized structures were absorbed into larger cells, forming the modern-day biological units.

Abiogenesis explains how Earth's natural processes could have formed organic matter

The theory details how chemical interactions in hydrothermal vents and shallow ponds billions of years ago could have created lipids, proteins, and RNA. As these interactions involve water, life is thought to have started in oceans.

Learn how chloroplasts—the photosynthesis factories—may have once been independent cells

Possessing DNA of their own that differs from that of their host cell and surrounded by cellular membranes like those observed in bacteria, chloroplasts are believed to have evolved from a cyanobacterial cell. The endosymbiotic theory explains that these organelles were absorbed into larger cells, leading to the photosynthetic cells seen today.

Read a deep dive on the 'all-purpose healing' peptide BPC-157.

Biotech is trying to boost drug production efficiency—using chicken eggs

A company called Neion Bio is genetically engineering birds in a bid to produce medical compounds, a herculean task that scientists have struggled with for decades. The US FDA has approved only one chicken-derived drug in the past—an expensive treatment for a rare liver disorder. (Some users may encounter a paywall.)

Evidence suggests the first cells on Earth were bacteria

About 4 billion years ago, these single-celled organisms harvested carbon dioxide and sunlight to produce their own food and oxygen, setting the stage for the evolution of oxygen-breathing life forms. Archaeabacteria, which thrive on inorganic molecules in extreme habitats on Earth today, were also among the earliest organisms.

Cells modify their internal spacing to improve biochemical reaction efficiencies

Studies involving microscopy and genetic engineering tools in yeast and human cells show ribosomes act as crowding agents—much like packing peanuts—and their concentrations are actively tuned to alter the rate of cellular functions. However, these concentrations and cell crowding levels vary across different tissues and cell types.

In 2026, researchers at the University of Minnesota created the world's first synthetic cell—a cell made from non-living chemical components—that can eat, grow, divide, and compete with other cells for resources.

Bacteria helped scientists realize that DNA was the hereditary molecule, not proteins

Until the mid-1900s, most scientists believed genes were made of proteins, which were known to act as enzymes, hormones, and other chemicals that mediated an organism's traits. The Avery-MacLeod-McCarty and that benign bacteria could be made lethal, where the inherited factor that caused bacterial transformation contained DNA.

The US FDA issued a 2025 warning about BPC-157 and other popular peptides that are marketed for various regenerative properties.

Before discovering cells, life was believed to emerge suddenly from inorganic matter

Popularized by Aristotle in the 4th century BCE, spontaneous generation was used to explain phenomena like mice appearing in seemingly sealed grain storage. The invention of the compound microscope in the late 16th century led to the identification of cells as the basic unit of life, but it was not until 1855 that their origin from preexisting cells was established.

Scientists have created a cell from scratch—called a SpudCell—proof-of-concept work that a lab-made cell can feed, grow, and replicate like a natural cell.

Two festival-goers were hospitalized after receiving trendy peptide injections, raising safety questions that may extend beyond the event.

Where do genes come from?

There are many more genes on Earth today than when microbial life first spawned on the planet about four billion years ago. Many of these newer genes grew from genetic mutations, misprints that slowly drift from the original blueprint via cellular division. If these mutations drift far enough, they can establish a new family of genes, though this process can take well over a million years.

Hormone and peptide compounds imported from China soared in 2025

US customs data indicates that these imports doubled to $328M in the first three quarters of 2025, from $164M in the same period of 2024. The imports include GLPs, among other products. (Some users may experience a paywall.)

Only 2% of human DNA codes for proteins

The entire human genome contains about 20,000 protein-coding genes, with the rest having initially been categorized as "junk" DNA. However, research since 2003 suggests that this "dark genome" regulates how protein-coding genes are expressed in response to environmental factors encountered by cells.

Recombinant DNA technology turns microorganisms into protein factories

Genes for molecules such as insulin can be inserted into loops of bacterial DNA called plasmids and reinserted into bacteria. Once placed in fermentation tanks, these bacteria use the gene to produce these molecules, which are then harvested and purified for eventual use.

Spontaneous metabolism may give clues to origins of life

Read this article to learn more about the discovery that suggests that metabolism could have begun spontaneously on our planet—and why it means that scientists may need to rethink how we define life’s origins. A team of researchers at the...

Peptides like BPC-157 are marketed based largely on animal studies, not human research

BPC-157, which purportedly helps with tissue repair and muscle growth, can cause concerning side effects, including pain and swelling. TB-500, another experimental peptide, is marketed for wound healing, but it hasn't undergone any clinical human trials, and high levels of this peptide have been linked to tumor growth. (Some users may encounter a paywall.)

Panspermia, the theory that cellular life came from a different planet

One of the most profound mysteries of human life on earth is the presence of living cells: organic, self-organizing, reproducing creatures with a drive to survive within given set conditions. Traditional theories posit life came from divine...

Critical organic molecules have been found on an asteroid

NASA's OSIRIS-REx mission returned samples containing amino acids and nucleobases from asteroid Bennu. Without Bennu having been destroyed—as is common for asteroids that enter Earth's atmosphere—its samples serve as a time capsule of the solar system's early chemistry.

Peptide TB-500, promoted for regenerative healing, is not FDA approved

Watch a board-certified sports medicine therapist detail his thinking about this synthetic peptide; he says it's "promising but unproven." He notes that this product is designed to mimic the natural protein thymosin beta-4, found in human and animal tissues, which promotes wound healing. TB-500 is classified as a research peptide for recovery, meaning it's not approved for human use and has not yet undergone rigorous human trials on its safety and efficacy.

Snake venoms are repurposed proteins responsible for other bodily functions

Just as saliva aids digestion in humans, proteins responsible for bioactivities such as digestion and blood clotting were eventually secreted in the glands and fangs of snakes across evolutionary history. Organisms that could not withstand the effects of these molecules (e.g., excessive bloodstream clotting) became ideal prey for snakes.

The World Anti-Doping Agency has banned many peptides

The global body has an entire section dedicated to banned peptide hormones, including ones that may stimulate growth hormones and testosterone. BPC-157 was added to the list in 2022.

The flavor of food can be enhanced by combining chemicals known to trigger umami taste receptors with nucleotides—building blocks of DNA and RNA—triggering an effect called umami synergy.

mRNA vaccines teach the immune system how to respond to a threat, using a molecule called messenger RNA.

Diabetes drug GLP-1 is a peptide (that's what the 'P' is for).

Genetic analysis indicates that every organism on Earth evolved from a single cell

LUCA—the last universal common ancestor—lived about 4.2 billion years ago and likely obtained energy through the conversion of carbon dioxide and hydrogen gas consumed from atmospheric gases at the ocean's surface or hydrothermal vents—openings on the seafloor where fluid warmed and enriched with minerals by Earth's interior is expelled.

View a collection of historical documents about molecular biology's history

The collection features materials related to those involved in the discovery of DNA and provides historical context for the discoveries of RNA, various viruses, and important bioproteins. The items include photographs, business correspondence, manuscripts, and scientific instruments.

How humans evolved from single-cell organisms

Humans have had a long history. 3.8 billion years in the making, to be precise. From the primordial puddle to the modern day, here's how humans have evolved from the first life.

Animals' stomach lining produces cheese

Cheesemaking would be impossible without rennet, the enzyme that separates milk’s liquid and solid components. Rennet occurs naturally in the stomach lining of young goats, cows, and lambs to help them digest milk, a process that also allows cheesemakers to use it to make curds. Now we have plant-based rennet that comes from thistles, artichokes, and other similar plants.

Computational and biological systems share fundamental principles, like randomness

Proposed by Alan Turing and John von Neumann, the concept originates from how DNA and computers run by executing encoded instructions in parallel. The advent of AI and the temperature parameter has seen neural networks mimic the randomness of protein encoding.

The invention of cheese likely came from a fruit fly landing in a pail of fermenting milk

The chance encounter around 5,500 years ago laid the groundwork for cultured milk products like yogurt and cheese. Over time, microbes evolved in tandem with goats, sheep, and wheat to give us the wide variety of cheeses that we enjoy today.

The history of the gene: an interactive timeline

Humans didn’t need modern technology to figure out that kids tend to look like their parents. But what did humans believe about genetics before we knew about DNA or cells in general? Explore this interactive timeline to see how philosophers and scientists throughout the ages tried to explain how traits are passed from generation to generation.

Tardigrades’ intrinsically disordered proteins may help preserve biological matter

Researchers have attempted to create more drought-resistant crops by introducing proteins that help protect tardigrades in their dehydrated tun state. The proteins’ ability to stabilize molecular degradation may allow scientists to develop refrigeration-free storage for vaccines, insulin, and blood.

Synthetic biology transforms cells into custom DNA foundries

At companies like Ginkgo Bioworks, researchers are reprogramming cells to act as workshops that can create custom molecules, such as medicines and fertilizers, by stitching together DNA sequences—often in novel combinations—before inserting them into an organism's genome.

See the first dog ever treated with insulin—a peptide

Frederick Banting and his graduate student Charles Best were the first to isolate the peptide insulin from dogs. They induced diabetes in the animals and then treated them with this peptide.

Because it is observed in organisms that are not closely related, biofluorescence is thought to have emerged independently many times in nature—over 100 in fish alone.

The messy story of humanity's genealogical past

For decades, scientists viewed the human fossil record and concluded Neanderthals, an early hominin, came before homo sapiens, or modern humans. The story became more complicated as technology advanced and ancient DNA samples were analyzed. This video breaks down the evidence, concluding the development of humanity was a lot messier than previously believed.

The evolution of the human diet

Could eating like our ancestors make us healthier? One estimate suggests prehistoric hunter-gatherer communities obtained 75% of their calories from meat and fish.