Peptides are defined as short chains of amino acids—the building blocks of proteins. They act as hormones, neurotransmitters, and signaling molecules in the human body, circulating in the blood and binding to receptors on targeted organs and tissues. They may also be synthetically produced or extracted from animal sources.
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The US Food and Drug Administration regulates these short strings of amino acids as drugs and approves them for commercial use. These products may be produced naturally or synthesized via medicinal chemistry for therapeutic use.
Glucagon-like peptide-1, or GLP-1, is one of the most well-known peptides in common use. In 2024, 26.5% of all adults with diagnosed diabetes used the substance. GLP-1 was particularly popular among people with diabetes aged 50-64, followed by younger adults and then seniors aged 65+.
Among the approved peptide-based drugs is the first-ever treatment for Rett syndrome, a rare inherited neurologic disorder that leads to a progressive loss of motor skills and language. Peptides are particularly attractive for multiple reasons, including their ability to selectively bind to cellular receptors to either activate or inhibit their function.
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.
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.
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.)
In January 1922, the 14-year-old was the first person to receive an insulin injection to treat diabetes, just months after insulin was isolated in dogs and used to treat their induced diabetes. Thompson had an allergic response to an apparent impurity in the injection, but his second dose, 12 days later, was a success.
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.
BPC-157, which mimics a naturally occurring gut peptide involved in soft tissue repair, has been marketed for various regenerative properties. But the FDA warned in July 2025 that it doesn't have enough data to assess its safety in humans and that such products may also pose risks related to contamination.
Investigative journalism shop PropPublica wrote about two people who became extremely ill following anti-aging peptide injections. Authorities were examining whether the individuals were sickened by an infection, contamination related to the injections, or an issue with the medication itself, according to documents obtained by the journalists at ProPublica.
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