What are peptides?
Peptides are short chains of amino acids that combine to form proteins. The body naturally produces peptides, which act as chemical messengers that help cells communicate and regulate important processes. Peptides play a role in growth, metabolism, healing and hormone activity.
Peptides are also found naturally in foods and can be manufactured for medical use. In fact, insulin is the first peptide produced in a laboratory for therapeutic use. It’s been used for decades to treat type 1 and 2 diabetes.
How are peptides different from proteins?
Peptides and proteins are both made of amino acids, but peptides are much shorter chains than proteins. Proteins are larger, more complex molecules that provide structure and carry out many of the body's major functions. Peptides often help regulate those functions by acting as signaling molecules that tell the body when to start or stop specific processes.
Some peptides may be more easily absorbed by the body because they are smaller than proteins. Certain peptides can pass through the skin or intestines and enter the bloodstream more readily than larger proteins, although this varies depending on the specific peptide and how it is delivered.
What do peptides do in your body?
Peptides help regulate many important processes in the body by acting as chemical messengers that allow cells to communicate. What they do in the body depends on the specific peptide.
Some peptides, including glucagon-like peptide-1 (GLP-1), occur naturally in the body. Scientists have also developed GLP-1 medications that mimic these naturally occurring peptides to treat conditions such as type 2 diabetes and obesity. The clinical use of GLP-1 medications has exceeded the science. For example, GLP-1 medications may have benefits beyond their current FDA approval for type 2 diabetes and obesity and research is ongoing for use in cancer, Alzheimer’s and addiction.
Peptides can also be found in foods. Researchers are studying whether these food-derived peptides may provide health benefits beyond basic nutrition. A review of studies published between 2019 and 2024 suggest that peptides may help support metabolism, the immune system and muscle and bone health.
Researchers are also studying peptide therapies as potential treatments for conditions such as obesity, aging and metabolic syndrome. While some peptide-based medications are U.S. Food and Drug Administration (FDA)-approved and supported by strong scientific evidence, many newer peptide therapies remain experimental and require additional research to determine their safety, effectiveness and appropriate use.
Why are peptide-based medicines becoming more common?
Peptide-based medicines are gaining attention because they can target diseases that are difficult to treat. Over the last decade, peptide therapies have accounted for about 8% of new FDA-approved drugs. Researchers are also finding new ways to improve peptide medicines so they last longer in the body and work more effectively, which has led to treatments such as semaglutide and other promising drug candidates.
What are some examples of peptides and peptide-based medications?
Here are some common examples of FDA-approved peptides and peptide-based medications:
Are peptide therapies safe?
Many peptide-based medications, including insulin, semaglutide and tirzepatide, have been rigorously tested in clinical trials. These medications have well-established safety profiles when prescribed by a healthcare provider and used as directed.
However, not all peptide products have the same level of testing. Unregulated products sold online or in wellness clinics may have limited evidence to support safety and effectiveness. The American Medical Association advises people to be cautious about injectable peptides that are promoted for weight loss, muscle growth, recovery and anti-aging.
Most of the evidence for these newer peptides comes from animal studies or very small human trials. Although some early research suggests they may help with recovery or pain, there is not enough evidence to know whether they are safe or effective for most people. Researchers also know little about the long-term effects, proper dosing or who should use them. Patients with chronic illness, histories of cancers or on other medications should avoid peptides unless they are under medical care, as interactions and impact on cancers and chronic illness are not understood.
Another concern is that many newer peptides are sold through wellness clinics, online retailers and other sources that are not regulated by the FDA. This raises questions about product quality, contamination and whether the ingredients match what is listed on the label.
Related: Influencers Love Peptides, But Are They Safe and Effective?
How do peptide therapies work, and how are they different from other types of medicines?
Peptide therapies work by attaching to specific receptors on cells and sending signals that help control processes in the body. They can act like hormones, growth factors or other natural messengers. Compared with larger biologic drugs, peptides are less likely to trigger an immune reaction and can cost less to produce.
Peptide therapies also have some advantages over traditional small-molecule drugs. Because peptides are larger and more targeted, they can interact with certain proteins more precisely, which may reduce unwanted effects on other parts of the body. However, peptides also have challenges. They usually cannot easily enter cells, so most peptide drugs work on targets outside the cell. They also break down quickly in the body, which can make them less stable and shorten how long they remain effective. Researchers are developing new ways to improve peptide therapies so they last longer and can reach more treatment targets.
What are the side effects of peptide therapies?
According to the American Medical Association, commonly reported side effects include injection-site reactions, headaches, fatigue and digestive problems. But there may be additional risks that are not yet understood, especially for peptides sold in wellness clinics where quality is compromised. People who wish to use non-FDA approved peptide therapies should talk with their provider to determine whether a treatment is safe, appropriate and supported by scientific evidence.
Are non-prescription peptides safe?
Non-prescription peptides – also known as gray-market peptides – are products sold outside the traditional prescription drug system, often online or through wellness clinics. They can be marketed for weight loss, muscle growth, injury recovery, anti-aging or longevity. Many are not approved by the FDA for those uses. Some are promoted to customers despite being labeled "for research use only" or "not for human consumption."
Medical professionals and researchers have concerns about the safety, quality and effectiveness of products made without FDA oversight and used without medical supervision. Talk with a healthcare provider before using any peptide product, especially one purchased outside regulated medical channels.
How are peptide therapies used in medicine, and what does the future of peptide-based treatments look like?
Peptide therapies are used to help diagnose and treat a variety of health conditions, including diabetes, obesity, cancer and some rare diseases. Advances in science and technology have helped researchers design better peptide-based treatments that can last longer in the body and work more effectively. New tools, including artificial intelligence, improved drug delivery systems and bioengineering, have sped up the development of peptide therapies. Researchers are also studying peptides for use in vaccines, targeted drug delivery and diagnostic tests. As research continues, peptide-based treatments may allow doctors to create more personalized therapies that are tailored to a patient's specific health needs.
When should people talk to their healthcare provider about peptides?
Talk with your healthcare provider if you're considering using a peptide product or treatment. This is especially important if you're thinking about using injectable peptides marketed for weight loss, muscle growth, anti-aging or athletic performance, as many of these products have not been approved by the FDA and may have limited evidence supporting their safety or effectiveness.
Your provider can discuss the peptide’s potential benefits and risks, review possible side effects or medication interactions, and recommend treatments that are supported by scientific evidence.
Key points:
Peptides are short chains of amino acids that help regulate important functions throughout the body.
Your body naturally produces peptides, and scientists have developed peptide-based medications to treat certain medical conditions.
Some peptide medications, including insulin and GLP-1 drugs, are FDA-approved and supported by strong scientific evidence.
Many injectable peptides marketed for anti-aging, muscle growth and wellness remain experimental and have not been thoroughly studied in humans.
Talk with your healthcare provider before using peptide products, especially those purchased online or outside regulated medical channels.
Sources:
Can GLP-1s help reduce the risk of cancer? GLP-1 medications get at the heart of addiction: study
The discovery of insulin: an important milestone in the history of medicine
From lead to market: chemical approaches to transform peptides into therapeutics
Therapeutic peptides: current applications and future direction
What doctors want patients to know about injectable peptides
Editor’s note: The information provided is for informational purposes only and is not intended as medical advice. Please consult your doctor or another qualified healthcare professional for guidance about your specific health needs.
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