The promise of peptides: hype or the key to longevity? 

The promise of peptides: hype or the key to longevity? 

From insulin and GLP-1 medications to experimental longevity treatments, here's what you need to know about the science, promise, and risks of peptides

By Shaun Francis 

Peptides are generating significant interest right now and have become a topic our physicians are frequently being asked about. You can’t turn on the TV, scroll your phone, or read a health publication without coming across the term. 

But what are they exactly? And why are we talking about them? 

The word ‘peptides’ is an umbrella term for a large group of biological messengers involved in countless processes throughout the body. They are being talked about across various medical and wellness arenas, from skincare to longevity, weight loss, and chronic disease prevention. While there is excitement about the promise of peptides, there are also real risks to consider. 

Certain peptides are well researched and considered safe. Topical peptides in your skincare, for example, are generally considered safe with known benefits for skin firmness, elasticity, and collagen production. You might also be surprised to know that some well-established medications also belong to the peptide class, like insulin and GLP-1s, and are supported by decades of research and clinical implementation.  

The current conversation on peptides, however, is moving into more experimental territory. Various peptides are now being widely promoted as a tool for healthy aging and longevity. They're a frequent topic on podcasts, social media feeds, and wellness blogs, where advocates claim they can support everything from recovery and body composition to energy and cognitive function. Some, such as melanotan II, often referred to as the "tanning peptide," are even promoted to enhance skin pigmentation.   

Yet, in many cases, the trend is getting ahead of clinical evidence. So much that a black market of sorts has emerged. Health Canada has warned Canadians not to purchase certain peptide drugs online from unauthorized sellers and has seized multiple injectable peptide products.  

In fact, the growth of peptides has become so widespread that, last month in the United States an FDA advisory committee voted – narrowly, and over the objections of the agency’s own scientists – to recommend that six of seven peptides under review become eligible for pharmacy compounding, even without FDA approval.  The recommendations are not binding, and the FDA will make the final decision. However, the outcome highlights the ongoing debate between expanding access to emerging therapies and maintaining evidence-based standards for patient safety. 

So, what is the actual truth about peptides? I've spoken with leading experts on the topic, including Medcan's longevity physicians, to bring you the evidence-based information you need to know. Here you'll learn that while some peptides have been used safely and effectively in medicine for decades and are supported by extensive research, others remain experimental, with limited human data available. 

While there are valuable use cases for peptides, and it’s an exciting area of research, we must remember that it’s a broad topic with many nuances. Peptides deserve the same level of scientific scrutiny we would expect from any medical intervention – with the rigour we are known for here at Medcan.  Because enthusiasm is not a substitute for evidence, and popularity is not the same as proof. 

What are peptides?  

Peptides are biological messengers that get systems to function in specific ways throughout the body. 

We produce them naturally, but they can also be taken as medications that mimic or amplify certain signals. Peptides play many different roles in the body. As Dr. Steven Poirier, Medcan longevity physician and Clinical Director of Dedicated Care explains, “the body uses peptides as signaling molecules across virtually every organ system.” 

Despite the hype, what many don’t understand is that peptide medications have been used in medicine for decades. One powerful example of one peptide used for medical purposes is insulin.  

In 1921, natural insulin was first isolated from animal pancreases by researchers at the University of Toronto, and then in 1978, synthetic human insulin was created via recombinant DNA technology by combining insulin chains expressed in bacteria. 

“If you had a type 1 diabetes diagnosis before synthetic insulin, you would not survive and there's nothing we could do for you. Then insulin was invented and it was revolutionary,” says Dr. Poirier. 

Another well-known example is GLP-1 receptor agonist medications (known as GLP-1s), which have made waves as a revolutionary medication to treat obesity and help in the prevention and management of diabetes. And the rise of these now widely used medications may be one reason peptides are gaining so much attention in longevity circles. (Curious about GLP-1s? Read our insights here). 

How they work

In basic scientific terms, peptides are keys that act as biological messengers, binding to receptors on cells and triggering signals that tell those cells how to behave. They are made from amino acids – the same building blocks that make up protein, but just a smaller amount – and can influence processes such as metabolism, appetite, growth, inflammation, and tissue repair.  

There are many types of peptides. Some are hormones made by glands, and travel throughout your body to various organs. Some are neurotransmitters, made by neurons (nerve cells), and are specific to the brain and nervous system. Others are structural – like collagen peptides – that support growth, repair and skin health. Beyond that, your body also produces immune peptides to defend against infection, ones for cardiovascular health, and others that are involved in everything from reproduction to gastrointestinal function 

“There are also dietary peptides that get released from food proteins during digestion that help your body fight cell damage, keep blood pressure in check, support your immune system, and lower inflammation,” explains Dr. Poirier. 

Now, peptide research is growing and evolving rapidly because of the possibilities for treating other diseases and optimizing health.  

“Many are excited because of the clinical significance of altered peptide production which has far-reaching clinical consequences across virtually every organ system - from metabolic disease and cardiovascular dysfunction to immune compromise, neuropsychiatric disorders, and accelerated aging,” explains Dr. Poirier. 

So, which peptides are safe? Which ones are not? 

Given that peptides are a drug category and there are many with various functions, some peptide medications are among the most evidence-based treatments in modern medicine, while others remain experimental and require much more research. 

“In the medical community, peptides have become increasingly important therapeutically, with over 60 peptide drugs approved and more than 150 in clinical development, spanning areas from diabetes (insulin, GLP-1 agonists) to cardiovascular disease (natriuretic peptides) and pain management,” shares Dr. Poirier.  

“Their high specificity and low toxicity make them attractive therapeutic agents compared to small molecules.” 

Here are five of the most common ways peptides are used in clinical settings today: 

• Bone health and osteoporosis: certain peptides are used to treat severe osteoporosis by stimulating new bone formation and reducing the risk of fracture. 
• Hormone and reproductive health: peptide medications can regulate reproductive hormone production. They are used to treat conditions such as prostate cancer, breast cancer, endometriosis, uterine fibroids and precocious puberty (when puberty starts early at age 8 or 9). Meanwhile, others are used in fertility and IVF treatments to help control hormone levels. 
• Physical development and body composition: some peptides can influence the growth hormone pathways and are approved to reduce excess visceral abdominal fat in some people with HIV. There are peptides also used to treat growth disorders in children, helping to support normal physical development. 
• Obstetrics: oxytocin is a well-known peptide used every day in hospitals to induce labour and reduce postpartum bleeding.  
• Infectious disease: peptide-based antibiotics are also used to treat certain serious bacterial infections. 

Peptides have attracted significant attention from researchers, clinicians, and longevity enthusiasts alike as targeted tools that may be able to produce all types of significant results that range from: 

• Weight management 
• Healthy aging 
• Injury recovery 
• Body composition optimization 
• Hormonal support 

However, many newer peptides gaining attention in longevity circles are supported by far less evidence. In many cases, the research is limited to animal studies, and when human studies do exist, they are often small, short-term, or preliminary. 

Popular peptides making longevity headlines today, go by odd numerical and letter names like BPC-157, TB-500, CJC-1295, MOTS-c. Each one may have the potential, in future, to do remarkable things from heal tissue, reduce inflammation, to improve mitochondrial health (and boost energy), but the bottom line is: there's limited human clinical evidence to support them, and in many cases the enthusiasm exceeds the available science. 

The overarching message on peptides 

Before any therapy can be considered safe and effective for widespread use, researchers need a clear understanding of its long-term effects. When medications receive regulatory approval, they typically undergo extensive clinical testing to evaluate: 

• Short- and long-term side effects 
• Drug interactions 
• Appropriate dosing 
• Effects across different populations 
• Rare but serious adverse events 

Many peptides marketed for recovery, performance, body composition, or healthy aging have not undergone this level of scrutiny. As a result, significant questions remain about both their safety and effectiveness. 

One of the biggest concerns is the lack of long-term human data. A peptide may appear safe over weeks or months yet produce unintended consequences that only emerge after years of use. For many of today's most popular longevity peptides, those long-term studies simply do not exist. 

Another important consideration is product quality. In many cases, the greatest risk may not be the peptide itself, but where it comes from. Experimental peptides are often purchased from research suppliers rather than pharmaceutical manufacturers. Independent analyses have found that some products contain inaccurate dosages, impurities, contaminants, or even compounds that differ from what is listed on the label.  

“If someone is getting a peptide outside of a medical environment, these are often being made overseas and marketed as a supplement where there is no guarantee of safety and quality. If a drug hasn’t been approved, there could be chemicals and heavy metals in it. This is why medications are regulated,” says Dr. Poirier. 

Finally, because many peptides are administered by injections, users may also face risks related to improper storage, handling, sterility, injection-site reactions, and infection. These concerns become even more significant when products are obtained or used outside a regulated healthcare setting. 

This is precisely why regulators require large, well-designed clinical trials before approving new therapy. While some experimental peptides show promise in early research, many have not yet undergone the rigorous testing needed to establish their long-term safety, effectiveness, and appropriate use. Until that evidence exists, claims about their longevity benefits should be approached with caution. 

“Many of the newer longevity peptides need to be studied appropriately in humans for safety, efficacy, and quality,” says Dr. Poirier. 

At Medcan, our approach is rooted in evidence-based medicine, where we are guided by the principle taught to all healthcare providers to "do no harm." Our physicians prioritize treatments backed by rigorous clinical research and established medical guidelines. While innovation plays an important role in advancing healthcare, new therapies must be supported by robust safety and efficacy data before they are recommended to clients. 

Want the results that peptides promise but are concerned about safety? 

Peptides are being explored for a wide range of potential applications, from weight management and tissue repair to skin health and healthy aging. However, many of the outcomes people hope to achieve with peptides can often be supported through established therapies, lifestyle interventions, or medical treatments that have a stronger evidence base and more clearly understood safety profiles. 

Before considering any peptide therapy, speak with your Medcan physician or family doctor about the specific health goals you're trying to achieve. Understanding your baseline health status, including relevant biomarkers, can help identify the underlying factors contributing to a health concern and determine the safest, most effective path forward.  

Medcan’s Annual Health Assessment can provide valuable insights into your biomarkers, health risks, and opportunities for improvement. Armed with this information, you can work with your physician to develop a personalized plan that is targeted, evidence-based, and, above all, safe.

This article was written by Medcan's CEO Shaun Francis in collaboration from Medcan's editorial team and insights and review from Dr. Steven Poirier, Medcan's Clinical Director of Dedicated Care.

Note: This information is intended for educational purposes and is not a substitute for professional medical advice, diagnosis, or treatment.