Peptides: Hype or Miracle? | Lifespan with Dr. David Sinclair - S2, Ep. 11
In a Nutshell
Peptides like GLP-1 drugs have normalized self-injection and triggered widespread interest in using them for longevity, but most remain in a regulatory gray area with limited human data. GHK-copper may aid protein recycling and stem cell function, Epitalon could activate telomerase and epigenetic repair, and Apelin shows promise for preserving muscle and autophagy, yet long-term safety is unknown. Without controlled trials, people are self-experimenting on unproven compounds whose side effects and lifespan effects remain speculative.
These notes were generated by AI and may contain inaccuracies.
Two hours prior, a statement was made about small peptides that was completely amazing. Thousands of small peptides have been found that turned out to have been overlooked for the past twenty years or more. One peptide can increase telomeres and possibly prolong life. In the future, a range of different peptides will help extend lifespan. Known side effects have been documented in clinical trials.
Peptides are useful for big autophagy, stem cell depletion problems, and improving communication between cells. Peptide-based medicines have been a part of lives for a very long time. David Sinclair is a scientist and professor working to understand why we age and discover new ways to slow down and reverse the aging process.
The episode examines which wellness peptides have real scientific basis, which are media hype, and whether any can affect aging. This follows a previous episode about GLP-1 drugs. The first part covers what peptides are, why they became popular, why difficult to study, and the regulatory gray area. The science from a longevity perspective will be discussed, identifying peptides with interesting biology and where evidence precedes media hype.
Neither David Sinclair nor Matt are doctors, so nothing discussed should be considered medical advice. This is information to discuss with a doctor. Lifespan magazine is now available with early access to episodes, longevity newsletter, clinical trial updates, Q&A sessions, exclusive interviews, and more. Options include a free copy, $8-a-month membership, and Founder's membership granting lifetime access with bonus materials and personal gifts.
Matt Blunt joins as co-author and friend. Peptides are now a common topic worldwide. The discussion will cover history, side effects, FDA's view, what's legal, gray area, illegal, future implications, and most importantly, implications for aging. New ideas exist about what peptides might actually do to bodies of people who take them. Many people are considering taking peptides or already taking many of them.
GLP-1 drugs are modifications of the body's own peptide and act as agonists of GLP-1 receptors. Beyond patient benefits, GLP-1 drugs made home injections socially acceptable. Ten years ago, injecting substances was met with surprise. GLP-1 drugs changed this perception. The new wave of peptide interest is partly because GLP-1 drugs normalized injecting substances even when effectiveness was unknown.
Blood glucose monitors were worn a few years ago, with doctors saying they were unnecessary without diabetes. Now they're worn casually. The same applies to wearable devices. Peptides are now the big trend, especially in Los Angeles and Vancouver.
Los Angeles is the starting point for biohacking due to fitness culture, beauty culture, and having money. Serena, David Sinclair's partner, works in longevity in Los Angeles. Vancouver residents wonder why Canada is mentioned - Serena and David were giving a lecture in Canada when going through security, a border guard asked about peptides for sleep.
The question from airport security in Vancouver indicates peptides have gone global beyond Los Angeles. People constantly ask about peptides. Previously questions were about NMN dosage, before that resveratrol. Now questions are about peptides. Conversations occur on the street when recognized.
At a party in Italy for a 70th birthday lasting five days, every meal conversation turned to peptides. The entertainment included Elton John as the first act on the first night, Mariah Carey the following night, Earth, Wind and Fire at lunch the next day, and John Legend concluding the event.
David Sinclair's lab has a project for 8 to 10 years identifying dark proteins or dark genomes. These are very small genes that algorithms overlooked. Thousands of small peptides found using serum mass spectrometry in bodies were overlooked for twenty years or more. GLP-1 and derivatives have tremendous impact on global economy. Much more remains to discover.
A peptide is two amino acids linked by a peptide bond. Most compounds called peptides are less than 50 amino acids long. The distinction between peptide and protein depends on length. With 20 standard amino acids and combinations from 2 to 50 amino acids, there are approximately 10 to the power of 65 different combinations.
Peptides have a history dating back more than 100 years. Biological materials like longer peptides and proteins are newer than 20th century chemical medicines. Peptides are old but new, and micropeptides are newer. GLP-1 breakthrough increased awareness and encouraged pharmaceutical companies and doctors to explore more.
Insulin is a peptide. Oxytocin and glucagon have been used for a long time in medical circles. Studying peptides is relatively difficult because they don't decompose easily and cannot be swallowed for large doses - injection is required, making human administration and laboratory study more difficult.
Peptides are increasingly available as molecules introduced through skin. The newer method, especially for GLP-1, converts them to be absorbed by the digestive tract. Research suggests the portal vein contains opioid receptors that sense peptides from food. This system might be harnessed to deliver peptides normally not taken into bodies.
Changing just one amino acid in the chain can have profound effects. Denmark's GDP changed due to GLP-1 drugs. Changing amino acid number two prevents peptide degradation, extending half-life from minutes to a week.
Patents are difficult to protect because changing one amino acid creates a different peptide. It's easy to manipulate peptides but difficult to test them. There are very good patents for SS31, MOS C, and Humanin, but protecting them from the gray market is essentially impossible.
Testing peptides for lifespan effects in mice is difficult because they must be injected rather than put in food, causing stress that shortens lifespan. Danica Chen's paper in Nature showed semaglutide extended female mouse lifespan by 12%, but was criticized because normal mice lived shorter due to handling stress. There are very few life-extension trials using peptides for this reason.
Yeast is too small to contain peptides inside. Yeast has a mating hormone but only needs to send signals between family members in a dish. Humans are extremely complex beings requiring signals from head to toes. The more complex on the evolutionary ladder, the more hormones needed. Laboratory tests starting with simpler organisms cannot work because they don't have many peptides.
Testing in small model organisms is difficult. Patenting is difficult. Registration of patents is difficult. There is not much money promised to support research costing tens of millions of dollars. Patents are easy to circumvent by changing one amino acid position.
The gray market exists for peptide families, derivatives, and salts because patents are difficult to protect. Most peptide derivatives and precursors come from China in tons via planes and ships. The federal administration is friendly toward peptides, with Robert Kennedy Jr. stating on Joe Rogan that peptides should be more freely available.
The FDA recommended against approving peptides for general use, but another committee opposes and may allow use for research purposes. Many people buy peptides under the guise of research purposes and conduct research on their own bodies. This is the legal loophole.
Clinical studies are conducted under placebo-controlled conditions, but peptide experiments are being conducted across Los Angeles, Canada, and worldwide without controls. This is an uncensored experiment. The goal is to distinguish fiction from reality so people can evaluate claims about BPC 157, Tesmorelin, and others.
Many patients are hesitant to talk to doctors about peptides fearing they will be asked to do something illegal or unethical. There are storytellers who give out peptides secretly. There is a completely gray market or very dark gray market. Forensic doctors will have conversations about peptides. If a doctor refuses to have that conversation, they are not ready to help.
Most people do not go to their regular doctor because regular doctors are too conservative, and they are typically trained to be that way. There is another type of doctor and practitioner who will provide anything requested. The internet allows people to request peptides to be shipped directly without seeing a doctor, which would have seemed crazy when the book "Lifespan" was written. People can now access not only medicines that are on the market but medicines that have not yet been released to the market, and these are not subject to the level of testing expected from an approved drug.
Most of the peptides discussed are not very toxic, and many people take them in high doses and frequently. However, the long-term effects are unknown, and there are reasons to believe that long-term use of some of these peptides may be very bad for health and longevity.
Peptides fall into different categories. There are legitimate drugs approved by the FDA and prescribed by doctors, such as GLP-1 receptor agonists. There are other peptides that are chains of amino acids structurally similar but not approved by the FDA. On July 24, 2026, the FDA's Formulations Advisory Committee voted to include at least six of them in the 503A list of bulk substances, which would make selling them less illegal and place them in a gray area. Collagen peptides are available at grocery stores and are not subject to control because they are already present in the food supply, making them supplements rather than drugs.
Collagen peptides are biologically active. Proline hydroxylation creates special prolines containing hydroxyl groups found especially in collagen. When collagen is taken, it activates certain survival pathways and can activate mTOR to help with growth and activation of hyaluronan, making hyaluronic acid beneficial for skin. There is reasonable science supporting collagen peptides.
The number of scientific articles focusing on peptides in aging has doubled almost every decade since the 1990s. There was a huge increase in interest in 2026. Northeastern University published an article entitled "Longevity medicine goes peptide madness," and the following day Cedars-Sinai published "Are Peptides Really a Wonder Drug for Anti-Aging?"
The hallmarks of aging were developed after scientists studying life extension were arguing about which pathway, protein, or gene was more important. Linda Partridge, Ido Kramer, and others wrote an article based on research entitled "Cancer Traits," which has been cited extensively. The hallmarks were drawn as a pie chart with equal pieces for major theories about why we age. The hallmarks include mitochondrial dysfunction, protein homeostasis decline (protein balance problems), nutrient sensing problems, stem cell loss, telomere attrition (chromosome ends), senescent cells, DNA damage, and inflammation. Epigenetic changes are one of the things worked on. The framework is useful because any intervention can be evaluated by asking whether it works across all these distinctive features, and if so, it likely affects aging.
One company relied on for more than a decade is Wings. The Wings body scale measures body fat, muscle mass, visceral fat, and includes an FDA-approved electrocardiogram. After making dietary changes and returning to a normal routine, body fat was monitored decreasing while maintaining muscle mass. Wings products have been used for over 10 years, and their watches track heart rate, sleep, activity, temperature trends, and blood oxygen. The "Wings Silver Scan Nova" watch resembles an expensive dive watch. Wings also makes a blood pressure monitor and a sleep analysis device, plus a smart thermometer.
GLP-1 inducers were discussed in another episode as peptides that should be considered life-extending drugs, so they will not be included in this conversation. This is not a supplement set, and there are entire websites dedicated to this. The focus is on peptides that are interesting from a research perspective, show promising results, and need further study.
Genetic instability and protein imbalance are two hallmarks discussed together. Genetic instability can affect healthy protein functioning, and impaired protein function can make it difficult for cells to repair DNA damage. GHK copper is an interesting peptide studied for its effects at the intersection of these two traits. GHK is made up of glycine (G), histidine (H), and lysine (K). It is very small, consisting of three amino acids, and is similar to glutathione. The compound binds to copper and appears to be one of the ways cells bring copper into them. Copper is needed for many reasons, including binding collagen fibers together. GHK-Cu is the abbreviation for GHK and copper. GHK can be obtained without copper for people who want to continue using the peptide but do not want to overdo copper. Some benefits have been found from taking the peptide alone. There are indications it may help with stem cell function, and some people use the copper version intermittently.
The enzyme SOD1, copper-zinc superoxide dismutase, is needed to survive against free radicals produced by metabolism, especially in mitochondria. The enzyme will not work if it does not contain copper. As aging occurs, GHK has been found to decrease from 200 nanograms per milliliter when young to 80 when older after middle age.
Dr. Lauren Pickart was the true advocate for this cause. GHK has been discovered to help the cell get rid of old proteins. Harmful covalent bonds occur, and there is "jalaza," which is probably the worst, described as a "caramelization" process where glucose adheres at high levels to proteins. Albumin found in the blood can be mixed with glucose and after waiting a week, 20-25% becomes linked to sugar. This happens inside bodies when exposed to caramelization whenever sugar is consumed. Advanced glycation end products or AGEs are formed. A fascinating research paper emerged about a bioengineered bacterial enzyme that can remove these substances. GHK appears important for stimulating the body's natural process of recycling old proteins. The GHK peptide is already widely available online in the gray market. GHK falls into Class I, which means it is less grey. The FDA is turning a blind eye to it, having the discretion not to prosecute. It is more like a pale gray than a dark metallic gray.
Epigenetic changes are the systems that control DNA. There are about 20,000 genes or more, but they should not all be working all the time or in the same cells. A skin cell must be a skin cell with certain genes turned on and others turned off. As aging occurs, largely due to DNA breaks causing epigenetic noise, genes that should be working are activated and genes that should be activated are deactivated, and cells lose their identity. The lab tries to figure out how to restart that original program. Both telomere shortening and epigenetic changes are affected by a peptide called epitalon, sometimes called epithelial or AEDG. AEDG are the amino acids: alanine, glutamic acid, aspartic acid, and glycine. This peptide emerged from the Eastern Bloc, originally discovered in Russia or Croatia. There is a lot of cell culture data, but human data is very limited and even animal data is limited. This peptide may increase telomeres and possibly prolong life. There was a negative study on mice when this peptide was injected, but mouse studies are extremely difficult because the animal has to be handled a lot and gets stressed.
Each chromosome is linear and about 6 feet long if put from tail to head. When born, telomeres are very long, but when copying occurs, it cannot copy completely to the ends. As copying occurs, telomeres get shorter and shorter. Over time, in tissues like the liver that divide a lot or the immune system, telomeres erode to the point where cells sense the end of a chromosome as a broken chromosome. It is no longer protected because there are usually protein coverings at the end. This exposure of bare DNA end due to erosion causes the cell to stop dividing and enter cellular senescence.
Histone proteins are small balls that DNA wraps around. DNA does not flounder in the fluid inside the cell in the nucleus. When chromosomes are seen in YouTube videos, what is being looked at is DNA with a Velcro strip representing DNA. Small knobs represent methyl groups that control how genes are regulated. The epigenetic clock in biology is represented by these methyl groups. Epitalon shows association with the third, second, and fourth versions of these histones. When it does that, it unlocks the DNA, allowing it to be read. It is a way to activate genes and control the epigenetic genome through this peptide. It is believed this may help promote health and reveal genes that may be beneficial for repair and survival. The ability of this peptide to activate the telomerase enzyme is interesting because as adults, this enzyme is not active in most cells, and telomeres get shorter. The telomerase gene is still there but is disabled by methyl groups. This peptide appears to help remove it and unlocks the (H2) gene at least in the laboratory. Much of this still needs to be proven in humans.
Long-term safety is not entirely clear for Epitalon. To knowledge, there have been no long-term studies on Epitalon.
Autophagy is the process by which a cell gets rid of old proteins, a waste recycling system within the cell. Stem cell depletion, especially of bone marrow supply, is really bad and is one of the reasons infections occur frequently. Preserving stem cell function is important, and this applies to fertility if having children at a later age is desired. Changes in communication between cells is how organs communicate with each other, and this fades as aging occurs.
Apelin is backed by some really strong science, though still in early stages. Pharmaceutical companies are interested in this. It is known as exirkin, a peptide released when exercise occurs. Apelin was first isolated from the stomach of a cow.
Instead of looking at the dogs' stomach juices and trying to figure out what was inside or the serum, which is what we did, they already knew there was a receptor, a protein that looks for a peptide called APJ. They found it. It is this apelin that was present in the gastric acid secretions of cows.
There is a very interesting research paper from 2018. This research paper took apelin and gave it to elderly mice and found that it did indeed reduce sarcopenia, which is muscle loss as we age. We all experience this and there isn't much that can be done about it other than exercising. This research paper from 2018 has launched a number of companies, including one called BioAge, which is owned by Christine Fortney, someone I greatly admire, to turn this into a drug, and it's still going on. They encountered some obstacles. They conducted a failed experiment that we were talking about earlier. But I really like this research paper.
If we can move to the next figure, you will see that people who exercise, and this is the top graph, have more apelin in their system. Thus, it is not evidence that humans use apelin to improve muscle strength and that it is actually beneficial, but it is certainly a good correlation there. They have indeed found that if someone benefits from exercise, say they get better muscles and become fitter, they usually have higher levels of apelin circulating in their body. They have already traced that back to the mechanism described below.
So, when we are young, the apelin works on the muscle. They know that this is done through the future APJ. But as we get older, there isn't as much apelin, and in fact, it doesn't stimulate muscle regeneration as much. Therefore, it is believed that by injecting this into the elderly, they will be able to face success and turn it into good information. Well, this doesn't work. This doesn't work. This doesn't work. Aha. In attempt number 217, you substitute one amino acid and get a different result. Yes, you are right.
Even with GLP1 drugs, there have been failures along the way in dogs, for example, in the 1940s and 1950s, and nobody stopped. Well, they stopped for 20 years, but they resumed working on it again. They tried again. Yes. Yes. But that's science. Things go wrong. But as long as the original vision is good, and we believe it is, then it relates to this future on the muscle, and at that point it becomes merely an engineering problem.
What we call apelin is actually a collection of different types of peptides, isn't it? Because there are "Apelin 13" and "Apelin 17". Yes, there are a few of them, although there are companies that manufacture different types. There is a large group, and in fact, Andrew, if you showed that chart of what they are, you would see that there is a variety of them, and there is no doubt that there is more engineering going on to remove the toxicity, to make sure that they do not affect the liver too strongly, and also to make them as long-lasting as GLP1 drugs.
So let's talk about this in the context of the defining characteristic "great autophagy". What do we think this peptide does with respect to that distinctive trait? There were two really good research papers on this topic. Yes, it includes our two favorite friends, AMPK and mTor. Therefore, AMPK increases and mTor decreases when you activate the APJ receptor. Remember that was the lock. We have written a lot about that in the book. Yes. Then there is this new protein in this podcast called ULK1, which is being phosphorylated. A small amount of phosphate is added there, and this stimulates a large autophagy program in a variety of tissues.
In fact, a study from late 2025 showed that when mice were treated with this peptide, the results were quite remarkable. They were able to preserve the spinal disc in the backs of these mice. We all, at one stage or another, suffer from disc degeneration in our backs, regardless of whether we stand upright. This may herald that this peptide will one day be used officially not only to preserve autophagy, but also for aspects related to the joints and spine.
What is the relationship between "Apelin" and stem cell depletion? Well, once again our friend "AMPK" is involved in regeneration and research has been published on his ability to preserve mesenchymal stem cells. Therefore, anyone who has undergone stem cell therapy will be familiar with these cells (MSCs), and these papers show that apelin can indeed rescue these stem cells.
Another feature is cell-to-cell communication, which also appears to be influenced by apelin, as it has been found to work in many different ways to help with cell-to-cell communication. Sometimes the cells are adjacent. They communicate through what are called communication gaps. A research paper in the International Journal of Molecular Sciences shows that "Apelin 13" promotes communication through a protein called CX43.
Something we've talked about before in previous podcast episodes is "SASP", which is inflammation secreted by senescent cells. It secretes these substances, which are called the secretory pattern associated with the pyramid, and "apelin" inhibits the pyramid. So if you're full of senescent cells when you get to my age, which we'll all get at some point. Okay. Well, hopefully it's not too bad, but we all have them. So, the damage it causes, especially with regard to inflammation, seems to be actually slowed down by apelin.
Well, I'm thinking now, well, that's good for large autophagies. It is good for depleting stem cells. It is good for variable communication between cells. Why don't I start injecting myself with "apelin" right now? So, talk to your doctor first. This is the first thing that needs to be done. But from a scientific standpoint, "apelin" is very interesting to biotechnology and pharmaceutical companies, as there are some known side effects that have been documented in these clinical trials. A severe drop in blood pressure, an increase in heart rate, dizziness, and overall we don't really know the long-term safety like with most of these substances. Therefore, this does not have a direct path to FDA approval at the moment. Therefore, at the moment, this is not approved by the Food and Drug Administration. You can get it from the gray market, and we have experienced a setback. Until it is released to the market, talk to your doctor to see if it is safe enough to try. But remember again that there have been no long-term safety studies of the products currently on the market.
So, what can you take away from today's episode? Peptides are not new, of course. Our bodies produce them naturally, and drugs such as insulin and GLP-1 therapies have shown how strong and effective they are. What is new is the huge spread of people trying peptides for purposes such as recovery, body composition, metabolism, and perhaps even life extension itself. GHK copper peptide is commonly used for skin and tissue repair. "Epalon" is being promoted for longevity, and "Epilin" is currently being studied for muscle health and metabolism. It appears to work on different aspects of aging. But much of this evidence is still derived from animals. Data relating to humans is still very limited, and its long-term safety is largely unknown.
So, in part two, we will cover peptides that are believed to affect mitochondria, senescent or "zombie" cells, and peptides used in everything from recovery from injuries to sexual desire, cognition, and muscle growth.
Lifespan magazine is now available, along with everything we're building around it to help you live a longer, healthier life. You will receive the wonderful 100-page magazine, early access to episodes of "Lifespan," my email newsletter on longevity, clinical trial updates, Q&A sessions, exclusive interviews, and more to come. Visit lifespan.com to read the journal, see what we are building, and support medical research too. Life is very short. Let's change that together.
"Lifespan" is produced by Andrew "Miracle Man" Ying, Raji "Knowledge Geek" Romesh, Marisa "Initiative" Baltimore, Kathleen "Content Summarizer" Fitzgerald, our researchers Shivani "One More Thing" Sethi, and Adif "Date 3000" Johnson. I would also like to mention our new team member, Daniel "Rocket Man" Salazar, who is our new producer, and of course Serena, my partner. Thank you to our partners for helping us support life extension research; See you in the next episode.
This presentation is for informational purposes only and does not constitute medical advice. Please consult a qualified healthcare provider, as results may vary from person to person. The views expressed are my own and not those of Harvard University or Harvard Medical School. The full disclaimer is in the display notes.
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