Peptides and Longevity: Do These $200 Anti-Aging Shots Actually Work?

Inside the booming world of peptide injections: what the science really says about recovery, fat loss, and longevity[lon-jev-i-tee]nounLiving a long life; influenced by genetics, environment, and lifestyle.Learn MoreClose.

If you’ve listened to top longevity podcasters like Peter Attia or Andrew Huberman, dove into “biohacking[bahy-oh-hak-ing]nounOptimizing biology using science, technology, and lifestyle changes.Learn MoreClose” forums, or even listened to the king of MAHA himself, Robert Kennedy, Jr., you’ve probably heard the gospel of peptides.

If you haven’t, here’s the short version. These short chains of amino acids are often injected, sometimes swallowed in pill form, and there’s seemingly one for everything: They’re purported to help with healing from injuries, as with BPC-157, the most popular of the bunch, as well as aid in losing fat, increasing growth hormone levels, and improving mitochondrial health, which may have anti-aging benefits. 

“There’s a lot of promise, but not a lot of evidence right now,” says Shawn Arent, Ph.D., C.S.C.S., chair of the Department of Exercise Science at the University of South Carolina. Many peptides aren’t approved for use by the general population … and may not even have human data backing up their supposed benefits.

Still, people seeking these benefits are paying hundreds of dollars per shot for these peptides, often to take chemicals that are only approved for research purposes. Often purchased from unregulated websites, these substances are taking longevity and anti-aging seekers into a wild west of unlicensed pharmaceuticals.

Read on to learn more about this gray area of anti-aging, why proponents swear by the shots, and for clarity on the risks and data on peptides from Arent and other experts.

In this article, we’ll go over:

• What are peptides?
• What does the science really say about them?
• Which peptides are FDA-Approved?
• What are the main risks with peptides?
• What questions should you ask your doctor if you’re interested in trying them?

What Are Peptides and Why Are They Suddenly Everywhere?

Peptides are molecules made up of amino acids—the same building blocks that make up proteins—bonded via a condensation reaction. But while proteins can have hundreds of amino acids (and are actually made up of multiple peptides), peptides can be made up of as few as two of these acids. 

They’re important for all kinds of important biological functions: Some peptides are neurotransmitters, delivering messages from the body to the brain. Some hormones are peptides, including one you’ve heard of: Insulin. And like insulin, there are multiple peptides that can be synthesized in a lab, and used for medical purposes: semaglutide and tirzepatide, the active ingredients in the blockbuster diabetes and weight loss drugs Ozempic and Mounjaro, respectively, are both peptides.

But the online craze around peptides isn’t around these well-established drugs: It’s hype for peptides that are believed to boost human growth hormone levels, speed up recovery, reduce levels of visceral fat, or perform a host of other longevity- and life-boosting benefits.

Each of these peptides is already made in the human body, says Chris Renna, D.O., founder of LifeSpan Medicine.

“You and I make thyomosin beta-4 [a peptide that’s purported to speed up wound healing]. Our brains make DHEA,” he says. “We make all these peptides, and when we take peptides exogenously, we’re boosting our peptide activity.”

The Promise: Faster Recovery, Fat Loss, and Anti-Aging Claims

Can these peptides deliver on their promise? In the cases of insulin and Ozempic, yes. But for the myriad other peptide compounds exercisers and longevity-seekers can find online, we’re not always sure of the benefits.

For peptide proponents like Anthony Castore, a strength coach and fellow with Seeds Scientific Research and Performance, the idea is that these compounds “boost the signals” that are bodies are already making.

“When we’re working out, there are certain cellular pathways and signals that we’re sending, our bodies adapt to that stimulus, and that’s where we see results,” says Castore, who calls himself “King of Peptides” on his website. “When you have something like a peptide, what it’s doing is making that signal a little clearer and louder.”

Renna puts it more simply: There are processes in the body that require these peptides, which naturally occur in the body. But sometimes, the amount we’ve got on board isn’t enough, or it falls with age. By taking them by nasal spray, injection, or orally, peptide users should provide more of these raw materials to complete the process and give users the end product they want—less inflammation[in-fluh-mey-shuhn]nounYour body’s response to an illness, injury or something that doesn’t belong in your body (like germs or toxic chemicals).Learn MoreClose, sharper attention, faster injury recovery, and other benefits.

One example Castore gives for his “signal” analogy: When you go for a walk, your body senses that your cells are using up energy, activating the AMPK signaling pathway. This signals to your muscle cells to increase the amount of glucose they take in from your blood so they can make more cellular energy. This process enhances the body’s sensitivity to insulin.

Taking a peptide like mitochondrial open frame terminal C (also called MOTS-c)—which occurs naturally in our body, but decreases with age—should boost the signaling of AMPK, Castore says. This, he says, could make the walk more productive.

What the Science Really Says: No Human Data and a Regulatory Gray Zone

Peptides didn’t explode in popularity because of breakthrough science; they surged because influencers, celebrities, and even politicians started endorsing them publicly. Many of these compounds are technically considered unapproved drugs and, depending on how they’re sold, potentially illegal. That’s why U.S. sports authorities have banned several peptides and why the FDA continues to issue warning letters to clinics promoting them.

Anti-agers and athletes looking for an edge are counting on these signal boosts to work, which is why they’re willing to shell out to get them: Peptide shots can cost hundreds of dollars per dose. But the human data backing up their benefits is often limited. MOTS-c, for example, has had preliminary human clinical trials, and may eventually be shown to have key anti-aging benefits through its impacts on mitochondria[mahy-tuh-kon-dree-uh]nounOrganelles in cells responsible for producing energy (ATP), often called the powerhouse of the cell.Learn MoreClose … but it’s not FDA approved for general use.

Other peptides that have become popular in longevity, fitness, and anti-aging circles, have shown lots of promise in rat studies, but have no human data. And other peptides have almost no data behind them at all.

When using most peptides, you won’t be able to take tests to see the resulting levels, Renna says. The amino acids are too small to determine if levels have increased, and testing protocols haven’t been created to see if, for example, BPC-157 levels are up since you started injecting.

Instead, he says, the effectiveness of peptide therapy will be judged based on a person’s clinical response: Are they feeling better and stronger? Healing faster from injury or recovering faster from heavy workouts than before the treatments? These subjective results, he says, are the main driver for whether the treatment is working for a patient.

Peptides as therapeutics fall into a few categories:

FDA approved peptides, with on-label use:

• Insulin fits here, of course, as do GLP-1 medications used for diabetes and weight loss. Ozempic and Wegovy have semaglutides as their active ingredient, while Mounjaro has tirzepatide.

FDA approved peptides, but used off-label:

• These peptides have been approved for use in certain cases, like in patients with HIV or in children, but are being used by people outside those groups who assume they’ll have similar effects. One example is tesamorelin, a peptide approved for patients with HIV that can help reduce visceral fat. Another is sermorelin, a peptide that is used to stimulate human growth hormone release in children with stunted growth, but hasn’t been approved for adults.

Not FDA approved, but the peptide has limited human data:

• The long-term outcomes of these are often unknown, or there are questions about other, downstream effects. MOTS-c and Elamipretide, a mitochondria-booster, fall into this category.

Not FDA approved, and the peptide only has animal data:

• BPC-157, one of the most popular peptides for its purported help in healing from injury, has most of its clinical data from animal and cell models. While it’s been in a few studies to show that it’s safe for humans, it hasn’t been shown to be efficacious.

For peptides with promising data from animal studies, the potential for these compounds can look remarkable, says Mike Nelson, Ph.D., adjunct professor at the Carrick Institute and founder of Extreme Human Performance. But the results may not transfer to humans.

“We have lots of examples in the supplement realm that work really well in animals, but don’t in humans,” he says. One example is conjugated linoleic acid, or CLA, a fatty acid found in dairy products. “It’s amazing if you’re a rat: You see body recomposition, you gain muscle, you see fat loss. But we’ve got multiple human trials now, and in humans, it doesn’t do hardly anything.”

This could be the case, too, he says, for peptides being touted on the basis of animal research. A 2024 analysis found that only 5 percent of medical therapeutics that work on animals wind up being approved for human use.

There are even some peptides that haven’t been researched basically at all.

“This is just like, ‘hey, we see this peptide show up in the body, and it apparently does [a certain function.] So we’re going to inject it, and it should do the same thing,’” Arent says. That, he says, isn’t necessarily how these compounds will work.

This leaves many peptides in a regulatory gray area: They’re not approved for human use, and don’t have strong human data to back up the claims made about their benefits. Castore and other peptide lovers use these substances, though, and say they’re seeing those benefits. In some cases, this could be a placebo effect. That may not be the case across the board, though: BPC-157, a popular peptide touted for its bone- and joint-healing effects by influencers and Secretary of Health and Human Services Robert F. Kennedy, Jr., was banned by the World Anti-Doping Agency for use by athletes in 2022. 

Peptide Safety Risks You Should Know

You might be thinking, “what’s the harm?” If you’ve got the cash to sink into peptide treatments, and they don’t end up working, they’ll just pass out of your body … and you’ll have just lost money … right?

“It’s interesting how many people are approaching these as positive at best, and neutral at worst,” Arent says. But, especially when diving into the substances that aren’t FDA-approved, there are potential risks with peptide use:

• Risk 1: What’s in it?: Since many peptides are sold on unregulated websites, you may not always know what you’re getting, Nelson says. The label may say it’s the peptide you’re after, but there’s no regulation proving that the substance matches the label. In worst cases, you also don’t know the sterility of the facility in which it was packaged, or how the product was handled (or the temperatures it was subjected to) before reaching your door.

In Castore’s case, he works with a compounding pharmacy to ensure that the peptides he (and the physician he works with) recommends are real.

Renna says that’s not far enough: The compounding pharmacy should be a “clinical” compounding pharmacy, not a “research” compounding pharmacy. This distinction means that the products are certified for human use, and the pharmacy will be legally liable if it turns out they’re not. With a “research” pharmacy, you’ve got no such protections.

• Risk 2: Unknown side effects: Because there have not been large human trials, injecting these peptides may create side effects. And these could be exacerbated because of the delivery system, Nelson says.

“You’re bypassing some of the body’s safety mechanisms because you’re injecting,” he says. “You’re not going to have much, or any, detoxification by the liver. And then, also, people forget about sterility. Hopefully the company that made the product made it sterile, because there are case reports of people injecting something that isn’t sterile and having all sorts of issues.”

• Risk 3: Potential downstream effects: This, Arent says, is the real worst-case scenario of dealing with substances that haven’t been approved as safe for humans. 

“Because we don’t know dosing, timing, and other potential effects in humans, we can’t necessarily say there couldn’t be other downstream effects we aren’t accounting for. We don’t know, for example, about cellular growth. I’m not saying there could be cancer implications,” but it’s not impossible, he says. Tesamorelin, for example, encourages rapid cell growth,  “Could there be an immune response that creates an autoimmune type of regulation that’s trying to reject these ‘foreign invaders’? We don’t full know, because we don’t know how they’re all manufactured from manufacturer to manufacturer.”
That’s not just scare-mongering: Some of the most popular peptides, including BPC-157 and CJC-1295, a peptide touted for increasing growth hormone, have been flagged by the FDA for potential “immunogenicity,” the type of immune response Arent mentions here.

3 Questions to Ask Your Doctor About Peptides

For some Super Agers, the risks and unknowns of peptides are worth the potential benefits they’ve heard about from others, or read about online. If you’re keen on trying these substances out for your own injury or workout recovery, or to boost cognition and memory, you’ll want the experience to be safe, Renna says. That means safe dosing levels of peptides whose ingredients and packaging you can trust, all prescribed by a physician who is knowledgeable about them.

Getting that information from a doctor is important, but doing so can be somewhat delicate, he says. 

“It’s important because, as a patient, you want to know the extent of the physician’s experience and expertise with peptides. At the same time, you don’t want to alienate the physician by challenging them about their credentials,” he says. Doctors have spent years training, and the white coat is hard-earned. Giving a doctor the third degree is simply going to turn them off, rather than helping you get the information you’re after.

To do so, Renna suggests asking the following three questions … and the answers you should listen for.

• Question 1: “Peptides are new to me, and I wonder how new they are to you. How long have you been using peptides in your practice?”

The answer you’ve hoping for: This question introduces the conversation as something you’re interested in, and helps move towards asking about training. Renna says you’ll want to hear that the physician has been using peptides for several years, and uses them as complementary treatments.

• Question 2: “I’m so interested in this. Where does a doctor like you learn about peptides?”

The answer you’re hoping for: “What you want the doctor to say is there are courses that we take after graduating from medical school and being in practice for a few years, and they teach us about these innovative methods,” he says. The doctor may list specific peptide-related courses they’ve taken, or where. Hearing this, Renna says, will help you get the reassurance that the doctor has done their homework.

• Question/Statement 3: “I know peptides are still being developed and are utilized in a lot of research programs. I’d be more comfortable getting my peptides from a clinical pharmacy as opposed to a research pharmacy.”

The answer you’re looking for: For starters, Renna says, you’ll want the doctor to tell you they’re using a clinical pharmacy. This means the peptides are certified for human use. Peptides from a research compounding pharmacy can be much cheaper, but they’ll be affixed with a sticker that says “not for human use.” This means you don’t know if the peptides are safe, and if they aren’t, you won’t have legal recourse.

Going beyond just being a clinical pharmacy he says, see if the pharmacy the doctor uses is “CGMP” certified. This certification means that the pharmacy is not just clinical, but follows specific regulations governed by the U.S. Food and Drug Administration for safety.

“This means the FDA has gone in and looked at the amino acids being sold, to be put into a buffered solution that you can put in your refrigerator for a month without it growing bacteria,” Renna says. This way, when using the same vial for multiple injections, you’ll be safe.

Finally, the CGMP (or GMP) pharmacy should use USP-certified sources for its ingredients. USP is an independent, non-profit organization that independently verifies that ingredients in medicines, supplements, and substances like peptides.

Navigating the World of Peptides Safely

Working with peptides that don’t have much human data requires making a lot of assumptions, Arent says—about dosing amounts and timing, how the substances will be absorbed in human blood, and even about safety.

“We’re treating a lot of unknowns as if they’re knowns,” he says. For those with encouraging animal results, he says he’d like to know: “As a potential end user potentially from injury and aging, I would love to see some human clinical data.”

But with such encouraging animal data and no human trials, the lack of forward movement by pharmaceutical companies—who don’t give up when billions of dollars could potentially be made—is a red flag. “I know there are some where trials were started, and nothing came of them … why did those trials stop?”

Another potential problem, he says: Because they’re not medicines and they’re not regulated, peptides can be recommended and “prescribed” by physical therapists, chiropractors, and others who are not qualified in pharmacology. 

This wild west atmosphere, including research chemicals that aren’t approved for human use, is why using Renna’s three-question system above is crucial for safety.

Even when you’ve ensured their safety, Castore says, peptides should not be considered standalone magic bullets for health and longevity.

“We need to think about it like a pyramid,” he says. The base levels of the pyramid are diet, exercise, recovery, rest, and the other basics of healthy longevity. And on the top? “Once we have all those things in place, that’s where peptides really work their magic.”

For now, the peak of that pyramid is cloudy: There’s so much we don’t know about these substances, their efficacy, or their safety for humans. Peptides, Nelson says, are a massive unknown.

“If you’d have come to me 10 years ago and said we’ll have a drug that’s so effective that people will stop eating so much, they’ll start losing body mass, I would have said you were out of your tree,” he says. But the peptides behind these weight loss drugs do exist, and they’re amazing. But for trendier peptides that have no human data, they could wind up working … or not. And they could be dangerous.

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