A man with a mysterious case of full-body hives in Abu Dhabi. A Californian rushed to the hospital with a life-threatening allergic reaction. A fit, gym-going man in Texas with soaring blood sugar — inexplicably headed for pre-diabetes.

Doctors working on the bleeding edge of longevity care in high-end clinics around the globe — from concierge practices in wealthy enclaves of California to premier longevity centers in the Middle East — say they're seeing an uptick in both interest in, and injuries from, injectable peptides.

A peptide is simply a short chain of amino acids, too short to be called a protein. We have thousands of them in our bodies. Some are hormones like insulin, some help our muscles grow, some aid in healing. Injectable peptides promise people a boost on top of what nature delivers, such as deeper tanning, better fat burning, greater muscle growth, and improved wound healing. Still, rigorous human studies on these claims are often lacking.

As more people attend peptide "parties" and inject unknown substances sourced from friends or online dealers, doctors are sharing horror stories about some of the worst-case DIY peptide scenarios they've seen.

Many say they are putting out "fires" and dealing with bizarre, unexplained health issues that, after some medical investigation, end up being tied to unauthorized, grey-market peptide use. Injuries they've seen range from simple to serious, including minor injection site reactions and major hormonal disturbances.

Recently, at Dr. Nicole Sirotin's Institute for Healthier Living longevity clinic in Abu Dhabi, practitioners linked a case of full-body hives to an at-home peptide injection.

"These kinds of immune reactions," Sirotin said, "people might not be associating with the peptides."

That makes it hard to gauge how widespread peptide injuries are — from simple injection issues, to contamination, or improper dosing. Anecdotally, however, doctors say there's been a huge uptick in peptide use over the past year, fueled by influencers touting their benefits on social media.

Business Insider spoke to seven doctors, including some who use peptides in their practice and some who don't recommend them. They're concerned about growing interest in and willingness to experiment with unauthorized peptides.

Hives, messed-up hormones, and insulin resistance issues

People are drawn to peptides because they promise targeted, almost "shortcut" fixes for weight loss, muscle gain, and antiaging — often with little oversight from doctors.

They act like messengers in the body, influencing or acting as hormones that control growth, metabolism, and other key functions. Because these substances mimic normal hormonal processes in our bodies, they've developed a reputation as safe and "natural," though there are very few rigorous human studies to support that claim.

The effects of "stacking" multiple peptides into a daily or weekly regimen, including ones for fat loss, muscle growth, tanning, better hair and skin, have also not been studied.

Originally, bodybuilders were drawn to peptides for muscle gains and the promised benefits to physique. Then, post-COVID, biohackers were attracted to this style of do-it-yourself medicine, and now doctors told Business Insider that antiaging enthusiasts and affluent patients can't get enough of this stuff.

In Texas, Dr. Farhan Abdullah, the medical director at Magnolia Functional Wellness in suburban Dallas, said that over the past year, he's seen an uptick in moms, housewives, and "white collar people who are kind of approaching middle age" taking an interest in peptides.

"You look at RFK, and you look at what's going on, and you would think it's just a bunch of gym bros that are interested in peptides, and it's really not," he said.

There are dozens of peptides to choose from, and doctors stress that each should be evaluated individually.

Abdullah's patients tell the board-certified physician that they're often skipping the pharmacy, and sourcing their peptides online, or getting them secondhand from friends, like an injectable drug version of a Tupperware party.

In his worst-case scenario to date, one patient, who he described as a young "fit" man, developed early insulin resistance from a growth hormone-stimulating peptide that had him charting a course toward early diabetes. Because growth hormone and insulin counterbalance each other, excess stimulation may lead to insulin resistance, a risk not well studied in peptide use.

"This guy with no family history, he was a fit dude, he was jacked, he was working in the gym, had early insulin resistance," Farhan said.

Dr. Meena Verma, who runs Blue Coast Longevity clinic in Newport Beach, California, said one of her patients had a severe, life-threatening allergic reaction to a peptide shot and landed in the hospital "that night."

"Obviously, we see it all over social media — Instagram influencers — everybody is pitching peptides," she said. "Where the patients are getting their peptides is a big concern."

Dr. Lisa Cassileth, a plastic surgeon in Beverly Hills, said the worst issues she has seen so far have been minor, such as injection-site redness from unsterile pokes or improper storage of peptides. Other issues with peptide injections can stem from contamination issues.

Not all doctors are entirely against peptides, especially when used in controlled settings. Cassileth prescribes some peptides to her patients when they are recovering from surgery, but wouldn't recommend injecting them all the time or obtaining them from online sellers.

"Peptides are just going to be another drug," Cassileth, founder and CEO of The Practice Healthcare, said. "We just have to learn how to use them correctly."

Cassileth uses the very popular "Wolverine" peptide BPC-157, a compound that will be up for debate at a July FDA meeting. It is often sold online "for research purposes only," meaning it's not human-grade.

Cassileth sources hers from state- and federally-regulated compounding pharmacies, licensed as "503A" and "503B," which are held to a higher standard. She said she often uses BPC-157 on her patients after surgery as it's marketed to promote faster wound healing and tissue repair, but said it's not something people should take every day. She called it a "one-week" peptide.

"There's no hormone or enzyme in your body that just hits you nonstop in high doses," she said.

While she believes that the anti-inflammatory and reparative benefits outweigh the risks for short-term use, she wouldn't put someone on it indefinitely. "Don't do excess because you don't know what it does yet," she said.

Cassileth is hopeful that the practice of using peptides will develop into a well-studied approach for various conditions and be marketed by major pharmaceutical companies.

"Pharmaceuticals — go for it," she said. "Please save us from this thing being in some kind of weird space where only functional medicine people prescribe it."

Could peptides solve aging? Maybe someday.

Other longevity-focused doctors take a more measured stance on peptides and said far more research is needed in humans before doctors start prescribing these substances.

Dr. Andrea Maier, a professor of medicine at the National University of Singapore who runs the Chi Longevity Clinic at the Four Seasons there, said that the clinical evidence simply isn't there yet for a lot of these peptides.

"At the moment, we are hearing that peptides could solve the aging trajectory — and I think it might be right," Maier said. "I think we should study it well, to give it in a very well-regulated way."

When she hears of "peptide parties" and "peptide festivals," she worries about the potential for harm, where something is being injected with only "a thought that this might help."

Her concerns aren't just theoretical. Regulators are increasingly scrutinizing the fast-growing peptide market. The FDA has restricted several peptides over safety concerns and warned companies against selling unapproved versions online. In September, the agency announced it was cracking down on imposter versions of the weight loss shots semaglutide, tirzepatide, and retatrutide being imported from abroad.

Canadian authorities recently warned that unauthorized peptides can lead to hormonal imbalances, mood swings, blood sugar issues, organ damage, and tumor growth.

GLP-1 is the darling peptide

There is one all-star peptide that experts across the board said they endorse, use, and would like to study further for its effects on aging and longevity: GLP-1, the hormone-mimicking peptide behind Ozempic and Mounjaro.

"I have like 80% of my patients ask me about GLP-1s and 5% about peptides," Dr. Nima Afshar, a physician at Private Medical San Francisco, told Business Insider. "Even people that are pretty healthy, boy, they're thinking about [GLP-1s] because my patients are rational and they understand this is evidence-based, and it does seem to have some longevity benefit."

He doesn't broadly recommend the entire class of compounds, though. When his patients ask, "Should I be on peptides?" or say, "I've heard peptides can help" for things like an energy boost, improved muscle mass, or better libido, he generally says "no." Though he's open to adjusting that stance in the future as more data comes in.

Dr. Evelyne Bischof, who runs a healthy longevity medicine practice in Shanghai and Tel Aviv, said she is not "radically against" peptide use, but her patients only use FDA-approved peptides like Ozempic, "and only from very reliable providers." She has concerns about unauthorized peptides causing allergic reactions, or including extra substances that aren't listed on the label, like steroids.

"I don't think any scientists would be anti-peptide," Sirotin, the longevity doctor in Abu Dhabi, said. "We're just anti-self-experimentation with random molecules that are research-grade."

"Partly, the reason I think it's so concerning is because these are presumably healthy people who want to be healthier," she said. "The problem is you might be entering a one-way door, and you damage your liver, or you damage your kidneys."

• Harry and Susan Jones own Bridge Avenue Berries, a blueberry farm in Allenwood, Pennsylvania.
• The farm became USDA organic certified in 2021, boosting customer traffic and interest.
• If they had bought the farm 30 years ago, they would have likely grown a more diverse set of crops.

This as-told-to essay is based on a conversation with Harry Jones, 63, who owns and runs Bridge Avenue Berries with his wife, Susan, in Allenwood, Pennsylvania. It has been edited for length and clarity.

Since I was a kid, I'd always wanted to run my own business, but it never quite came together. I tried starting a small tree nursery business, but we couldn't compete with the big nurseries and had to close it.

Then, a blueberry farm that my wife and I had been picking berries at for years went up for sale. When I first mentioned buying it, she said, "Absolutely not."

A few months later, we were there picking blueberries, and the farm still hadn't sold. We started talking with the owner and purchased it in March 2018.

We didn't have much time to figure it out. Blueberry season starts in early July, and we had about four months to get ready.

That first summer, it felt like we were drinking from a fire hose. We were learning everything at once — pests, soil, customers — mostly the hard way.

I wasn't starting from scratch, but owning a farm still surprised me

My background is in horticulture. I have an associate degree in nursery management, and I spent years designing landscapes. So, I've been around plants most of my life.

Still, running a blueberry farm is a different kind of challenge.

We have about 7 acres of blueberries — roughly 3,800 plants — and we harvest around 18,000 pounds a year.

The catch is that it all happens in about a 30-day window in July. That month is intense, but the work doesn't end with the season. The rest of the year is spent on preparing for the next one.

I've kept my full-time job in the lumber industry through all of this. We tend to call the farm my self-supporting hobby, but the truth is, even a small farm like ours struggles to make a dollar.

By the time you pay for inputs, repairs, improvements, and all the other costs that come with a small business, there's not much left.

If I were younger, I'd do it differently

At this stage of life, I think differently about what the farm should be. If I were 25 or 30 years younger, I wouldn't run it the way I do now.

Right now, we're heavily focused on one crop. If I were starting earlier, I'd cut the number of blueberry bushes down — maybe from 3,800 to about 2,000 — and use the rest of the land for other crops. Strawberries, raspberries, pumpkins — something to stretch income across more of the year.

That's the biggest challenge with what we do. When you rely on a single crop and a short season, it's hard to build a stable living.

We've found ways to spread out the income a bit. We freeze blueberries — about 1,900 pounds a year — and sell them through the winter at local markets and to restaurants.

Becoming USDA-certified organic was a game changer

We started farming organically from day one in 2018, but it took time to make it official. To become USDA certified organic, we had to go through a required three-year transition period — documenting everything we did, from fertilizers to pest control, and proving we were following the standards.

We finally got certified in spring 2021, and once we could call our berries "USDA organic," we saw more customers, more traffic, and even people driving an hour or more to pick our fruit.

But over time, the downsides started to add up. The certification cost us about $1,400 a year — a big expense for a small farm — and required inspections and paperwork during our busiest season. More importantly, I grew frustrated with what I saw as inconsistencies in the system.

In early 2024, we gave up our USDA certification and switched to Certified Naturally Grown, a smaller, farmer-led program. It costs about $350 a year and still holds us accountable to the National Organic Program Standards, but in a way that is more transparent and aligned with how we actually farm.

We know we won't do this forever

Realistically, we'll probably run the farm for another three to five years and then look to sell it, so that we can have more freedom to travel and visit our three kids and nine grandchildren.

I think about what a younger person could do with this place. It's a productive farm with a lot of potential. Someone with more time and energy could take it further than we have.

Even knowing what I know now, I'd still buy the farm.

We're happy with what we've built. It gave me a chance to finally run my own business and to work with something I've always loved — plants. And it's been meaningful to us to see people come here, enjoy the farm, and tell us how much they like it.

• Peng Lin Hua, 86, taught physics in China before retirement.
• He still leads an active life — in his 50s, he started doing headstands with his wife.
• Now, he exercises daily, enjoys brisk walks, and can do flips on a pull-up bar.

This as-told-to essay is based on a conversation with Peng Lin Hua, an 86-year-old retiree in Singapore. It has been translated from Mandarin and edited for length and clarity.

Before I retired, I taught physics at a secondary school in China. While working as a teacher, I met my wife at an event. She was a chemistry teacher, and we hit it off right away.

We were as active as the students we taught, spending our free time playing badminton, basketball, volleyball, and table tennis.

In my 50s, I began practicing headstands after learning about the exercise from a Taiwanese health guru. I was already fit, but I was looking for a way to build strength and stave off aging-related illnesses.

Retirement didn't slow us down. My wife and I kept playing sports, and I continued long-distance running.

Most days, I wake up at 5:30 a.m., blend fresh apples into a puree, and have it before heading downstairs with my wife to exercise. We begin with a walk and gradually pick up the pace, incorporating light exercises like stretching along the way.

In the afternoons, at home, I like to sing with my wife. She plays the violin and the erhu, a traditional Chinese two-stringed bowed instrument.

Before I turned 65, I went running every morning. After that, my heart could no longer handle the strain, so I stopped and switched to brisk walking instead.

After that, I focus on building my core and upper-body strength with a series of exercises on the horizontal and parallel bars. I finish off my routine by doing headstands with my wife.

About 20 years ago, my wife and I began traveling regularly to Singapore to visit our daughter, who lives here with her family, and to spend time with our grandchild.

Our granddaughter has since graduated from university and no longer needs looking after, which means we are free to head out for walks and explore on our own.

About 10 years ago, I was exercising at a fitness corner, doing pull-ups and dips on the bars, when a man approached me and struck up a conversation. He joined me for my workout, and we got to know each other.

He told me he was part of a fitness group for older adults and encouraged me to join. That was how I became a member of Team Strong Silvers. We are a group of older adults committed to keeping our bodies strong as we age.

A lot of people don't expect us to move the way we do, so we're sometimes invited to healthy-aging workshops and exercise sessions to demonstrate our workouts and inspire fellow seniors to keep moving.

Now, my wife and I split our time between the two countries, typically spending half the year in Singapore during China's colder autumn and winter months, and returning to China in the spring and summer.

Staying active has spared me many of the aches and fatigue that often trouble older travelers. I rarely feel stiff on long flights or worn out after a full day of walking, and I credit years of regular exercise for that resilience.

• Srdjan Stakic vibe-coded a security camera system for his parents to ensure their safety.
• Stakic used vibe-coding platform Lovable to get started, as well as popular AI chatbots.
• His vibe-coded software became the basis for his AI-assisted startup Alvis.

This as-told-to essay is based on a conversation with Srdjan Stakic, 49, a former film producer who vibe-coded an AI system to monitor his elderly parents and detect falls. He's now launching a company that aims to offer the technology to others. This interview has been edited for length and clarity.

When I was diagnosed with stage four cancer two years ago, AI became essential.

Everything was happening so quickly: The doctors would talk to me for 15 minutes and leave me with more questions than answers. AI gave me an objective way to document and make sense of what was happening.

I'm now in remission. As my health improved, my parents' health declined, and I began helping them with cooking, cleaning, and medical appointments.

English was not their first language, and communicating with healthcare providers was tough. I recorded our conversations with their doctors and compared them to the after-visit summary using AI. I would put together all this information and translate it into Serbian for them.

But I soon wanted more than what the chatbots could offer. I wanted a system that could observe what was happening with my parents, or any other patient, and assess it through the lens of safety and dignity. I would think of how much guilt I'd feel if something happened and I wasn't there. What kind of son would I be?

I had never coded before, and I didn't have millions for an initial investment

I don't have a background in coding. I have a doctorate in health education and a master's in film production, and I have produced some films of my own.

I started outlining my idea with Gemini and ChatGPT to examine it from a tech and ethical standpoint. I built this document of what I wanted to achieve. I kept asking my family how they wanted to be treated in each scenario — like a fall or medical emergency — and I wanted to make the system flexible.

Then I transferred to Lovable. Lovable gave me a live development environment where I could describe what I wanted, see it built in real time, test it, and iterate. It connected the pieces, the frontend, the backend, the database, the authentication, the integrations, things I did not even know I needed until they were there. The chatbots helped me plan. Lovable helped me build.

I uploaded hundreds of training videos for nurses and healthcare providers to train the AI. I created a high-fidelity validation pipeline and a labeled dataset. I labeled real-world caregiving footage with established clinical benchmarks, like Stanford's C-I-CARE framework. When you approach a patient and introduce yourself, you tell them why they're there, you ask the patient's name and pronouns, and you introduce what you're about to do. You explain next steps and see if they have any questions or concerns.

I also started building an AI equipped with cameras to identify falls. I would fall in the middle of my living room and see whether the system recognized that and how long it would take.

It took me a few months to make it work

I tried different cameras and protocols, but ultimately, I had to hire an IT company to help me connect multiple cameras. The system can now identify a fall and send notifications to loved ones or EMS, and provide their location with a brief summary of their health records. The system also analyzes interactions between caregivers and my parents. It's sophisticated enough to analyze in real time — based on audio and video — if a caregiver is being rude or unprofessional. My parents have felt safer since I built this. I also built a feature that scans their environment for any trip hazards, such as cables.

I don't want to spy on my family, so I don't actively review all the video footage. When a concern is flagged, the system clips approximately 30 seconds around that moment and notifies mewith a summary of what it observed and why. It can also generate an advocacy letter from that same analysis: what was said, what was done, and how the interaction compares to the C-I-CARE framework to evaluate caregiver conduct.

I launched a company to offer this tech to others

This all started as an idea for my family, but the more I talk about it, the more people tell me they wish they had this for their parents. So I decided to launch a startup, called Alvis, to make this system available to others.

It detects falls in real time, recognizes when a caregiver goes above and beyond, and generates advocacy letters when something goes wrong. It's in private beta and accepting waitlist applications for our pilot cohort, launching April 13. The model will be a monthly subscription, similar to what families already pay for camera cloud storage, with a premium tier for AI-assisted analytics.

This week, my mom was hospitalized, and I used AI in four ways

First, I used it as a real-time medical interpreter: Every lab result went straight into Claude, so I understood what was happening immediately, not the next morning when a doctor was free.

AI was also my clinical advocate. When a history and physical exam understated her cancer history, Claude caught it. When her glucose started climbing from steroids, Claude flagged it.

Third, I used AI to translate updates into patient-friendly language in both English and Serbian.

Finally, Alvis — the camera system I designed — was running live in her hospital room all night, with her permission and a nod from her care team. It picked up her saying in Serbian, quietly, that she had endured too much. It flagged when I visited, and we recorded ourselves together.

It's amazing to see how vibe coding is democratizing access to AI tools. You can build a company that helps a very niche group that needs a specific thing. I still don't fully understand code or the extent of what I built, but it seems to be working.