In August, an eleven-year-old Australian-German Shepherd mix named Finley suffered a sprain so severe she could barely limp around her Dallas yard. She had lived for years with hereditary joint problems, and her owner, Ryan Samluk, a 29-year-old project manager for a construction company, did the arithmetic: the diagnostics plus arthritis injections at $200 a dose would run to “thousands of dollars I didn’t have.” For about $160, from vendors recommended by friends, Samluk bought Finley a month’s worth of peptide injections — the same unregulated compounds circulating among weightlifters, longevity enthusiasts and online recovery forums. He had watched friends get shredded on retatrutide, a weight-loss peptide, and had heard the injury-and-recovery stories told about BPC-157. He had tried them himself and felt good. Why not the dog?
Samluk is one of a growing number of owners giving dogs peptides, Business Insider reports, often for well under $100. Peptides are a broad class of molecular compounds that keep bodies running — a class that includes insulin and Ozempic — but pet owners concentrate on the subset marketed as hacks for wound healing and arthritis-related inflammation, where the evidence is shaky and the possible risks are not. The trend cuts across income: from owners who spare nothing on elaborate pet-wellness regimens to those who simply cannot afford conventional care. Veterinarians and scientists are watching with caution, uneasy about unknown long-term effects and about one unsettling theoretical question involving cancer.
‘The most measured dog in the world’
The case that made the online rounds, and impressed Samluk, is a 14-year-old pit terrier named Choo Choo. Choo’s owner, Michael Morelli, is a Florida personal trainer preoccupied with body composition and VO2 max; he takes BPC-157 and TB-500 himself — he credits them with resolving a shoulder injury — plus epitalon and pinealon, which he favors for sleep. He follows Bryan Johnson, the tech entrepreneur who has spent millions attempting to age in reverse and recently launched his own peptide label. Johnson calls himself “the most measured man in human history”; Morelli calls Choo the most measured and optimized dog in the world.
Morelli began giving Choo a low dose of BPC-157 and TB-500 — a pairing proponents call the “Wolverine stack” for recovery and tissue repair — about a year ago, when the dog was slowing down, struggling to jump and cutting walks short. Choo’s regimen now runs to two house-call vets, heavy-metal testing, physical therapy, red-light therapy, probiotics and testosterone replacement, a practice some vets increasingly endorse for canine anxiety and mobility. Morelli’s other dog, an American pit bull terrier named Bubba, had already died after a similar decline. “He has become like another kid to us,” Morelli told Business Insider. “I don’t want to go through this again. It just made sense for me to experiment.”
An experiment is what it is, and a dog cannot consent to one. “My dog isn’t going to look at me after a BPC-157 shot and say, ‘Thank you, Dad, that feels good,’” Morelli said. “All you can do is really watch and see him limping less, breathing less heavy, more vibrant and full of energy.” He started at 500 micrograms of BPC-157, scaled from his own experience to Choo’s weight, and raised it gradually to 2 milligrams after seeing no side effects — bearing in mind that no dosage for dogs has ever been established as safe or effective. Around week two or three, he said, Choo was running again and finishing his half-mile walks.
In July the niche went wide. Podcaster Andrew Huberman told his 1.8 million followers on X that he was hearing from “many people” getting “amazing results” with BPC-157 in aging and injured dogs. Morelli said interest surged overnight. His following exploded; he now runs a canine-longevity brand, Pawgen, which sells BPC-157, spends hours a day fielding questions online, and is promoting a Choo Choo meme coin — a “meme with meaning” — to fund a pet rescue he and his wife hope to open.
The cancer question
Dr. Leilani Alvarez, a senior veterinarian at the Schwarzman Animal Medical Center in New York, says clients now ask her about unapproved peptides. She is open to cheaper emerging therapies where evidence exists — stem-cell therapy, massage — but “BPC 157 is one I would be very cautious to use,” she told Business Insider. What happens when a dog takes it for years? How does anyone predict each dog’s immune reaction? She wants controlled clinical trial data first. “Being innovative also means being rigorous,” she said. “Before recommending a treatment, I want to know that it is safe and that it actually improves pain, mobility, healing, or quality of life in my patients.”
The largest unanswered question concerns cancer. BPC-157 appears to stimulate the growth of blood vessels — useful in wound healing, but some researchers worry the same mechanism could feed tumors in dogs that have cancer, or conceivably promote new growths. No good long-term clinical studies settle it. Morelli says he is clear-eyed about gray-market risks, including contaminated or fake products. Celine Halioua, founder and CEO of Loyal, a startup developing longevity drugs for dogs, has called the cancer possibility a “dealbreaker” — though she added that anyone determined to try should work with a vet to watch for “invisible side effects,” use a “reputable” manufacturer, and that “we need better OA [osteoarthritis] drugs for dogs.”
The reversed order of testing
Ordinarily, experimental drugs pass through animal testing before any human swallows them. The peptide boom inverted the sequence: the owners tested themselves first. Samluk heard of the compounds through friends and online forums, took them himself, and reasoned, when Finley was hurt, that the same substances might mend her — cheaply. “If I’m happy to put them in my own body, I’m happy to give them to my dog,” he said. His chosen combination was KPV, marketed as an inflammation control, and BPC-157, short for “body protection compound.” Both were recently shortlisted by an FDA advisory committee to be allowed for compounding in the United States; neither is approved, and there is no recommended veterinary dose. Samluk scaled Finley’s dose from published human amounts, buys from the vendors who first supplied him, and holds affiliate arrangements with some of them — arrangements, he said, that have earned him less than $50.
Veterinary diagnostics and pharmaceutical arthritis shots are real, regulated and costly. The gray market is none of those things; that is its entire appeal. Somewhere in Dallas, Finley is being dosed from vials bought on word of mouth, by an owner who likes to say he consented for two.