BPC-157 Research: What the Animal Studies Show and What Is Still Missing

LynxLab · 24 October 2026 · 8 min read

What the BPC-157 studies from Zagreb found in rat tendon, ligament and gut models, who ran them, and why controlled human trial data is still almost absent.

Photo: Kylie Anderson, Unsplash

Most of what is written about BPC-157 online traces back to one laboratory. The pharmacology department at the University of Zagreb, led by Predrag Sikiric, has published on the peptide since 1993, and nearly every positive headline comes from its rat models. This post sets out what those studies measured, which findings have been checked by anyone else, and how thin the human evidence is as of October 2026.

Where BPC-157 came from

In 1993 Sikiric and colleagues described "a new gastric juice peptide" in the Journal of Physiology Paris. They reported a parent protein of about 40,000 molecular weight isolated from human gastric juice, and a 15 amino acid fragment, which they called BPC 157, that they believed carried its activity (Sikiric et al., J Physiol Paris 1993).

The same paper framed the stomach as an organ that starts a protective response to stress, and proposed BPC as a mediator of that response. The group reported effects in several species at microgram and nanogram per kilogram doses, given by injection into the abdomen or directly into the stomach.

That paper set the pattern for the next three decades: a broad protective claim, very small doses, and the peptide given alone without a carrier. The bpc-157 sold today is a synthetic copy of that 15 amino acid sequence.

The tendon studies: a cut rat Achilles

The best known result is the 2003 Achilles tendon paper. Staresinic, Sikiric and 16 co-authors cut the right Achilles tendon of rats 5mm above the heel bone, then gave BPC 157 at 10 micrograms, 10 nanograms or 10 picograms per kilogram by intraperitoneal injection once a day (Staresinic et al., J Orthop Res 2003).

Treated rats were assessed on days 1, 4, 7, 10 and 14. The paper reports higher load to failure, a higher Achilles functional index, more fibroblasts and collagen under the microscope, and a smaller tendon gap than in saline controls.

A follow-up in 2006 looked at the harder problem of tendon torn away from bone. Krivic and colleagues detached the Achilles from the calcaneus and reported that the peptide improved tendon-to-bone healing over 21 days, and partly reversed the damage done by the corticosteroid 6alpha-methylprednisolone (Krivic et al., J Orthop Res 2006).

Both are rat studies with daily injections starting 30 minutes after surgery. Anyone reading them as evidence about bpc 157 in people is reading something the authors did not test.

Ligament and muscle: the 90-day MCL study

In 2010 Cerovecki and colleagues at the University Hospital of Traumatology in Zagreb transected the medial collateral ligament of the rat knee and followed healing for 90 days (Cerovecki et al., J Orthop Res 2010).

The routes are what make this study interesting. The peptide was given by intraperitoneal injection at 10 micrograms or 10 nanograms per kilogram, as a thin cream on the injury, and in the drinking water at 0.16 micrograms per millilitre. The authors reported functional, biomechanical and histological improvement with all three.

The drinking water result is often quoted by people selling oral products. It is one rat ligament study, from the same group, and we could not find an independent replication in PubMed.

Has anyone outside Zagreb reproduced the findings?

One group has, in cell culture. Chang, Pang and colleagues at Chang Gung University in Taiwan grew tendon fibroblasts from rat Achilles explants and found that BPC 157 sped up outgrowth from the explant, improved survival under hydrogen peroxide stress and increased migration in a dose-dependent manner (Chang et al., J Appl Physiol 2011).

The Taiwan paper did not find that the peptide made fibroblasts divide faster. The effect was on movement and survival, which the authors tied to the FAK-paxillin pathway.

A 2025 systematic review from Case Western Reserve University searched PubMed, Cochrane and Embase up to June 2024 and found 544 articles, of which 36 met its criteria: 35 preclinical and one clinical (Vasireddi et al., HSS Journal 2025). An investigation by Undark, co-published by STAT in February 2026, put it more bluntly: almost all the data comes from a single Croatian group, and the roughly 200 BPC-157 studies on PubMed mostly carry Sikiric or Sven Seiwerth as an author (Talpos, STAT 2026).

The same investigation reported that Sikiric is named on BPC-157 patent applications dating back to 1989 and is listed as an owner of PharmaCotherapia, the company that sponsored a 2015 trial, and that these interests were not disclosed on the papers it reviewed. A lab weighing up research-grade bpc-157 for its own work should read the Zagreb papers with that in mind.

The gut trials that were never published

BPC-157 began life as an anti-ulcer candidate. The 2003 and 2006 orthopaedic papers both describe it as being "in clinical trials for inflammatory bowel disease" under the codes PLD-116 and PL 14736 at the Croatian company Pliva.

Those trials are the missing piece. STAT reported that the two Pliva ulcerative colitis trials from the 2000s do not appear in PubMed or other major databases, and that it is not clear they were ever published in a peer-reviewed journal.

A 2015 phase 1 study of oral BPC-157 tablets, registered as NCT02637284 by PharmaCotherapia and planned for a hospital in Tijuana, listed 42 healthy volunteers. Its record on ClinicalTrials.gov has not been updated since December 2015 and no results are posted (NCT02637284, ClinicalTrials.gov).

For anyone deciding whether to buy bpc-157 for a gastrointestinal research project, this is the honest summary: the gut claim is the oldest and the least documented in public.

What the human data actually amounts to

The 2025 narrative review by Flynn McGuire and colleagues at the University of Utah counted three pilot studies in humans: an intra-articular knee pain series, an interstitial cystitis series and an intravenous safety and pharmacokinetics study. None had a control group (McGuire et al., Curr Rev Musculoskelet Med 2025).

The knee series is the one most often cited. In the Case Western review's description, 7 of 12 patients with chronic knee pain reported relief for more than six months after a single injection. It was retrospective and uncontrolled.

McGuire's conclusion was that BPC-157 "should be considered investigational" until well-designed trials exist. Asked by Undark, he was blunter and said it should not be used by humans.

The mechanisms proposed in rats, including VEGFR2 activation and nitric oxide signalling through the Akt-eNOS pathway, have not been tested in a controlled human study. That is the gap any lab buying bpc-157 for research is working in.

Trials registered in 2026

Two registrations are worth watching. Hudson Biotech registered a randomised, double-blind, placebo-controlled phase 2 trial of daily subcutaneous BPC 157 for 14 days in 120 people with an MRI-confirmed grade II hamstring strain. It began recruiting at Peking University Shenzhen Hospital in February 2026, with primary completion estimated for February 2027 (NCT07437547, ClinicalTrials.gov).

The University of Arkansas posted a 30-person phase 1 pilot in September 2026 looking at tendon healing after rotator cuff repair, due to start in January 2027. Its registration states that the peptide "has not yet been studied in formal human clinical trials".

If either reports, it will be the first controlled human data in more than 30 years of publication. Until then the research record is rat tendon, rat ligament, rat gut and one Taiwanese cell culture series.

The regulatory consequences of that gap are covered in our post on BPC-157 legal status in the UK, WADA and the FDA, and the chemistry behind the "stable gastric" label in why BPC-157 is called the stable gastric pentadecapeptide.

LynxLab stocks BPC-157 for research use in 5mg, 10mg and 20mg vials from £16.95, tested to 99% purity with the certificate of analysis on the product page.

Frequently asked questions

Has BPC-157 been tested in humans?

Barely. A 2025 University of Utah review found three small pilot studies, none controlled, and two Pliva ulcerative colitis trials from the 2000s were never published in an indexed journal. A placebo-controlled phase 2 hamstring trial began recruiting in China in February 2026.

Who discovered BPC-157?

Predrag Sikiric's pharmacology group at the University of Zagreb described it in 1993 as a 15 amino acid fragment of a larger protein found in human gastric juice. The same group has written most of the roughly 200 papers on it since.

What did the BPC-157 tendon studies find?

In rats with a cut Achilles tendon, daily injections were linked to higher load to failure, better function scores and more collagen by day 14 (Staresinic et al., 2003). A 2006 study reported similar effects for tendon torn from bone. Neither has been repeated in people.

Is any BPC-157 study independent of the Zagreb group?

A Taiwanese team at Chang Gung University showed in 2011 that the peptide increased migration and survival of rat tendon fibroblasts in culture. Reviews from Utah, Case Western and a Polish group in 2025 assessed the literature but ran no new experiments, so labs sourcing bpc-157 uk stock for replication work are entering a thin field.

Sources

Research use only

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