BPC-157 has six small human reports and TB-500 none of its own; both were tested on tendons only in rats. Neither is FDA-approved, and both are banned in sport as of October 2026.
For a tendon, the only head‑to‑head data is one 2026 study of 32 rats: TB‑500 gave stronger repaired Achilles tendons than no treatment, BPC‑157 also helped but not by a statistically clear margin, and giving both added nothing. In people, BPC‑157 has six small reports, none of them a controlled injury trial, and TB‑500 has never been tested on its own. For the gut, BPC‑157 is the only one of the two with research, from rats and one colitis enema trial that did not clearly beat placebo.
Every claim on this page is labeled by what was tested: in people, in animals or cells, or a regulatory fact. How we grade evidence: editorial policy.
| Item | BPC‑157 | TB‑500 |
|---|---|---|
| What it is | Lab-made 15-amino-acid fragment of a protein found in human gastric juice | Lab-made 7-amino-acid fragment of thymosin beta-4 (positions 17 to 23) with an acetyl cap |
| Tested in people for | Ulcerative colitis, knee pain, interstitial cystitis and IV safety, in small studies | Nothing yet; one heart-disease trial began recruiting in 2026 |
| Evidence label | Tested in people (tiny, mostly uncontrolled); healing data in rats | Tested in animals or cells only |
| FDA status | Not approved; cannot be compounded; advisory vote 8-6 in favor | Not approved; cannot be compounded; advisory vote 8-6 in favor |
| WADA 2026 | Banned at all times, named under S0 | Banned at all times, named under S2 |
| Last checked | October 15, 2026 | October 15, 2026 |
New trials, FDA changes and side-effect reports, written in plain English. Every result says whether it was tested in people or in animals.
Each row names its evidence type. Every study named here is linked in the sources list at the bottom of the page.
| BPC-157 | TB-500 | Evidence type | |
|---|---|---|---|
| Largest human study | 53 adults with ulcerative colitis, BPC-157 enema vs placebo, published only as a meeting abstract (Ruenzi, 2005) | None. FDA's 2026 review found no study in which TB-500 was given to a person | Tested in people |
| Placebo-controlled result in people | Colitis scores fell 3.2 points on BPC-157 and 1.6 on placebo; FDA found the gap was not statistically clear | No placebo-controlled trial has reported results | Tested in people |
| Same rat tendon study, 2026 | Repaired Achilles tendons trended stronger and healthier than untreated ones, without a statistically clear margin | Repaired Achilles tendons held more load and scored better on two tissue scales than untreated ones | Tested in animals or cells |
| Other animal healing work | 35 preclinical studies on muscle, tendon, ligament and bone injuries, counted by a 2025 systematic review | FDA found no animal study showing the fragment heals wounds; most animal data used full-length thymosin beta-4 | Tested in animals or cells |
| In cell tests | Made rat tendon cells migrate faster and survive oxidative stress (Chang, 2011) | Did not speed wound closure in fibroblasts; one breakdown fragment, Ac-LKKTE, did (Rahaman, 2024) | Tested in animals or cells |
| How it is thought to work | No confirmed receptor; FDA wrote in 2026 that its molecular targets have not been identified | Its parent protein binds actin, which cells need to move; not shown for the fragment in a living body | Tested in animals or cells |
| How long it lasts | Half-life under 30 minutes in animal studies; never measured in people | Never measured in people; a breakdown fragment, Ac-LKK, was found in rat urine up to 72 hours | Tested in animals or cells |
| Side effects seen in people | Headache and flatulence in the healthy-volunteer enema study, with no obvious difference from placebo | None characterized; no human study exists, and FDA's adverse event search found no TB-500 reports | Tested in people |
| Registered trials, October 2026 | Two registered: hamstring strain against placebo (120 people, China, recruiting) and rotator cuff surgery against no treatment (30 people, US, not yet recruiting) | One: heart disease blood markers (80 people, China, recruiting) | Regulatory fact |
| Sport (WADA 2026) | Named under S0, non-approved substances; banned in and out of competition | Named under S2 growth factors as a thymosin beta-4 derivative; banned in and out of competition | Regulatory fact |
| US status, October 2026 | Not approved. Advisory committee voted 8-6 for compounding after FDA reviewed it for ulcerative colitis; no FDA rule | Not approved. A separate vote, also 8-6, after FDA reviewed it for wound healing; no FDA rule | Regulatory fact |
They are unrelated molecules with different evidence. BPC-157 is a 15-amino-acid piece of a stomach protein and has six small human reports. TB-500 is a 7-amino-acid piece of thymosin beta-4 and has none of its own.
BPC-157 was first described in 1993 by a group at the University of Zagreb in Croatia, as a fragment of a protein found in human gastric juice. Its rat studies cover cut tendons, gut ulcers and colitis. FDA reviewers wrote in 2026 that its molecular targets have not been identified (tested in animals or cells).
TB-500 is the seven amino acids at positions 17 to 23 of thymosin beta-4, the part of that protein tied to actin binding, with an acetyl group added to the front. A Belgian anti-doping lab confirmed in 2012 that products sold as TB-500 contain this fragment (Esposito, 2012). FDA's 2026 review states that TB-500 and thymosin beta-4 are not the same substance, so trials of the full protein say nothing direct about TB-500.
Neither has been tested on a tendon in people. In the one rat study that tested both, TB-500 gave the stronger repaired Achilles tendon.
Tested in animals: in a 2026 Turkish study, 32 rats had an Achilles tendon cut and stitched, then got BPC-157, TB-500, both, or nothing for four weeks, 8 rats per group. Tendons from the TB-500 group held more load before breaking than untreated tendons and scored better on two tissue-damage scales. The BPC-157 group's scores also improved, but its totals were not clearly different from untreated rats. Rats given both did no better than rats given either one (Biçer, 2026). The authors call the results preliminary.
Tested in animals: BPC-157 has the longer rat record. In a 2003 study, rats with a cut Achilles tendon given BPC-157 had stronger tendons, better walking scores and smaller gaps over 14 days than rats given saline (Staresinic, 2003). In rat tendon cells it made the cells migrate faster (Chang, 2011). A 2025 systematic review counted 35 preclinical studies of BPC-157 in muscle, tendon, ligament and bone injuries, and found no human safety data (Vasireddi, 2025).
Tested in people: no results yet for either. The first placebo-controlled BPC-157 injury trial, 120 people with hamstring strains in China, started recruiting in February 2026. No TB-500 injury trial is registered.
BPC-157 has been, in six small reports, none of them a controlled trial for an injury. TB-500 has not: FDA searched in 2026 and found no study that gave it to a person.
Tested in people: the only placebo-controlled BPC-157 studies are two enema trials run by the drug company Pliva and published only as meeting abstracts. In 32 healthy men, 24 got BPC-157 and 8 got placebo, and headache and flatulence were the most common complaints in both groups. In 53 people with mild to moderate ulcerative colitis, disease scores fell 3.2 points on BPC-157 and 1.6 on placebo, a gap FDA judged not statistically clear (Ruenzi, 2005, as summarized by FDA).
Tested in people: the other three come from one Florida clinic and had no control group: 16 knee pain patients surveyed by phone, 12 women with interstitial cystitis, and 2 healthy adults given IV infusions (Lee, 2021, 2024 and 2025).
The human trials often quoted for TB-500 used full-length thymosin beta-4, a different molecule. In a 40-person IV safety study in healthy adults (four groups of 10, each with some people on placebo) there were no serious side effects over 14 days (Ruff, 2010), and a 72-person dry-eye trial of thymosin beta-4 eye drops missed both of its main goals (Sosne, 2015). A TB-500 trial in 80 people with heart disease began recruiting in China in 2026.
No published human study. FDA searched in 2026 and found none.
Patients Healthy volunteers. Tested in people. Only the two enema studies had a placebo group, and both were published only as meeting abstracts.
No study in people has tested the pair. In the one rat study that tried it, giving both healed tendons no better than either one alone.
The only human data is 4 knee patients in the uncontrolled Florida survey who got BPC-157 plus thymosin beta-4, form not stated; 3 reported relief (Lee, 2021). FDA's adverse event database holds one report of a woman whose skin and gums darkened after injecting a research-label product containing both, and the darkening came back when she used it again. Which peptide caused it is unknown (FDA, 2026).
Neither is FDA-approved, and as of October 2026 neither can be legally compounded by a US pharmacy. An FDA advisory committee voted 8-6 in favor of both in July 2026, but FDA has not acted.
Every peptide's FDA, compounding and WADA status in one place: are peptides legal in the US.
These are the questions the published studies of both drugs leave open.
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