BPC-157 vs TB-500: Different Peptides, Thin Evidence and Lab Results

BPC-157 and TB-500 are not variations of the same thing. BPC-157 is a 15-amino-acid peptide first described from gastric juice, and TB-500 is a seven-amino-acid fragment of thymosin beta-4, a protein found throughout the body. Both are sold for tendon, muscle and general tissue repair, and for both the evidence comes overwhelmingly from cells and animals. Neither is an FDA-approved drug: we found no approved product for either in DailyMed, and FDA's bulk drug substances page, current as of April 22, 2026, lists both only under nominations that were withdrawn. No human trial has compared them.

At a glance

How they work differently

The two are unrelated in structure and in the story told about them.

BPC-157 is described as a partial sequence of a larger protein from human gastric juice. A 2025 systematic review of the orthopedic literature reports that, in preclinical work, it increases growth hormone receptor expression, acts on pathways involved in cell growth and new blood vessel formation, and lowers inflammatory signals (Vasireddi et al., HSS Journal, 2025). That is a description of cells and rodents, not people.

TB-500 is sold as the actin-binding stretch of thymosin beta-4. Analytical chemists identified that acetylated fragment (Ac-LKKTETQ) in a product suspected of being used for doping (Esposito et al., Drug Testing and Analysis, 2012). The parent protein is the major actin-sequestering molecule in cells, with a well-studied role in cell migration and wound repair (Goldstein et al., Trends in Molecular Medicine, 2005). Whether the fragment does what the whole protein does is the open question. A 2024 study measured TB-500 and its breakdown products and tested them on fibroblasts in a dish: the parent TB-500 showed no significant wound-healing effect, while one breakdown product did, leading the authors to suggest that wound-healing activity attributed to TB-500 may belong to that metabolite (Rahaman et al., Journal of Chromatography B, 2024).

What the evidence shows

Head-to-head: no human trial exists

We found no human study that compared BPC-157 with TB-500, and none that tested them together. Comparing numbers from separate studies would not be reliable, because the species, injuries and outcome measures differ.

The one animal study that tested both

A 2026 rat study did test them side by side. Thirty-two rats had a surgically transected and repaired Achilles tendon and were split into four groups of eight: untreated, BPC-157, TB-500, and both together, for four weeks. Both peptides were associated with better tendon structure. Only TB-500 reached statistical significance on the mechanical test (the load the healed tendon could bear before failing), and the BPC-157 group showed numerically better but not statistically significant scores on the tendon-quality scoring. The combination did not give additional benefit over either peptide alone (Biçer et al., Joint Diseases and Related Surgery, 2026). The authors call the study exploratory. It is 32 rats, one injury, one time point, and it says nothing direct about people.

So the only head-to-head data is a small rat experiment where TB-500 looked stronger on the mechanical test and the pairing added nothing. That is not evidence about people, and one study is not a verdict.

BPC-157 on its own

The animal literature is large: accelerated healing across tendon, ligament, muscle and bone models in preclinical studies. In humans, a 2025 narrative review counted three published studies and no controlled efficacy trial (McGuire et al., Current Reviews in Musculoskeletal Medicine, 2025). They are a retrospective review of 17 patients who received knee injections (16 were reached by phone, four of them given BPC-157 with thymosin beta-4), in which 14 of the 16 reported significant pain relief, with no control group (Lee and Padgett, 2021); a 12-woman pilot for interstitial cystitis where all reported improvement (Lee and Walker, 2024); and a two-person intravenous safety pilot with no adverse effects or biomarker changes (Lee and Burgess, 2025). Those designs cannot separate a drug effect from placebo or natural recovery. Our BPC-157 guide walks through it.

TB-500 on its own

For the fragment sold as TB-500, we found no published human study of any kind. The human trials in this area used the full-length thymosin beta-4 protein in investigational formulations. One example is a small placebo-controlled phase III eye trial, where complete corneal healing occurred in 6 of 10 treated patients versus 1 of 8 on placebo, a strong trend that did not reach conventional statistical significance (p = 0.0656) (Sosne et al., Int J Mol Sci, 2022). That is a different, larger molecule than the one in a TB-500 vial. See our TB-500 guide.

Side effects and risks compared

Neither has meaningful human safety data. For BPC-157 it amounts to two people who each received two intravenous infusions on consecutive days, plus small uncontrolled reports; the narrative review notes the three human studies reported no adverse effects, but they were far too small to rule anything out. For the TB-500 fragment there is nothing published in humans.

Both share a theoretical worry: a compound that encourages new blood vessel growth could, in principle, help a tumor. For BPC-157, the narrative review notes the concern about pathologic angiogenesis and also cites lab work suggesting it can inhibit tumor-related growth signals, so the question is open. For thymosin beta-4, a 2003 mouse-melanoma study found that cells engineered to make more of it formed bigger tumors and metastasized more (Cha et al., JNCI, 2003). That is a study of the parent protein in mice, not of the TB-500 fragment in people.

The regulatory picture changed this year. On April 15, 2026 FDA announced it would remove both from Category 2 of its interim compounding list within seven days, after the nominations were withdrawn (Frier Levitt, April 2026; FDA bulk drug substances page, updated April 22, 2026). The FDA page still says it has identified no or only limited safety information for BPC-157 for the proposed routes, and no human exposure data for TB-500. In July 2026 FDA's Pharmacy Compounding Advisory Committee voted to recommend adding both, with KPV, MOTS-c, Epitalon and Semax, to the 503A bulks list; the vote is non-binding, HHS must approve, and pharmacies cannot compound them until final rulemaking (NCPA, July 31, 2026). BPC-157 is also prohibited under the S0 category of the WADA Prohibited List (USADA).

What the lab tests show for each

As of September 30, 2026, our database holds 41 BPC-157 vials from 14 vendors (31 lab reports, November 2024 to August 2026). Median purity was 99.57%; 33 of 38 vials with a purity result were at 99% or better and 2 were under 95%. On fill amount, the median measured amount ran 17.8% over label, 2 of 34 vials were within 5% of label (9 were within 10% as of September 30, 2026), 13 measured more than 20% over and 1 more than 50% over. 3 of the 41 vials failed our definition (empty, under 95% pure, more than 20% under label or more than 50% over), 7.3%.

For TB-500 there are 22 vials from 8 vendors (20 reports, November 2024 to February 2026). Median purity was 99.55%, with 18 of 19 measured vials at 99% or better. The median amount was 9.0% over label, with 2 of 22 within 5%, and 3 more than 20% over. As of September 30, 2026, 12 were within 10% and none had failed.

The samples differ in size (41 vials versus 22, and different date ranges), and a single vendor with several vials can move either set. They cannot rank the two compounds against each other. What they do show is that overfill, not low purity, is the pattern in both.

Here is who has the strongest independent lab record for BPC-157 right now:

And for TB-500:

Buying smarter

Check each vendor's record for the specific compound on the BPC-157 results page and the TB-500 results page, and look at how many reports sit behind a score and how recent they are. Treat a posted COA as a starting point; see how to read a peptide COA and fake peptide COAs. Because overfill is the pattern here, a quantity test on your own vial tells you more than a purity retest, and how to get a peptide tested covers ordering one. If a report comes back bad, stop using that batch, tell anyone who bought from the same run, bring it to the vendor, and submit it to VendorVerify.

Database figures without a date update automatically from VendorVerify's lab results; dated figures are snapshots. This isn't medical advice; both compounds are sold for research use only and neither has been approved by FDA.