Combination review

BPC-157 and TB-500: What the Evidence Shows

These two are sold together more often than separately. The case for pairing them rests on a claim that does not survive checking: that TB-500 is thymosin beta-4. It is not.

  • 7Amino acids in TB-500, taken from a protein that has 43
  • NoneRegistered trials testing the two compounds together
  • Category 2The FDA compounding list that both compounds sit on
  • BothAre prohibited in tested sport at all times, in and out of competition

The short version

No study has tested BPC-157 and TB-500 together in people. Neither has been shown to work on its own in a completed human trial. Combining two compounds that are individually unproven does not produce evidence for the pair — it produces two unknowns interacting in a way nobody has measured.

There is also a specific factual problem with how TB-500 is marketed, and it is the most useful thing on this page. Sellers routinely point to clinical trials of thymosin beta-4 as evidence for TB-500. Those trials studied a different molecule.

TB-500 is not thymosin beta-4

Thymosin beta-4 is a naturally occurring protein, 43 amino acids long, and it has a genuine clinical development history. TB-500 is a synthetic fragment of it. The FDA identifies the substance on its compounding list by sequence, which removes any ambiguity about what is being discussed:

How the FDA names it

“Thymosin beta-4, fragment (LKKTETQ), also known as TB-500”

LKKTETQ is seven amino acids. It corresponds to residues 17 to 23 of thymosin beta-4, which is how the trial registry describes it as well: the one study testing TB-500 by name calls it the “Thymosin Beta 4 17-23 Fragment.” So the marketed compound is roughly a sixth of the protein whose research record is used to sell it.

Worth knowing

A fragment is not a smaller dose of the whole. It is a different molecule, and it has to earn its own evidence. Findings about thymosin beta-4 do not transfer to TB-500 simply because one sequence appears inside the other.

This is the same failure we documented with BPC-157 itself, where more than one substance is sold under a single common name, and with compounded semaglutide, where the FDA reported salt forms it describes as different active ingredients from the approved drug. In each case a name is doing work that the chemistry does not support.

What the thymosin beta-4 trials actually studied

The full-length protein has been through a real clinical programme. Searching the registry for thymosin beta-4 and TB-500 together returns 18 registered studies. Several reached Phase 3, and two Phase 1 studies in healthy volunteers completed. On its own terms that is a substantial record, and far more than BPC-157 has.

The question is what those studies were for. The Phase 3 work is ophthalmic — dry eye syndrome and neurotrophic keratopathy, delivered as eye drops. The rest cluster around acute myocardial infarction, corneal wounds, pressure ulcers, venous stasis ulcers and epidermolysis bullosa. Two of the wound-healing studies were terminated.

The gap

Not one of those 18 studies tested tendon, ligament or muscle repair — the reason people buy TB-500. The clinical record belongs to a different molecule and, separately, to entirely different conditions.

So an argument that runs “TB-500 is well studied, it reached Phase 3” fails twice over. The Phase 3 trials used a different compound, and they studied eyes.

What the FDA says about TB-500

TB-500 sits alongside BPC-157 on the FDA’s Category 2 list, for bulk drug substances the agency says may present significant safety risks in compounding. Its entry is worth quoting because it is not identical to the BPC-157 one.

What the FDA says

“Compounded drugs containing thymosin Beta-4, Fragment (LKKTETQ) may pose risk for immunogenicity for certain routes of administration due to the potential for aggregation as well as peptide-related impurities. FDA has not identified any human exposure data drug products containing Thymosin Beta-4, Fragment.”

Two things separate this from the BPC-157 entry. The FDA names aggregation specifically — peptide molecules clumping together, which is one of the recognised ways a peptide provokes an immune response it otherwise would not. And where BPC-157 is described as having “no, or only limited” safety information, TB-500 is described as having no identified human exposure data at all. That is the flatter of the two statements.

The agency’s conclusion is that it “lacks important information regarding any safety issues raised by this drug, including whether it would cause harm if administered to humans.”

The evidence for the combination

There is none we could find. No registered trial tests BPC-157 and TB-500 together, in any population, for any indication. The rationale offered for pairing them is mechanistic: the two are said to act on different parts of the repair process, so combining them should do more than either alone.

That reasoning is not absurd, and combination therapy is a real strategy in medicine. But it is reasoning, not evidence, and it carries a specific hazard. Combinations are tested separately from their components precisely because effects are not additive by default — they can cancel, or interact in ways neither compound produces alone. Nobody has run that test here.

Worth knowing

A blend also compounds the identity problem. If it is unresolved what is in a vial of one of these peptides, a vial containing two of them carries the same question twice, plus a new one about the ratio.

Blends sold with further additions — and several are marketed with a third or fourth peptide included — extend that problem rather than solving it. Each added component is another substance with its own characterisation questions and its own absent human data.

Both compounds entered human trials in the same week

This is a detail worth recording rather than interpreting. In February 2026 two trials began: a Phase 2 of BPC-157 for acute hamstring strain, and a Phase 1/2 of TB-500 for cardiovascular biomarkers. They started three days apart, on 2 and 5 February. Both are sponsored by Hudson Biotech. Both are running at Peking University Shenzhen Hospital. Both are scheduled to complete on 17 February 2028.

So the first serious human testing of both compounds is being conducted by one company at one hospital. We are not suggesting anything improper about that; a single sponsor deciding to develop two related compounds in parallel is ordinary. It is worth knowing because it means the near-term evidence base for both will rest on one institution’s work, and independent replication will still be outstanding after 2028.

Note also that the TB-500 trial is not studying healing. Its conditions are atherosclerotic cardiovascular disease and endothelial dysfunction, and its primary outcomes are adverse events. It is a safety and tolerability study, which is the right place to start, and it will not tell anyone whether TB-500 repairs a tendon.

Both are prohibited in tested sport

BPC-157 is prohibited under S0, the World Anti-Doping Agency’s category for substances with no approval from any government health authority for human therapeutic use. TB-500 is prohibited under S2, which covers peptide hormones, growth factors and related substances, and which extends to thymosin beta-4 and its fragments.

Different categories, same practical effect: both are banned at all times, in competition and out of it. There is no period during which either is permitted for a tested athlete, and the ban applies regardless of whether anything was gained. Full detail on the BPC-157 position is on our side effects page, which covers the anti-doping and Department of Defense listings.

What this page will not tell you

Most of what is searched alongside these two compounds concerns how to use them. We do not publish any of it, and the reason is not squeamishness — it is that the information does not exist to publish.

  • Dosing, dosing charts, calculators or protocols for either compound or a blend. No completed human trial has established a dose for either, so every chart in circulation is derived from animal work or from other charts.
  • How to mix, reconstitute, or inject a blend, or how often to do so.
  • Which blend ratios or products are better. We do not review grey-market suppliers, and no independent standard exists to review them against.
  • Whether a combination is right for your injury. We do not employ clinicians and we have never met you.

Sources and method

  • The FDA entry and the sequence. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks, FDA, content current as of 22 April 2026. The LKKTETQ identification and the aggregation and human-exposure language are quoted from that page.
  • The trial record. ClinicalTrials.gov, searched for TB-500 and thymosin beta-4, returning 18 registered studies. The TB-500 trial is NCT07487363, which supplies the 17-23 fragment description; the BPC-157 trial is NCT07437547. Sponsors, sites and dates are read from those records.
  • Prohibited status. The S0 classification for BPC-157 is stated by USADA. The S2 classification for TB-500 follows the World Anti-Doping Agency’s Prohibited List category for peptide hormones, growth factors and related substances.
  • What we could not verify. We have not read the individual thymosin beta-4 trial reports, only their registry entries, so we describe what those studies set out to test rather than what they found. We did not find any registered study of the two compounds combined, but a search of one registry cannot prove that no such study exists anywhere. We have not tested any product or blend.
  • Method. The distinction between thymosin beta-4 and its fragment is drawn from how the FDA and the trial registry name the substances, not from secondary commentary. Where this page reports an absence, we looked for the thing and did not find it.

BPC-157 overview →   BPC-157 side effects →   BPC-157 benefits →

FDA and registry sources checked 30 August 2026. We recheck this page when either February 2026 trial reports.