BPC-157 vs TB-500: what the human evidence actually is, side by side

BPC-157 has a small human record of its own: three published reports covering about 30 people, all uncontrolled. TB-500, the seven-amino-acid fragment of thymosin beta-4, has no published human trial yet, though full-length thymosin beta-4 has randomised trials, mostly as eye drops. Neither has a controlled trial in the tendon, muscle or joint injuries they are most often discussed for.

People ask about the two together because they are sold side by side and are often described as if they were one product. They are different molecules with different evidence. This piece lays the human evidence next to each other and shows where it is missing. We cover each in depth in our BPC-157 guide and TB-500 and thymosin beta-4 guide.

Are BPC-157 and TB-500 the same thing?

No. BPC-157 is a chain of 15 amino acids. TB-500 is a synthetic version of a seven-amino-acid stretch of thymosin beta-4, a 43-amino-acid protein found in most tissues [7]. A 2003 cell study from the US National Institutes of Health found that this stretch drove blood-vessel cell migration in dishes at about the same potency as the whole protein [7]. That is a laboratory finding, and it is the scientific reason the fragment exists.

The practical consequence is that human results for one cannot be read across to the other. Trials of thymosin beta-4 tested the full protein. They did not test the fragment.

What the human evidence for BPC-157 is

BPC-157 has three small published human reports, none with a control group. A 2025 systematic review of musculoskeletal BPC-157 research screened 544 articles and kept 36: 35 preclinical studies and one clinical study [1].

The authors say no specific tools were used to measure function, quality of life or stiffness [2]. The systematic review summarises the same paper differently, as 7 of 12 patients reporting relief for more than six months [1]. We could not reconcile those two readings from the abstracts.

The second report treated 12 women with interstitial cystitis who had not responded to pentosan polysulfate. Ten reported complete resolution and two reported 80% improvement on a global response questionnaire, with no adverse events recorded. The product came from a compounding pharmacy and was injected once, 10 mg in total [3]. The third gave two adults an intravenous infusion of 10 mg and then 20 mg over two days, with no measurable change in heart, liver, kidney, thyroid or glucose markers and no side effects reported. Both had used intravenous BPC-157 before [4].

All three come from the same lead author, in the same journal. A Phase 2 randomised trial in acute hamstring strain, with a planned 120 participants and MRI and return-to-sport outcomes, is recruiting and has no results [5]. A 2015 Phase 1 oral-tablet trial registered 42 volunteers and still has no posted results [6].

What the human evidence for TB-500 is

For the TB-500 fragment itself, the published human record is empty so far. Its first registered trial is a Phase 1/2 study of up to about 80 adults with stable atherosclerotic cardiovascular disease, with adverse events as the primary outcomes. It began recruiting in February 2026 and has no results [14].

The human trials that do exist used full-length thymosin beta-4:

• Healthy volunteers. Forty people in four cohorts received intravenous thymosin beta-4 or placebo, then daily doses for 14 days. Adverse events were infrequent and mild or moderate, with no dose-limiting toxicity [8].
• Venous leg ulcers. A Phase 2 trial randomised 73 people to topical thymosin beta-4 or placebo. Safety was comparable to placebo, and the authors said one dose "may have the potential" to accelerate healing [9].
• Dry eye. A 72-person Phase 2 trial missed both primary endpoints [10]. The two large Phase 3 trials, ARISE-2 (601 people) and ARISE-3 (700), have posted results on ClinicalTrials.gov showing near-identical changes on drops and placebo for their primary measures [12,13]. We could not find peer-reviewed publications of either.
• Neurotrophic keratopathy. In an 18-person Phase 3 trial of eye drops, complete corneal healing at four weeks occurred in 6 of 10 treated against 1 of 8 on placebo (p = 0.0656). That just missed the usual significance threshold. Sponsor employees helped design the study [11].

Everything in that list tested thymosin beta-4 applied to the surface of an eye or skin, or given into a vein in healthy volunteers. None tested an injected fragment for an injury.

BPC-157 and TB-500 compared

What the animal work adds

Animal data fill the gap, and they should be read as animal data. In a 2026 four-group rat study, TB-500 improved the load an Achilles tendon could bear before failing and tissue scores at four weeks. BPC-157 alone did not reach significance on those measures, and the combination added nothing beyond either peptide alone [15]. The study used 32 rats, eight per group. We cover it in our piece on combining the two.

Regulatory status

Neither is approved as a medicine in the UK or by the US FDA in anything we found. In the UK, whether either counts as a medicinal product depends on how it is presented and what it does, which the MHRA decides case by case, and we found no published MHRA determination on either one. Our article on how the MHRA and UK law treat peptides sets out the legal test. It is not legal advice.

In the US, the FDA's compounding safety page lists BPC-157 as having "no, or only limited, safety-related information for the proposed routes of administration". For the TB-500 fragment, it says it has "not identified any human exposure data" [16].

What is still open

• Whether BPC-157 does anything measurable against a control in a tendon, muscle or joint injury. The hamstring trial [5] is the first registered test.
• What the TB-500 fragment does in people at all.
• Whether the full-length thymosin beta-4 trial results apply to an injected fragment. They are different molecules and routes.
• Whether the two interact. The only direct test is the rat study [15].
• Long-term safety of either, by any route.

What this means

Our position is that these are not two versions of the same thing, and the useful way to compare them is by what has been tested. BPC-157 has a thin but real human record of its own, with no control group and one source. TB-500 has a well-studied relative in full-length thymosin beta-4, whose largest trials were flat on their main eye outcomes and whose one encouraging result sits in a rare corneal condition. The fragment has no human results yet.

That asymmetry matters when a seller or an influencer talks about them as a pair. Evidence for the protein does not transfer to the fragment, and a handful of uncontrolled reports on BPC-157 do not transfer to a combination. The one direct comparison we found is in rats [15].

Both questions can be answered, and the Phase 2 hamstring trial and the Phase 1/2 heart-disease safety trial are the first steps [5,14]. Until they report, we would treat any confident claim about either compound's effect on an injury in people as ahead of the published evidence. Nothing here is a recommendation to use either, and both are prohibited in sport [17].

What readers report

First-hand accounts, shared with permission. They are self-reported, not evidence, and sit alongside the research above rather than in place of it.

Educational content only — not medical advice. Many peptides discussed on HPR are not approved for human use. Talk to a qualified clinician before making any decision about your health.