BPC-157 vs TB-500: differences, evidence and safety

Verdict: BPC-157 is a synthetic 15-amino-acid peptide with three small, uncontrolled human reports. TB-500 is a seven-amino-acid fragment of thymosin beta-4 with no published human data. Neither is FDA-approved, both are prohibited in sport, and nearly all the evidence for either comes from animals.

This comparison of BPC-157 vs TB-500 grades each claim by evidence level, lists the registered human trials, and answers the “Wolverine stack” question with the one controlled study that has tested the pair together: a 2026 rat study in which the combination did not beat either peptide alone [Animal]. This page is not medical advice.

Item	BPC-157	TB-500
US FDA status	Not approved for any use	Not approved for any use
Compounding (503A/503B)	“Nominated but withdrawn” on FDA’s Category 2 page (FDA); not on the 503A bulks list	Same: “nominated but withdrawn”; not on the 503A bulks list
WADA 2026	Prohibited, S0 non-approved substances (USADA)	Prohibited, S2.3 growth factors (WADA)
Strongest evidence	Human, uncontrolled (n=16)	Animal (rat)
Human trials	0 published RCTs; 4 registered: NCT07437547, NCT07803250, NCT02637284, NCT07752381	0 published; 1 registered: NCT07487363
Last checked	2026-09-29	2026-09-29

BPC-157 vs TB-500 at a glance

Feature	BPC-157	TB-500
What it is	Synthetic “gastric pentadecapeptide” (15 amino acids) (Staresinic 2003)	Synthetic, acetylated copy of an active region of thymosin beta-4, LKKTETQ (Ho 2012)
Class	Unapproved investigational peptide	Unapproved peptide fragment
Proposed mechanism	VEGFR2 activation, new blood vessel growth [Animal, Lab]	Actin-binding motif of thymosin beta-4 [Lab]
Main research focus	Tendon, muscle and gut injury in rodents	Wound, tendon, heart repair (mostly the full protein)
Published human studies	3 uncontrolled reports (n=16, 12, 2)	None
Registered human trials	4 (one phase 2 recruiting; one completed supplement study, no results posted)	1 (phase 1/2 recruiting)
FDA approval	None	None
FDA advisory review, July 2026	Nominated for ulcerative colitis	Nominated for wound healing
WADA	S0	S2.3
Routes studied	Rodent intraperitoneal; human IV, knee joint, bladder	Rodent intraperitoneal; no human route studied
Timelines in studies	Rat tendon: 14–28 days	Rat tendon: 28 days
Main safety concerns	Immunogenicity, impurities, no long-term human data	Immunogenicity, aggregation, no human exposure data

Sources for the table rows: Hsieh 2017, Philp 2003, FDA advisory committee page, Biçer 2026, and the studies cited in the sections below.

What is BPC-157?

BPC-157 is a synthetic 15-amino-acid peptide that researchers describe as a “stable gastric pentadecapeptide” (Krivic 2006). A 2025 systematic review of its use in orthopaedic sports medicine found 36 studies: 35 preclinical and one clinical (Vasireddi 2025). Most of its research record is rat studies of tendon, muscle and gut injury. It has no approved use in the US, and FDA says it “lacks sufficient information to know whether the drug would cause harm when administered to humans” (FDA).

What is TB-500?

TB-500 is a synthetic version of one short region of thymosin beta-4 (Tβ4), a natural actin-binding protein. Anti-doping chemists identify it as N-acetylated LKKTETQ (Ho 2012), and a trial registration describes it as the “17-23 fragment” of Tβ4 (NCT07487363). This distinction matters: human trials of full-length Tβ4 exist, but they tested a different molecule. For the fragment itself, FDA says it has “not identified any human exposure data” (FDA).

How do BPC-157 and TB-500 work differently?

The proposed mechanisms come from cell and animal work; none has been confirmed in people.

• BPC-157: in rats with a blocked leg artery and in cultured blood-vessel cells, it increased vessel density and activated VEGFR2, a receptor that drives new blood vessel growth [Animal, Lab] (Hsieh 2017).
  TB-500: its parent protein binds single actin molecules one-to-one, holding them back from forming the filaments cells use to move [Lab] (Safer 1991).
• BPC-157: in rat tendon cells, it sped the outgrowth of tendon explants and increased cell migration, but did not change cell proliferation [Lab] (Chang 2011).
  TB-500: the seven-amino-acid actin-binding motif of Tβ4 showed near-identical activity to the full protein in lab angiogenesis tests using human blood-vessel cells and chick aortic rings [Lab] (Philp 2003).
• Both: each is described as promoting blood vessel growth. That shared property is also the basis of the main theoretical safety question (see below).

Evidence head-to-head

Each cell names the best evidence found for that outcome. “Tβ4” means the full-length parent protein, not TB-500. The site’s method for grading evidence explains the levels.

Outcome	BPC-157	TB-500
Tendon healing	Animal: stronger rat Achilles repair over 14 days (Staresinic 2003)	Animal: higher load to failure at 4 weeks, p<0.05 (Biçer 2026)
Same-study comparison	Animal: strength gain not significant vs control (Biçer 2026)	Animal: significant strength gain vs control (same study)
Knee pain	Human, uncontrolled chart review, n=16 (Lee 2021)	No data
Bladder pain (interstitial cystitis)	Human, uncontrolled pilot, n=12 (Lee 2024)	No data
Skin wounds	Not reviewed in this comparison	Fragment: no data. Tβ4: Animal, faster rat wound closure (Malinda 1999)
Dry eye	No human data	Fragment: no data. Tβ4 eye drops: Human RCT, n=72 (Sosne 2015)
Heart attack recovery	No human data	Fragment: no data. Tβ4: Human RCT, n=96, no overall difference (Zhang 2025)
Human safety	Human, n=2, two IV doses, no adverse effects (Lee 2025)	Fragment: none. Tβ4 IV: Human RCT, n=40, no dose-limiting toxicity (Ruff 2010)

Details behind the human rows:

• BPC-157 knee pain: a one-year chart review at a single US clinic reached 16 patients; 11 of 12 given BPC-157 alone reported significant improvement in knee pain. There was no control group, and the authors list small sample size and mixed diagnoses as limitations [Human, case series, n=16] (Lee 2021).
• BPC-157 interstitial cystitis: 12 women whose symptoms had not responded to standard therapy received BPC-157 into the bladder; 10 reported complete symptom resolution and no adverse events were recorded [Human, uncontrolled pilot, n=12] (Lee 2024).
• BPC-157 safety: two adults received IV BPC-157 on two days with no measurable change in heart, liver, kidney, thyroid or glucose markers [Human, n=2] (Lee 2025). Two people over two days cannot show long-term safety.
• Tβ4 heart attack trial: in 96 randomized patients, infarct size did not differ overall between recombinant Tβ4 and placebo; a subgroup given the first dose within 8 hours of the artery-opening procedure (n=43) had smaller infarcts at 90 days [Human RCT, n=96] (Zhang 2025).
• Tβ4 eye drops: 0.1% drops for 28 days reduced discomfort scores in a controlled dry-eye test by 27% vs placebo, with no adverse events observed [Human RCT, n=72] (Sosne 2015). Larger phase 3 eye-drop trials followed, including ARISE-2 (n=601) and ARISE-3 (n=700).

Which fits which goal?

• BPC-157 has more evidence for human pain outcomes, but only in the weakest form: two uncontrolled reports on knee and bladder pain (Lee 2021, Lee 2024). It also has a larger body of rodent tendon and gut research (Vasireddi 2025).
• TB-500 has more evidence for tendon strength in the only rat study that tested both side by side (Biçer 2026) [Animal]. Its parent protein has controlled human trials in eye and heart disease, which do not apply directly to the fragment.
• Neither has a published randomized human trial for tendon, ligament or muscle injury. A 2026 review in Sports Medicine concluded that rigorous human safety data for unapproved peptides are scarce (Mendias 2026).

These are statements about the evidence, not a recommendation to use either peptide. Whether any treatment fits a specific injury is a decision for a licensed clinician.

Can BPC-157 and TB-500 be combined? (the “Wolverine stack”)

The pairing is marketed online as the “Wolverine stack”. Two studies bear on it:

• Rat tendon study (2026): 32 rats with a cut Achilles tendon were split into control, BPC-157, TB-500 and combined groups of eight. Both peptides were associated with better tissue findings; only TB-500 reached a significant strength gain; and combined treatment “did not confer additional benefits compared to either agent alone” [Animal, n=32] (Biçer 2026).
• Knee chart review (2021): of 16 patients, 4 received BPC-157 plus thymosin beta-4 and 3 of those 4 reported relief. The abstract does not say which form of thymosin beta-4 was used, and there was no control group [Human, case series, n=4 in this subgroup] (Lee 2021).

No controlled human study has tested the combination, and ClinicalTrials.gov lists no registered trial of it (registry search). Combining two unapproved products also combines their unknowns: FDA’s concerns about impurities and immune reactions apply to each (FDA).

Safety and regulatory status

What are the known risks?

• BPC-157: FDA says compounded BPC-157 “may pose risk for immunogenicity” (an immune reaction against the peptide) and may have problems with peptide-related impurities; it found “no, or only limited, safety-related information” (FDA). A 2025 systematic review found that no included study assessed safety or adverse events in humans (Vasireddi 2025).
• TB-500: FDA lists a risk of immunogenicity “due to the potential for aggregation” (clumping of peptide molecules), peptide-related impurities, and no identified human exposure data (FDA).
• Blood vessel growth and cancer (theoretical): in mice, melanoma cells engineered to overproduce Tβ4 formed more lung metastases, a mean of 46.7 vs 10.9 nodules [Animal] (Cha 2003). That study raised Tβ4 inside tumor cells rather than giving TB-500, so it raises a question, not a proven risk. BPC-157 is also pro-angiogenic in rats (Hsieh 2017). No long-term human study has tested cancer risk for either.

United States (FDA)

Neither peptide is an approved drug. FDA’s page on bulk substances that may present significant safety risks in compounding (Category 2), updated 2026-04-22, lists both under “nominated but withdrawn” (FDA). Withdrawal is not approval, and it is not Category 1. FDA’s Pharmacy Compounding Advisory Committee reviewed BPC-157 (for ulcerative colitis) and TB-500 (for wound healing) on July 23, 2026 (FDA). FDA adds substances to the 503A bulks list through notice-and-comment rulemaking, consulting that committee (FDA); as of 2026-09-29 no rule adding either peptide had been published.

Sport (WADA and USADA)

BPC-157 is prohibited under S0, non-approved substances (USADA). “Thymosin-β4 and its derivatives, e.g. TB-500” were added as named examples of prohibited growth factors under S2.3 in 2018 (USADA). A detection method for TB-500 has been published, with limits of 0.02 ng/mL in horse plasma and 0.01 ng/mL in urine (Ho 2012).

Other countries

This version covers US and anti-doping status only. Status in Australia, the UK and the EU was not re-verified against the regulators’ own pages for this edition and is not summarized here.

Doses used in studies

Peptide, route	Amount	Species	Study
BPC-157, intraperitoneal	10 µg/kg, 10 ng/kg or 10 pg/kg per day	Rat	Staresinic 2003
BPC-157, intraperitoneal	10 µg/kg per day	Rat	Biçer 2026
TB-500, intraperitoneal	60 µg/kg per day	Rat	Biçer 2026
BPC-157, IV	10 mg, then 20 mg	Human, n=2	Lee 2025
Tβ4 (not TB-500), IV	42–1,260 mg	Human, n=40	Ruff 2010

No established human dose exists outside approved labels.

How long do effects take in studies?

• BPC-157, rat tendon: healing measures were taken at days 1, 4, 7, 10 and 14 (Staresinic 2003) and up to day 21 in a tendon-detachment model (Krivic 2006) [Animal].
• TB-500 and BPC-157, rat tendon: outcomes were assessed after four weeks (Biçer 2026) [Animal].
• Tβ4, rat skin wounds: re-epithelialization (regrowth of the skin surface) was 42% higher than saline at day 4 and up to 61% higher at day 7 (Malinda 1999) [Animal].
• Tβ4, humans: dry-eye results at day 28 (Sosne 2015); heart-attack results at day 90 (Zhang 2025) [Human RCT].

Rat timelines do not translate into human recovery times, and no human timeline exists for TB-500.