Notice: Neither BPC-157 nor TB-500 is approved as a medicinal product for human use in any country. This text is for information only and is based on published studies and assessments by regulatory authorities. Arion Bios products are intended exclusively for laboratory and research purposes. They are not medicines or dietary supplements and are not intended for use in humans or animals.

BPC-157 and TB-500 appear together so often, in product listings and in discussions alike, that many people assume they are similar substances. Both are studied in connection with tissue healing, both are on the WADA Prohibited List, and both are among the six peptides that the US Department of Health and Human Services opened the way to pharmacies for on 28 October 2026. That is where the similarity ends.

Each comes from a different protein, has a different structure and is studied for different biological processes. The evidence behind them also differs a great deal. Below you will find a comparison of their origin, structure, mechanism, animal and human studies, and regulation. At the end, we explain how a certificate of analysis shows which of the two a sample contains.

The key differences at a glance

  • Origin: BPC-157 is a section of a protein from human gastric juice. TB-500 is a section of thymosin beta-4, a protein found in almost every cell.
  • Size: BPC-157 has 15 amino acids (1419.5 g/mol), TB-500 only seven (889.0 g/mol).
  • Mechanism: research on BPC-157 focuses mainly on blood vessel formation and the nitric oxide system, but its molecular target is unknown. Thymosin beta-4 binds actin and enables cells to move.
  • Human evidence: BPC-157 has five small clinical studies. No study of TB-500 itself has been published; the phase 1 to 3 trials involved the whole thymosin beta-4 protein.
  • Regulation: neither is approved as a medicine anywhere in the world, and both are banned in sport.

Where they come from

BPC-157 was first described in 1993 by Predrag Sikirić’s group at the School of Medicine of the University of Zagreb. It is a synthetic peptide of 15 amino acids with the sequence GEPPPGKPADDAGLV. It is a section of a protein that the authors isolated from human gastric juice and named BPC (body protection compound). The Croatian pharmaceutical company Pliva later developed it under the code PL 14736 as a possible treatment for ulcerative colitis.

TB-500 is based on thymosin beta-4 (Tβ4), a protein of 43 amino acids present in almost every cell of the human body. In its July 2026 evaluation, the US Food and Drug Administration (FDA) describes TB-500 as a synthetic section of thymosin beta-4 covering positions 17 to 23, with an acetyl group at the start of the chain: Ac-LKKTETQ. In the whole protein, this is the region that binds actin.

The name TB-500 is not an official chemical or drug name, though. The FDA notes that various salts and derivatives are sold under it, and in practice the name is sometimes used for the whole thymosin beta-4 protein as well. We cover this in detail in TB-500 and Thymosin Beta-4: How It Works and What Studies Show.

Comparison table

Parameter BPC-157 TB-500
Parent protein BPC from human gastric juice Thymosin beta-4 (43 amino acids)
Sequence GEPPPGKPADDAGLV Ac-LKKTETQ (positions 17–23 of Tβ4)
Length 15 amino acids 7 amino acids
Molecular formula C62H98N16O22 C38H68N10O14
Molecular weight 1419.5 g/mol 889.0 g/mol
Main processes studied Blood vessel formation, nitric oxide system, tendon cells Actin binding, cell movement, blood vessel formation
Known molecular target Not identified Actin (shown for the whole Tβ4 protein)
Animal studies Hundreds of papers across tissues Mostly with the whole Tβ4 protein
Human studies Five small studies None; the whole Tβ4 protein went through phase 1–3 trials
Approved as a medicine Nowhere in the world Nowhere in the world
WADA Prohibited, category S0 Prohibited, category S2

The formulas and molecular weights come from the FDA’s 2026 evaluations. For TB-500 they refer to the free base, i.e. the peptide without a salt.

Mechanism: two different routes

BPC-157

Three themes recur in cell and animal studies of BPC-157. The peptide influenced the nitric oxide system, which among other things regulates blood flow. It promoted the formation of new blood vessels, an effect a 2017 study linked to activation of VEGFR2, the receptor through which vascular endothelial growth factor (VEGF) acts. And in cultured cells from rat Achilles tendon it increased cell survival and migration (2011) and the number of growth hormone receptors (2014).

A complete picture is missing, however. In its July 2026 evaluation, the FDA states that the molecular target of BPC-157 has not been identified and that its mechanism of action remains poorly understood. In animals, the peptide also disappears from the blood within minutes: its half-life ranged from 5.3 minutes in dogs to 15.2 minutes in rats.

TB-500 and thymosin beta-4

Thymosin beta-4 is the main actin-binding protein in cells. It holds a reserve of free actin molecules from which the cell builds the filaments of its skeleton when it needs to move. Studies of the whole protein added the promotion of blood vessel formation, protection of heart cells via the enzyme ILK, and reduced scarring.

Two papers from 2003 are key for TB-500. The LKKTETQ section promoted blood vessel formation and, applied to the skin of aged mice, sped up wound healing in a similar way to the whole protein. However, this was the section without the acetyl group. The FDA points out that acetylation changes a peptide’s charge and size, so these results cannot automatically be applied to TB-500. In a 2024 laboratory study, TB-500 itself did not speed up the closure of an artificial “wound” in a layer of cells. Only one of its breakdown products, the shorter peptide Ac-LKKTE, had a small effect.

What the studies have shown

BPC-157: extensive animal data

There are hundreds of preclinical papers on BPC-157. In rats with a transected Achilles tendon it sped up healing (2003), and other studies described effects on muscle, bone, ligaments and above all the digestive tract. A 2025 systematic review looked at the literature from the perspective of orthopaedics and sports medicine: of the 36 studies included, 35 were preclinical and only one was clinical. The authors conclude that they found no clinical safety data in humans.

BPC-157 in humans

In its 2026 evaluation, the FDA identified five clinical studies in the scientific literature:

  • safety studies in healthy volunteers who received BPC-157 rectally (Veljaca et al., 2002 and 2003),
  • a phase 2 study in people with ulcerative colitis (Ruenzi et al., 2005), published only as a conference abstract,
  • a retrospective review of 17 patients with knee pain who received the peptide by injection into the joint (Lee and Padgett, 2021),
  • a pilot study in 12 patients with interstitial cystitis, an inflammation of the bladder (Lee et al., 2024),
  • a pilot safety study of intravenous administration in two healthy volunteers (Lee and Burgess, 2025).

The studies reported no serious adverse events. The FDA stresses, however, that they were short and small and that their safety data are patchy. According to the FDA, even the ulcerative colitis study does not demonstrate efficacy, because the results cannot be reliably assessed from a conference abstract. The FDA found no studies in which people received BPC-157 under the skin, by mouth or through the nose.

TB-500 and thymosin beta-4 in humans

This is where a distinction is needed. The whole thymosin beta-4 protein has been through clinical trials run by the US company RegeneRx: by injection in healthy volunteers (phase 1, 2010), as a gel for venous leg ulcers (phase 2, 73 patients, 2010) and as eye drops for dry eye (phase 2, 72 participants, 2015). It was well tolerated, but has not yet shown a convincing effect and is not approved.

No human study of TB-500 itself, the seven-amino-acid section, has been published. In its July 2026 evaluation, the FDA states that it found not a single case in the scientific literature of TB-500 being given to patients. Nor did it find animal studies examining its effect on wound healing. When TB-500 is described as a “peptide with clinical trials”, the data actually concern the whole protein.

The result is an interesting paradox. There is more human data on the BPC-157 molecule itself than on TB-500. Yet the most developed clinical programme belongs to thymosin beta-4, the protein TB-500 comes from.

Why they are mentioned together, and what we know about combining them

Both peptides are studied in connection with tissue healing, but each by a different route: BPC-157 mainly via blood vessels and nitric oxide, thymosin beta-4 via cell movement. Hence the idea that they might complement each other, and the blends of both substances sold under various names.

We found no published controlled study of the combination. The only mention in humans comes from the 2021 retrospective knee pain review mentioned above: four of the patients received BPC-157 together with thymosin beta-4. The study had no control group and pain was assessed by telephone, so no conclusions can be drawn from it.

For research, a blend has a further drawback: the certificate of analysis has to confirm the identity and amount of each component separately. And the US rules of October 2026 do not cover blends, because they require a product with a single active ingredient.

Regulation in the EU, the US and sport

Neither BPC-157 nor TB-500 is authorised as a medicine in the EU or anywhere else. In its 2026 evaluation, the FDA states that no approved product containing BPC-157 exists in any country. Both are available only as research substances labelled “research use only”.

In the US, the situation has changed considerably over three years:

  • 2023: the FDA placed BPC-157 and the thymosin beta-4 fragment among substances with safety risks that pharmacies were not allowed to use for compounding.
  • 23 July 2026: the FDA’s Pharmacy Compounding Advisory Committee (PCAC) voted 8 to 6, with one abstention, for each substance to be placed on the list of substances pharmacies may use. FDA scientists had recommended the opposite: in their view, evidence of safety and effectiveness is lacking and neither substance is adequately characterised chemically.
  • 28 October 2026: the Department of Health and Human Services (HHS) announced that it will not take action against pharmacies that compound BPC-157, TB-500 and four other peptides on prescription under set conditions. The bulk substance must come from an FDA-registered facility and have a certificate of analysis, the manufacturer must follow good manufacturing practice (GMP), and the product may contain only one active ingredient. This is not drug approval. Comments can be submitted until 13 November 2026.

We cover the HHS decision in more detail in Peptide News 44/2026. Nothing changes for Europe.

In sport, both substances are prohibited at all times, in and out of competition. The WADA list names BPC-157 explicitly in category S0, non-approved substances. Thymosin beta-4 and its derivatives, including TB-500, belong to category S2, growth factors and growth factor modulators. In 2016, 34 players of the Australian football club Essendon received two-year bans over thymosin beta-4.

Quality: how to tell what is in a sample

For both substances, the name on the label is not enough. The FDA criticised inconsistent naming and missing impurity data for both BPC-157 and TB-500. What matters is the certificate of analysis (CoA) and two different results in it:

  • HPLC (high-performance liquid chromatography) shows purity, i.e. what proportion of the sample is the main component. It says nothing about which molecule it is.
  • MS (mass spectrometry) measures the mass of the molecule and compares it with the theoretical value. For BPC-157 this is approximately 1419 Da, for TB-500 in the Ac-LKKTETQ form approximately 889 Da, and for the whole thymosin beta-4 protein around 4,960 Da.

Mass spectrometry therefore reliably distinguishes BPC-157 from TB-500, and the short fragment from the whole protein. We explain how to read a certificate in Peptide Certificate of Analysis: How to Read a CoA. How to handle lyophilised peptides so that they keep their quality is covered in How to Store Peptides: Powder, Solution and the Cold Chain.

What Arion Peptides offers

Our range includes BPC-157 10 mg as a lyophilised powder in a vial. TB-500 is not in stock yet. Certificates of analysis for Arion Bios batches are available on the certificates of analysis page. The products are intended exclusively for laboratory and research purposes.

Detailed reviews of the studies on each substance can be found in BPC-157: Vast Animal Data, Thin Human Evidence and TB-500 and Thymosin Beta-4: How It Works and What Studies Show.

Frequently Asked Questions

Is BPC-157 the same as TB-500?

No. BPC-157 is a 15-amino-acid section of a protein from gastric juice, TB-500 a seven-amino-acid section of thymosin beta-4. They differ in origin, structure and the mechanism studied.

Which one has more human evidence?

For the molecule itself, BPC-157 has more studies: five small, short ones, none of them a larger controlled trial. No human study of TB-500 has been published. The phase 1 to 3 trials involved the whole thymosin beta-4 protein, not the TB-500 fragment.

Has the combination of BPC-157 and TB-500 been studied?

We found no controlled study of the combination in the literature. The only mention is four patients in a 2021 retrospective knee pain review without a control group.

What does the US decision of October 2026 mean for them?

The US Department of Health and Human Services will not take action against pharmacies that compound them on prescription under strict quality conditions. This is not drug approval, and the final decision on the list of substances for pharmacies is still to come. Nothing changes in the EU.

Are BPC-157 and TB-500 banned in sport?

Yes, both are prohibited on the WADA list at all times: BPC-157 in category S0, TB-500 as a thymosin beta-4 derivative in category S2.

How can I tell which substance a sample contains?

From the mass spectrometry result in the certificate of analysis. A mass of approximately 1419 Da corresponds to BPC-157, approximately 889 Da to TB-500 and around 4,960 Da to the whole thymosin beta-4 protein. HPLC purity alone does not confirm identity.

Summary

What BPC-157 and TB-500 mainly have in common is that both are studied in connection with tissue healing. Otherwise they are different molecules: BPC-157 is a 15-amino-acid section of a gastric juice protein with extensive animal data and five small human studies. TB-500 is a seven-amino-acid section of thymosin beta-4, and most of the results attributed to it actually concern the whole protein.

Neither substance is approved as a medicine, and both are banned in sport. The US decision of October 2026 opened access to both through pharmacies under strict conditions, but it does not change their status in Europe. For research, knowing exactly what is in the sample is key. The answer comes from a certificate of analysis with mass spectrometry.

Sources

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  2. Staresinic M, Sebecic B, Patrlj L et al., “Gastric pentadecapeptide BPC 157 accelerates healing of transected rat Achilles tendon and in vitro stimulates tendocytes growth”, Journal of Orthopaedic Research, 2003;21(6):976–983. DOI: 10.1016/S0736-0266(03)00110-4
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