BPC-157 vs TB-500: Two Different Peptides Often Sold Together

BPC-157 and TB-500 are unrelated peptides that are frequently sold together, either side by side or in a single blended vial. BPC-157 is a 15-residue peptide, GEPPPGKPADDAGLV, with a molecular weight of about 1419.5 Da. TB-500 is a seven-residue acetylated peptide, Ac-LKKTETQ, corresponding to residues 17 to 23 of thymosin beta-4, with a molecular weight of about 889.0 Da. They share no sequence, origin or mechanism described in the literature.

Where does each peptide come from?

BPC stands for Body Protection Compound. BPC-157 is described as a partial sequence of a protein found in gastric juice, and nearly all of its published literature comes from one research group in Zagreb, which has reviewed its work in rodent models of wound and tissue injury [1]. TB-500 is a fragment of thymosin beta-4, a 43-residue actin-binding peptide [3]. Supplier catalogs use the name TB-500 for the acetylated 17-23 fragment, which contains the actin-binding motif LKKTET [4].

How much literature covers each one?

BPC-157 has hundreds of papers, overwhelmingly in rats and in cell culture, including work on tendon fibroblasts in vitro [2]. TB-500 as a seven-residue fragment has a much thinner literature of its own; most papers that are cited for it actually studied full-length thymosin beta-4. That difference matters when reading claims about the fragment.

The concentration of BPC-157's literature in one research group is itself a reading instruction: independent replication outside that group is limited, which is why careful summaries describe the compound's evidence as extensive but narrow. For TB-500 the instruction is different - check whether a cited study used the full 43-residue protein or the seven-residue fragment, because results from one do not automatically describe the other.

What is their regulatory status?

Neither peptide is an approved drug anywhere. BPC-157 appears on the FDA's list of substances that may not be compounded (Category 2, substances with significant safety risks in compounding), and both are prohibited in sport under the World Anti-Doping Agency's rules, which is why anti-doping bodies publish warnings about them. For research suppliers this status defines the only lawful framing: materials for laboratory research, with no human-use claims. A vendor page that pairs these molecules with human performance language is advertising its own non-compliance.

How are they distinguished in the laboratory?

By mass and by retention time. Their average molecular weights differ by about 530 Da, and their HPLC retention differs because of their different composition. In a blended vial both appear as separate peaks, and a complete report gives a purity value and an identity result for each component, not a single combined number.

The masses are the quick check on any certificate: about 1419.5 Da for BPC-157 and about 889.0 Da for the TB-500 fragment. A certificate for either compound reporting a mass far from its reference value - or a blend certificate showing only one mass - describes a different product than the label does.

Why are they combined?

The pairing became common in supplier catalogs and online communities, where the blend is sometimes called by informal names - "Wolverine stack" is the one most often attached to this pair. The combination reflects market convention rather than a body of research on the two peptides used together: the published literature contains no controlled studies of the pair as a combination, so the blend's popularity is a fact about the market, not about the evidence.

What should a buyer check on a blended vial?

Four things. That the label states each component's mass separately rather than only a total; that the certificate reports purity and identity per component, as two peaks and two observed masses; that each component's mass matches its reference value; and that the lot number ties the vial to a record carrying all of the above. A blend certificate with a single purity figure and no per-component masses is incomplete by construction.

Frequently asked questions

Is TB-500 the same as thymosin beta-4?

No. TB-500 is a seven-residue fragment; thymosin beta-4 has 43 residues and a molecular weight of about 4963 Da.

Can one CAS number cover both?

No. Each peptide has its own CAS number: 137525-51-0 for BPC-157 and 885340-08-9 for the TB-500 fragment. A blend lists both.

What is the Wolverine stack?

An informal name used in online communities for the combination of BPC-157 and TB-500. The name comes from marketing and forum culture; the published literature contains no controlled studies of the two peptides as a combination.

Is either peptide FDA-approved?

No. Neither is an approved drug; BPC-157 is additionally listed in Category 2 of the FDA's compounding nomination lists, and both are prohibited in sport under WADA rules.

How does FLASK list them?

FLASK lists BPC-157 (5 mg and 10 mg), TB-500 (10 mg), and a BPC-157 / TB-500 5 + 5 mg blend, each with component data on the product page.