BPC-157 vs TB-500: Two Research Peptides Compared
BPC-157 and TB-500 are often mentioned together and are sold together in blends, but they are unrelated molecules. This post compares where each comes from, how big each is, which mechanisms the literature studies, and how each is identified in the laboratory.
Research blog: general laboratory-science and literature context. Not medical advice. Sealed Peptides materials are for laboratory research use only, and are not for human or veterinary use.
Two different origins
BPC-157 is a synthetic 15-residue peptide (GEPPPGKPADDAGLV). It was described as a partial sequence of a larger "body protection compound" reported from gastric juice, and it has no exact counterpart among well-characterized human proteins.
TB-500 is a synthetic peptide modeled on a short region of Thymosin Beta-4, a 43-residue actin-binding protein found in most cells. Material sold as TB-500 is usually described as the acetylated LKKTETQ segment that corresponds to the actin-binding motif of the full protein.
Size and chemistry at a glance
- BPC-157: 15 residues, listed molecular weight about 1419.5 Da, no modifications at either end in the usual description.
- TB-500: a short acetylated fragment, listed molecular weight about 889 Da, rich in lysine and threonine.
- Shared traits: both are supplied as lyophilized powders and both are small enough to be checked by electrospray mass spectrometry in a single charge-state window.
What the literature studies
BPC-157 papers come largely from one research group and use rodent models of tissue injury, with endpoints such as vessel growth markers and nitric oxide signaling. Reviewers note the limited independent replication.
Thymosin Beta-4 research centers on actin sequestration: the protein binds monomeric G-actin and regulates filament assembly, which ties it to cell-migration studies. Much of that literature concerns the full protein rather than the short TB-500 fragment, which is an important distinction when reading it.
Why they appear together
Because both compounds show up in tissue-model literature, vendors often list them side by side or in a combined vial. A blend is simply two materials in one vial; no published study of the blend itself is cited on this site. See the BPC-157 / TB-500 blend page for its listed contents.
Characterizing each in the lab
Identity is usually confirmed by mass spectrometry against the expected mass, and purity is reported as HPLC area percent. Our guides on HPLC purity and mass spectrometry explain what each measurement does and does not show.
Terms used in this guide
Related tools and guides
For laboratory research use only. Not for human or veterinary use. This post is general chemistry and literature context and does not describe or endorse any use of Sealed Peptides products.