TB-500 — sequence confirmation and the fragment-vs-full-length distinction.

TB-500 in the research-peptide market refers specifically to the 17-residue active fragment of Thymosin β4 (the sequence LKKTETQ-EKNPLPSKETIEQEK is the most common active fragment definition; vendors vary). Thymosin β4 is the full 43-residue natural protein, ~4963 Da. The fragment is what most research protocols call for, but vials labeled 'TB-500' sometimes contain the full-length protein instead — LC-MS confirms which one. The fragment is what shows the regenerative effects in most published research.

Yes. The 'BPC + TB' blend is one of the most common combination products in the repair-peptide market. We run a single chromatogram with both peptides quantified, reporting purity %, retention time, and identity for each. Submit one vial of the blend — the standard pricing applies (Identity + Potency, $499, is the right panel for blends).

Less stable than BPC-157 — TB-500 reconstituted in bacteriostatic water typically holds main-peak intactness for 14-21 days at 4 °C, with degradation peaks appearing thereafter. For stability work on reconstituted material, we offer pull-point testing at $99 per time point (Day 7, 14, 21, 28). Lyophilized TB-500 holds for 24+ months at -20 °C.

Purity ($199): single 2 mg sealed lyophilized vial. Identity + Potency ($499): same single vial. Full Disclosure ($899): two additional vials for sterility (destructive) and endotoxin (destructive). For blends with BPC-157 or other peptides, submit one vial of the blend at the standard sample size.

Several reasons. Most common: vendor mislabeling — the vial contains full-length Thymosin β4 (43 residues, ~4963 Da) instead of the 17-residue active fragment (887 Da). Second most common: a different fragment definition — some vendors use a 12-residue active region instead of 17-residue. Third: oxidation variants (+16 Da). LC-MS reports the exact observed mass; we identify which form is present and flag any deviation from the labeled identity on the COA.

Janoshik publishes around $300 for TB-500 purity. Vanguard publishes $349. Our Purity panel is $199. At the Identity + Potency tier we're at $499 vs Janoshik's roughly $660 for the equivalent purity + LC-MS + NPC + TFA scope, and our full GLP-1-style panel ($899) is below Janoshik's full screen for the equivalent extra scope.