What the label states, the lot delivers — net peptide mass, not gross powder weight, purity reported as measured rather than rounded up, and a Certificate of Analysis for every lot.
Net peptide mass, not powder weight; purity as measured, not rounded up; a COA per lot.
Net peptide + purity not rounded up. COA per lot.
FDA PCAC reviews 7 peptides for the 503A bulks list (BPC-157, KPV, TB-500, MOTs-C, Emideltide, Semax, Epitalon). Read our compounder's decision tree. Read our briefing →
FDA PCAC reviews 7 peptides for the 503A bulks list in July. Read →
FDA PCAC: 7 peptides under review. Read →
Thymosin β4 fragment
Vialdyne primary owner
This Vialdyne page is the primary SEO owner for buyers evaluating TB-500 through a pharmacy QA, clinic procurement, or regulated-sourcing workflow. It should answer whether the buyer can request a batch COA, release-test scope, destination-market review, and add-on documentation before moving into pricing or repeat inventory planning.
Overview
TB-500 is a 43-residue synthetic peptide derived from Thymosin beta-4, the actin-sequestering protein expressed across essentially every mammalian cell type. Biological activity centres on actin binding via the central LKKTETQ motif, with downstream effects on cell migration, angiogenesis, and tissue regeneration, the mechanistic substrate for the published TB-500 literature on wound healing, cardiac remodelling, and tendon-ligament repair models. The 43-residue length keeps the molecule serum-stable but gastric-labile, so all documented use is via injectable routes. For 503A patient-specific compounders, TB-500 is scheduled for FDA PCAC review at the July 2026 meeting against the 503A bulks-list criteria, with the proposed indication of wound healing. Vialdyne releases TB-500 acetate as a lyophilised powder against a ≥99.0% main-peak HPLC specification. At 43 residues the sequence sits in the upper-middle of routine SPPS, synthesis is reliable but the purification regime has to work harder than for shorter peptides like BPC-157, and the standard release packet leans on peak-integration HPLC plus ESI-MS to clear closely-eluting deletion sequences. LC-MS/MS sequence verification is the recommended add-on test at any first-time pharmacy qualification: for a 43-mer, the residue-mass ambiguity of mass-spec alone is meaningfully larger than for a 15-mer, and only tandem MS demonstrates that the synthesised sequence matches the labelled one. TB-500 is dispensed either as the standalone vial or co-lyophilised with BPC-157 as the Wolverine Blend (5+5 mg per 10 mg vial standard; non-standard ratios available under change-control). Two companion pieces flesh out the procurement picture: our mechanism-and-analytics [BPC-157-vs-TB-500 comparison](/insights/bpc-157-vs-tb-500-side-by-side), and the regulatory-framing [overview of 503A vs 503B compounding pathways](/insights/503a-vs-503b-compounding-pharmacy-peptides).
Applications & buyer fit
Repair peptides, BPC-157, TB-500, and related sequences, typically ship to research labs studying tissue-repair, gastrointestinal, or tendon-ligament models, and to compounding pharmacies that have validated the active material into their workflow. The synthesis itself is reliable, but analytical confirmation is where suppliers differ, buyers qualifying a new source should request sequence verification by tandem MS on the first batch and compare against the labelled sequence directly.
Sourced for
Buyer fit
Documentation that ships
Procurement note: Buyers qualifying a new source typically request tandem-MS sequence verification on the first lot, compared against the labelled sequence.
Primary buyer fit: 503A / 503B compounding pharmacies and academic and contract research laboratories.
Specifications
Certificate of Analysis
Published released-batch COAs for TB-500, every lot HPLC-verified. These are previews — request the full high-resolution certificate for any lot.
VerifiedRequest full COA →TB-500
VD260428-TB10195 · 98.88%
VerifiedRequest full COA →TB-500
VD260428-TB193 · 99.30%
VerifiedRequest full COA →TB-500
VD260428-TB5194 · 99.53%
Regulatory note
The FDA's PCAC is presently reviewing TB-500 (July 2026) for the 503A bulks list, the proposed indication being wound healing.
Selected literature
Frequently asked questions
TB-500 is a 43-residue synthetic peptide corresponding to the mature, N-terminally acetylated form of native Thymosin beta-4 (43 residues in its mature acetylated chain; the 44-residue figure refers to the precursor including the initiator methionine). The synthetic sequence preserves the LKKTETQ actin-binding motif that drives biological activity. Two practical advantages distinguish synthetic TB-500 from recombinant full-length Thymosin beta-4: it is materially cheaper to produce at compounding-pharmacy scale, and it sidesteps the lot-to-lot variability inherent in cell-line-expressed biological products. For the actin-binding and tissue-regeneration endpoints that dominate the published literature, per-mass activity is functionally equivalent between the two.
Length is the issue. At 43 residues, TB-500 sits at the upper-middle of routine SPPS, and longer peptides accumulate single-residue deletion sequences during synthesis that elute right up against the target peak on RP-HPLC. They pass the standard purity-percentage gate but are not the molecule on the label. Mass spec resolves identity to within 0.5 Da of theoretical, but cannot distinguish a Lys-deletion at position 12 from a Lys-deletion at position 30, both have the same residue mass. Only LC-MS/MS with a full b- and y-ion ladder demonstrates positional integrity. This is the standard qualification test we recommend for any 40-plus residue peptide entering a new pharmacy's quality system.
Mechanistically the two peptides are not interchangeable. TB-500 works through actin sequestration, modulating cell migration and tissue remodelling. BPC-157 works through nitric-oxide-pathway modulation and growth-factor-receptor cross-talk. The complementary mechanisms are why the two get combined so frequently in repair-focused compounding protocols. The Wolverine Blend SKU presents both peptides in a single co-lyophilised vial at a 5+5 mg standard ratio (other ratios under change-control), with a single COA certifying both component purities and the in-vial ratio, which reduces the document-handling burden on the receiving pharmacy's QA file.
