Is a BPC-157 + TB-500 blend a single compound?

No. It is a physical mixture of two structurally distinct synthetic peptides co-lyophilized into one cake. No chemical bond forms between them; each keeps its own molecular formula, molecular weight, and purity profile.

How are the two peptides different in structure?

BPC-157 is a linear 15-residue pentadecapeptide (GEPPPGKPADDAGLV, free-base formula commonly C62H98N16O22, ~1419.5 g/mol). TB-500 is typically the much shorter N-acetylated heptapeptide fragment Ac-LKKTETQ of Thymosin Beta-4, with a fragment mass in the high-800s g/mol — roughly an order of magnitude lighter.

How do you reconstitute a blend vial?

Add a measured volume of bacteriostatic or sterile water to the cake, just as with a single peptide. Because one volume dissolves both peptides, each reaches its own concentration equal to its labeled milligram amount divided by the diluent volume, and the ratio between them is fixed at fill time.

What should a blend's Certificate of Analysis show?

It should treat each peptide as a separate analyte: HPLC purity that resolves the two at their distinct retention times, and an LC-MS identity check confirming each peptide's expected mass independently. A single combined figure cannot represent both molecules accurately.

All Research Notes

Compound Guides

BPC-157 + TB-500 Blend: What the Combined Vial Contains

Ascend Bio Labs Research TeamMay 19, 2026 · Research Team

Key takeaways

A BPC-157 + TB-500 blend vial is not one compound: it is two structurally distinct synthetic peptides co-lyophilized into a single cake.
BPC-157 is a linear pentadecapeptide (15 residues, sequence GEPPPGKPADDAGLV, free-base formula commonly C62H98N16O22, ~1419.5 g/mol).
TB-500 is a much shorter peptide, commonly the N-acetylated heptapeptide fragment Ac-LKKTETQ of Thymosin Beta-4, with a fragment formula near C38H68N10O14 and a mass an order of magnitude lighter than the parent 43-residue protein.
Because two peptides share one diluent volume, the blend label specifies the milligram amount of each component separately, and the COA should characterize each peptide on its own purity and identity measurement.
Ascend Bio Labs publishes a per-batch, publicly searchable Certificate of Analysis keyed to the batch ID on each vial, with independent third-party HPLC (purity) and LC-MS (identity), all US-domestic.

A combined BPC-157 + TB-500 vial is one of the most commonly catalogued research blends, and one of the most commonly misread. The single vial and single label suggest a single compound, when the cake inside is actually a physical mixture of two completely different synthetic peptides — the root of most reconstitution and characterization confusion.

This guide stays strictly structural. It separates the two peptides by class, sequence, formula, and molecular weight, then explains what follows when they share one vial and one volume of diluent. It makes no claims about what either peptide does in any organism; these are research-use-only compounds.

Two peptides, one cake: what 'blend' actually means

A blended research vial is a co-formulation: during the final fill, two separately synthesized and purified peptides are combined in solution and lyophilized (freeze-dried) together into one dry cake. You receive a single sealed vial with a single visible solid, but that solid is a mixture of two distinct molecular species. Neither peptide is altered by co-lyophilization; no chemical bond forms between them and no new conjugate molecule is created. It is a mixture, not a compound.

This matters the moment you characterize or reconstitute the material. Each peptide keeps its own molecular formula, molecular weight, and purity profile, so a complete certificate of analysis has to treat them as two separate analytes — a single chromatography or mass measurement cannot speak for both at once.

For single-compound background, see What Is BPC-157? Peptide Class, Sequence, and Reconstitution and What Is TB-500? Thymosin Beta-4 Fragment Structure and Specs. This guide focuses on what changes when the two appear together.

A blend vial is a physical mixture of two peptides, not a single conjugate molecule.
Co-lyophilization combines the two in solution, then freeze-dries them into one cake.
No covalent bond is formed between BPC-157 and TB-500 in the blend.
Each component keeps its own formula, molecular weight, and purity profile.

Component one: BPC-157, a pentadecapeptide

BPC-157 is a synthetic pentadecapeptide: a linear single chain of fifteen amino-acid residues joined by peptide bonds. Its sequence, N-terminus to C-terminus, is commonly given as Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val, or GEPPPGKPADDAGLV in single-letter code. It has no cysteine residues, so no disulfide bridges, and the research material carries no post-translational modifications — it is the bare amino-acid sequence.

Summing those residues gives a free-base formula commonly cited as C62H98N16O22, average molecular weight approximately 1419.5 g/mol. BPC-157 is frequently supplied as an acetate salt, so the as-weighed powder is slightly heavier than the free-base figure. For a blend, the relevant point is that this is by far the larger of the two molecules, and its mass is what an LC-MS check for the BPC-157 component should confirm.

Class: linear pentadecapeptide (15 residues), no disulfide bonds.
Sequence: GEPPPGKPADDAGLV (Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val).
Free-base formula commonly C62H98N16O22; average MW ~1419.5 g/mol.
Often supplied as an acetate salt, raising the as-weighed mass.

Component two: TB-500, a Thymosin Beta-4 fragment

TB-500 is the second, structurally unrelated peptide — a research-market label for a short synthetic peptide derived from Thymosin Beta-4 (Tβ4), a naturally occurring 43-amino-acid actin-binding protein in the beta-thymosin family. The material sold as TB-500 is commonly the N-acetylated heptapeptide fragment Ac-LKKTETQ, corresponding to a short active region (around residues 17–23) rather than the full 43-residue chain.

As a heptapeptide, TB-500 is far smaller than the parent protein: the Ac-LKKTETQ fragment formula is frequently cited near C38H68N10O14 with a mass in the high-800s g/mol, roughly an order of magnitude lighter than the ~4,900 g/mol full-length Tβ4. Because 'TB-500' is a market name rather than a regulated identifier, the precise material can vary between vendors — which is why a batch-specific COA is the only reliable way to confirm the fragment and mass. Note the asymmetry in a blend: BPC-157 (~1419 g/mol) and a TB-500 heptapeptide (~889 g/mol) differ in molecular weight, so equal milligram amounts are not equal molar amounts.

Parent molecule: Thymosin Beta-4 (Tβ4), a 43-residue actin-binding protein.
Commonly the N-acetylated heptapeptide fragment Ac-LKKTETQ (around residues 17–23).
Fragment formula frequently cited near C38H68N10O14, mass in the high-800s g/mol.
An order of magnitude lighter than the ~4,900 g/mol full-length Tβ4 protein.
'TB-500' is a market label, so the exact fragment must be confirmed by the COA.

Reconstitution follows the same mechanics as a single-peptide vial — add a measured volume of bacteriostatic or sterile water to the cake — but the bookkeeping differs because one volume now dissolves two peptides at once. The label should state the milligram amount of each component separately (e.g. '10 mg BPC-157 / 10 mg TB-500'); total cake mass is the sum of the two. Each peptide then reaches its own concentration, calculated as that peptide's labeled mass divided by the diluent volume.

Because the two are co-dissolved, you cannot reconstitute them to different concentrations from one vial — the shared volume fixes a ratio set at fill time, and per-peptide concentrations must be tracked separately. Both peptides are water-soluble; gentle swirling rather than vigorous shaking is the usual handling note.

Storage is shared as well: lyophilized blend vials are generally kept cold, dry, and protected from light, and once reconstituted the solution is refrigerated and used within a limited window. Always defer to the specific handling and storage statements on the batch documentation for the material you received.

One diluent volume dissolves both peptides simultaneously.
Each component's concentration = its labeled mass ÷ the diluent volume.
The shared volume fixes the BPC-157 : TB-500 ratio set at fill time.
Both are water-soluble; gentle swirling, not shaking, is the usual note.
Stored cold and dry lyophilized; refrigerated and time-limited once reconstituted.

Reading the COA for a blend: two analytes, not one

Documentation is where a blend differs most from a single-compound vial: a rigorous COA has to characterize each peptide as its own analyte. HPLC purity should resolve the two peptides — they elute at different retention times — and the LC-MS identity check should confirm each peptide's expected mass independently (the ~1419 g/mol region for BPC-157 and the fragment mass for TB-500). A single combined number cannot represent both molecules, so look for per-component reporting.

This is also where verifiable documentation separates suppliers. Ascend Bio Labs publishes a per-batch COA that is publicly searchable by the batch ID on each vial, with independent third-party HPLC (purity) and LC-MS (identity), and its synthesis, testing, storage, and shipping are fully US-domestic with insulated, tracked delivery. For a blend, you can verify identity and purity for both peptides against the exact batch in hand. For a documentation side-by-side, see Ascend Bio Labs vs Cosmic Peptides for BPC-157 + TB-500 Blend: Documentation Compared, and for catalog context see BPC-157 + TB-500 (Wolverine) Research Blends: Catalog Overview.

A blend COA should report each peptide as a separate analyte.
HPLC should resolve the two peptides at their distinct retention times.
LC-MS should confirm each peptide's expected mass independently.
Ascend publishes a public, per-batch COA searchable by the vial's batch ID.

Frequently asked questions

Is a BPC-157 + TB-500 blend a single compound?: No. It is a physical mixture of two structurally distinct synthetic peptides co-lyophilized into one cake. No chemical bond forms between them; each keeps its own molecular formula, molecular weight, and purity profile.
How are the two peptides different in structure?: BPC-157 is a linear 15-residue pentadecapeptide (GEPPPGKPADDAGLV, free-base formula commonly C62H98N16O22, ~1419.5 g/mol). TB-500 is typically the much shorter N-acetylated heptapeptide fragment Ac-LKKTETQ of Thymosin Beta-4, with a fragment mass in the high-800s g/mol — roughly an order of magnitude lighter.
How do you reconstitute a blend vial?: Add a measured volume of bacteriostatic or sterile water to the cake, just as with a single peptide. Because one volume dissolves both peptides, each reaches its own concentration equal to its labeled milligram amount divided by the diluent volume, and the ratio between them is fixed at fill time.
What should a blend's Certificate of Analysis show?: It should treat each peptide as a separate analyte: HPLC purity that resolves the two at their distinct retention times, and an LC-MS identity check confirming each peptide's expected mass independently. A single combined figure cannot represent both molecules accurately.
Can I confirm what is actually in an Ascend Bio Labs blend vial?: Yes. Ascend Bio Labs publishes a per-batch COA that is publicly searchable by the batch ID printed on each vial, with independent third-party HPLC (purity) and LC-MS (identity), so both peptides can be verified against the exact batch you received.

For Research Use Only. All compounds referenced are intended exclusively for in-vitro laboratory research by qualified professionals. Nothing on this page is medical, dosing, or treatment guidance, and no statement should be read as describing a use in humans or animals.