Quick answer
A BPC-157 + TB-500 blend is reconstituted like any lyophilized peptide: add a measured volume of bacteriostatic water slowly down the vial wall and swirl gently until clear. The one difference is the math, because a blend has three concentrations: one for each component and one for the total. For a 10 mg / 10 mg blend vial, 2 mL of diluent gives 5 mg/mL of BPC-157 and 5 mg/mL of TB-500 (10 mg/mL total peptide). Store the solution at 2–8 °C, protected from light, and use it within 28 days. Do not vortex: TB-500 is the larger, more fragile component.
- Multi-use stock: bacteriostatic water (0.9% benzyl alcohol)
- Cell culture: sterile PBS or unpreserved sterile water, prepared fresh
- Per-component formula: component mg ÷ mL added = component mg/mL
- Calculator: V8 reconstitution calculator
BPC-157 and TB-500 are frequently studied together in preclinical cell-migration and angiogenesis models, and a co-lyophilized blend vial is a convenient way to keep the ratio fixed across an experiment. Blends do raise questions that single-peptide vials do not: which component limits solubility, how to express concentration, and whose stability sets the clock. This guide answers those questions with worked tables for blend vials and for separate vials combined at the bench. For laboratory research use only; not for human consumption.
Why reconstitution protocol matters for a two-peptide blend
The two components are very different molecules, and the blend has to be handled to suit the more demanding of the two.
| Property | BPC-157 | TB-500 (thymosin β4) |
|---|---|---|
| Length | 15 amino acids | 43 amino acids, N-terminally acetylated |
| Approximate molecular weight | 1,419.5 g/mol | 4,963 g/mol |
| 1 mg/mL in molar terms | ≈ 704 µM | ≈ 201 µM |
| Aqueous solubility | High | High; acidic, strongly hydrophilic |
| Oxidation-sensitive residues | None (no Met, Cys or Trp) | Methionine at position 6 |
| Agitation sensitivity | Low | Moderate; longer chain, foams |
| Limiting factor in a blend | — | Usually TB-500 |
Two practical points follow. First, equal milligrams are not equal moles: in a 10 mg / 10 mg blend there are roughly 3.5 molecules of BPC-157 for every molecule of TB-500. Second, TB-500's methionine can oxidize to the sulfoxide in solution, so headspace air, light and time matter more for the blend than for BPC-157 alone. Comparative background is in BPC-157 vs TB-500 and BPC-157 and TB-500 combination research.
Materials you will need
- Lyophilized blend vial (for example, the BPC-157 + TB-500 10 mg / 10 mg blend), or separate vials of BPC-157 and TB-500
- The batch certificate of analysis, to confirm the stated mass of each component
- Bacteriostatic water, in date and within 28 days of first puncture
- Sterile 1 mL and 3 mL syringes with sterile needles, or calibrated pipettes with sterile tips
- 70% isopropyl alcohol swabs and nitrile gloves
- Low-protein-binding polypropylene tubes if aliquoting
- Labels, marker, sharps container, and a clean bench or laminar-flow hood
Diluent selection: BPC-157 vs TB-500
BPC-157 diluent options
BPC-157 is a short, hydrophilic peptide that dissolves almost instantly in water. Bacteriostatic water is the standard choice for a stock that will be entered repeatedly. Unpreserved sterile water suits single-session analytical work, and sterile PBS is appropriate where an assay needs physiological pH and ionic strength.
TB-500 diluent options
TB-500 is also freely water-soluble, and bacteriostatic water is again the default for multi-use stock. Because it is a larger molecule with an oxidizable methionine, it benefits from prompt refrigeration and minimal headspace. For cell-based work, use PBS or culture medium without benzyl alcohol.
Diluent choice for the blend
| Diluent | Suitable for the blend? | Best use | Limitation |
|---|---|---|---|
| Bacteriostatic water (0.9% benzyl alcohol) | Yes — default | Multi-use stock held at 2–8 °C | Not for cell culture; benzyl alcohol is cytotoxic |
| Sterile water, unpreserved | Yes | Same-day analytical preparation | Single use; no preservative |
| Sterile PBS, pH 7.4 | Yes | Cell-based assays | Single use; prepare fresh |
| Dilute acetic acid | Not needed | — | Both peptides dissolve without it |
| Tap, distilled or deionized water | No | — | Not sterile; endotoxin uncontrolled |
More on the default diluent: bacteriostatic water for peptides.
Step-by-step reconstitution protocol
Step 1: Preparation
Remove the blend vial and the diluent from cold storage and let them stand unopened for 15–20 minutes. Wipe down the work surface with 70% isopropyl alcohol, put on gloves, and check the vial: the cake should be white to off-white and dry. Confirm the lot number against the COA and note the stated mass of each component.
Step 2: Choose and measure the diluent volume
Select a volume from the concentration tables below and write the resulting per-component concentration on the label before you begin. Swab both stoppers and allow them to dry. Draw the diluent into a sterile syringe and clear any bubbles.
Step 3: Add the diluent to the peptide vial
Pass the needle through the stopper at an angle and rest the tip against the inside of the glass. Release the liquid slowly so it runs down the wall and wets the cake from below. If the vial is under vacuum, hold the plunger back so the liquid is not pulled in as a jet.
Step 4: Dissolve without vortexing
Swirl the vial in slow circles or roll it between the fingers. BPC-157 goes into solution within seconds; TB-500 follows within one to three minutes. Do not shake or vortex. If any solid remains, stand the vial upright for five to ten minutes and swirl again.
Step 5: Inspect the solution
View the vial against white and dark backgrounds. The solution should be clear, colorless and free of particles. A few surface bubbles are normal and will clear. Persistent haze or visible particles mean the vial should not be used.
Step 6: Aliquot if needed
If the stock will not be finished within four weeks, or if the experiment calls for frozen storage, divide it into single-use aliquots in low-bind tubes immediately. Each aliquot should be thawed once and never refrozen.
Step 7: Label and refrigerate
Record both component concentrations (for example, "BPC-157 5 mg/mL + TB-500 5 mg/mL"), the diluent, lot number, date and initials. Store upright at 2–8 °C, away from light.
Concentration calculation reference
For a blend, apply the standard formula to each component separately:
- Component concentration (mg/mL) = component mass (mg) ÷ diluent volume (mL)
- Total peptide concentration (mg/mL) = sum of component masses (mg) ÷ diluent volume (mL)
- Diluent volume (mL) = component mass (mg) ÷ target component concentration (mg/mL)
The ratio between the two peptides is fixed at manufacture and cannot be changed by dilution. Every aliquot drawn from a 10 mg / 10 mg blend contains equal masses of each.
10 mg / 10 mg blend vial (20 mg total peptide)
| Bacteriostatic water added | BPC-157 | TB-500 | Total peptide | Each component per 0.1 mL (10 units) |
|---|---|---|---|---|
| 1 mL | 10 mg/mL | 10 mg/mL | 20 mg/mL | 1 mg |
| 2 mL | 5 mg/mL | 5 mg/mL | 10 mg/mL | 0.5 mg |
| 2.5 mL | 4 mg/mL | 4 mg/mL | 8 mg/mL | 0.4 mg |
| 4 mL | 2.5 mg/mL | 2.5 mg/mL | 5 mg/mL | 0.25 mg |
| 5 mL | 2 mg/mL | 2 mg/mL | 4 mg/mL | 0.2 mg |
5 mg / 5 mg blend vial (10 mg total peptide)
| Bacteriostatic water added | BPC-157 | TB-500 | Total peptide | Each component per 0.1 mL (10 units) |
|---|---|---|---|---|
| 1 mL | 5 mg/mL | 5 mg/mL | 10 mg/mL | 0.5 mg |
| 2 mL | 2.5 mg/mL | 2.5 mg/mL | 5 mg/mL | 0.25 mg |
| 2.5 mL | 2 mg/mL | 2 mg/mL | 4 mg/mL | 0.2 mg |
| 5 mL | 1 mg/mL | 1 mg/mL | 2 mg/mL | 0.1 mg |
Separate single-peptide vials
| Vial | Target concentration | Diluent to add | Peptide per 0.1 mL (10 units) |
|---|---|---|---|
| BPC-157, 5 mg | 2.5 mg/mL | 2 mL | 0.25 mg |
| BPC-157, 10 mg | 5 mg/mL | 2 mL | 0.5 mg |
| BPC-157, 10 mg | 2 mg/mL | 5 mL | 0.2 mg |
| TB-500, 5 mg | 2.5 mg/mL | 2 mL | 0.25 mg |
| TB-500, 10 mg | 5 mg/mL | 2 mL | 0.5 mg |
| TB-500, 10 mg | 2 mg/mL | 5 mL | 0.2 mg |
Example calculations
Example 1: blend vial. A 10 mg / 10 mg blend is reconstituted with 2 mL. BPC-157 = 10 ÷ 2 = 5 mg/mL; TB-500 = 10 ÷ 2 = 5 mg/mL. A scratch-assay plate needs 0.25 mg of each peptide per condition. Volume = 0.25 ÷ 5 = 0.05 mL (50 µL, or 5 units on a U-100 laboratory syringe). The vial provides 2 ÷ 0.05 = 40 conditions.
Example 2: molar check. In that same stock, BPC-157 at 5 mg/mL is about 3.5 mM, while TB-500 at 5 mg/mL is about 1.0 mM. If an experimental design calls for equimolar exposure, a mass-matched blend will not deliver it; reconstitute separate vials instead.
Example 3: combining separate vials. Mixing equal volumes of two stocks halves both concentrations. One millilitre of BPC-157 at 5 mg/mL plus one millilitre of TB-500 at 5 mg/mL yields 2 mL containing 2.5 mg/mL of each. To finish at 5 mg/mL of each, start with both stocks at 10 mg/mL.
Single-peptide protocols are covered in BPC-157 reconstitution and storage and TB-500 reconstitution and storage.
Blend vial or separate vials?
| Consideration | Pre-blended vial | Separate vials |
|---|---|---|
| Ratio | Fixed at manufacture (e.g., 1:1 by mass) | Any ratio, including equimolar |
| Bench steps | One reconstitution | Two reconstitutions plus mixing |
| Contamination opportunities | Fewer vial entries | More vial entries |
| Single-agent controls | Requires separate material | Built in |
| Stability clock | Set by the less stable component | Each peptide tracked independently |
| Documentation | COA should report both components | One COA per peptide |
A broader discussion is in peptide blends and research stacks. Three- and four-component blends follow the same per-component math; see KLOW stack reconstitution and storage.
Post-reconstitution storage
| Form | Temperature | Light | Working time frame | Notes |
|---|---|---|---|---|
| Lyophilized blend, sealed | −20 °C | Dark | Long term; follow COA retest date | Keep dry; equilibrate before opening |
| Lyophilized blend, sealed | 2–8 °C | Dark | Short term (weeks) | Fine between delivery and use |
| Blend in bacteriostatic water | 2–8 °C | Dark | Up to 28 days | TB-500 methionine oxidation is the limiting chemistry |
| Blend in PBS or unpreserved water | 2–8 °C | Dark | Same day | Single use only |
| Single-use frozen aliquots | −20 °C or below | Dark | Per lab SOP | Thaw once; do not refreeze |
General principles are set out in storing research peptides, and the diluent's own limits in does bacteriostatic water expire?
Common reconstitution errors and how to avoid them
| Error | Consequence | Prevention |
|---|---|---|
| Labelling only the total (e.g., "10 mg/mL") | Ambiguity about per-component concentration | Write each component's mg/mL on the label |
| Squirting diluent onto the cake | Foam and slow, uneven dissolution | Run liquid down the vial wall |
| Vortexing or shaking | Foaming; aggregation risk for TB-500 | Gentle swirling only |
| Opening a cold vial | Condensation on a hygroscopic cake | Equilibrate 15–20 minutes |
| Assuming equal mass means equal moles | Mis-specified molar exposure | Convert with molecular weights |
| Using bacteriostatic water in cell culture | Benzyl alcohol cytotoxicity confounds results | Use PBS or medium, prepared fresh |
| Leaving large headspace for weeks | Methionine oxidation in TB-500 | Aliquot; minimize air exchange |
| Unlabelled aliquots | Loss of traceability | Label every tube at the time of filling |
| Mixing two stocks without recalculating | Both concentrations silently halved | Recalculate after any combination |
Verifying a blend before you reconstitute
A blend is harder to characterize than a single peptide, so the documentation deserves a closer look. The COA should identify both components, report the mass of each per vial, and show an HPLC trace in which two principal peaks are resolved, with mass-spectrometry confirmation for each (about 1,419 Da for BPC-157 and about 4,963 Da for thymosin β4). A single purity number with no chromatogram does not demonstrate that both peptides are present in the stated amounts. See BPC-157 purity testing, TB-500 purity testing and the COA library.
V8 Peptides supplies the BPC-157 + TB-500 blend in a 10 mg / 10 mg vial with batch documentation, alongside the individual peptides for single-agent controls.
References
- Huff T, Müller CSG, Otto AM, Netzker R, Hannappel E. β-Thymosins, small acidic peptides with multiple functions. Int J Biochem Cell Biol. 2001;33(3):205–220.
- Chang CH, Tsai WC, Lin MS, Hsu YH, Pang JHS. The promoting effect of pentadecapeptide BPC 157 on tendon healing involves tendon outgrowth, cell survival, and cell migration. J Appl Physiol. 2011;110(3):774–780.
- Li S, Schöneich C, Borchardt RT. Chemical instability of protein pharmaceuticals: mechanisms of oxidation and strategies for stabilization. Biotechnol Bioeng. 1995;48(5):490–500.
- Manning MC, Chou DK, Murphy BM, Payne RW, Katayama DS. Stability of protein pharmaceuticals: an update. Pharm Res. 2010;27(4):544–575.
- United States Pharmacopeia. General Chapter <797> Pharmaceutical Compounding—Sterile Preparations. USP–NF.
- United States Pharmacopeia. General Chapter <51> Antimicrobial Effectiveness Testing. USP–NF.
- Hospira, Inc. (Pfizer). Bacteriostatic Water for Injection, USP — package insert. DailyMed, U.S. National Library of Medicine.
Frequently asked questions
How much bacteriostatic water do I add to a 10 mg / 10 mg BPC-157 + TB-500 blend?
2 mL is the most convenient volume: it gives 5 mg/mL of each peptide (10 mg/mL total), so every 0.1 mL contains 0.5 mg of BPC-157 and 0.5 mg of TB-500. Use 4 mL for 2.5 mg/mL of each if the vial has the capacity.
How do I calculate concentration for a blend?
Work out each component separately: component milligrams divided by millilitres of diluent. The total peptide concentration is the sum. The calculator can be run once per component.
What diluent should be used to reconstitute BPC-157 for research?
Bacteriostatic water for multi-use stock solutions; unpreserved sterile water or PBS for single-session or cell-based work. BPC-157 is highly water-soluble and needs no co-solvent.
What diluent should be used to reconstitute TB-500 for research?
The same options apply. Bacteriostatic water is standard for multi-use stock. For cell culture, use sterile PBS or medium prepared fresh, since benzyl alcohol is toxic to cultured cells.
Should I vortex BPC-157 or TB-500 during reconstitution?
No. Gentle swirling is sufficient for both. Vortexing introduces foam and shear at the air–liquid interface, which is a particular concern for the 43-residue TB-500.
How long is a reconstituted BPC-157 + TB-500 blend stable?
In bacteriostatic water at 2–8 °C and protected from light, apply a 28-day in-use limit. TB-500 is the more labile component because its methionine residue can oxidize, so quantitative studies benefit from fresher stock or single-use frozen aliquots.
Can I mix separately reconstituted BPC-157 and TB-500 in one vial?
Yes, using aseptic technique, but recalculate afterwards. Combining equal volumes halves the concentration of each peptide. Label the mixed vial with both final concentrations.
Is a 1:1 blend by mass also 1:1 by moles?
No. BPC-157 (about 1,419.5 g/mol) is roughly 3.5 times lighter than TB-500 (about 4,963 g/mol), so equal masses contain about 3.5 times more BPC-157 molecules.
Can I freeze the reconstituted blend?
Only as single-use aliquots in low-bind tubes, thawed once. Repeated freeze–thaw cycles degrade peptides and shift concentrations.
Why does my blend look slightly foamy after adding diluent?
The diluent was probably added quickly or the vial was agitated. Stand it upright for several minutes and the foam will settle. A clear solution underneath is fine to use.
How do I convert a blend concentration to units on a lab syringe?
On a U-100 scale, 1 unit is 0.01 mL. At 5 mg/mL of each component, 10 units (0.1 mL) holds 0.5 mg of each peptide and 5 units holds 0.25 mg of each.