Quick answer: GLOW, KLOW and Wolverine are vendor nicknames for three co-lyophilized peptide blends built from overlapping components. The Wolverine stack is the two-peptide base: BPC-157 and TB-500. GLOW adds the copper peptide GHK-Cu to that pair. KLOW adds a fourth component, the tripeptide KPV, on top of GLOW. Each step up adds a distinct research pathway and one more variable to track at the bench.
This comparison sets out what is in each vial, what each component is studied for in preclinical models, and how the concentration math differs. For laboratory research use only; not for human consumption.
What is in each blend?
None of these names is a scientific term. They are shorthand for fixed-ratio mixtures that are freeze-dried together so that one reconstitution step yields every component in a single solution.
| Blend | Components | Total peptide per vial | Appearance |
|---|---|---|---|
| Wolverine stack | BPC-157 10 mg + TB-500 10 mg | 20 mg (1:1) | White cake; colorless solution |
| GLOW stack | GHK-Cu 50 mg + BPC-157 10 mg + TB-500 10 mg | 70 mg (5:1:1) | Blue cake; blue solution |
| KLOW stack | GHK-Cu + KPV + BPC-157 + TB-500 | 80 mg | Blue cake; blue solution |
The 80 mg KLOW format is conventionally built as the GLOW composition plus 10 mg of KPV. Per-component identity for any given lot should be confirmed on the batch certificate, available from the COA page, before calculating concentrations.
The four components
Understanding the blends starts with the individual peptides, since the published literature addresses them one at a time.
| Component | What it is | Approx. molecular weight | Main preclinical research themes | Found in |
|---|---|---|---|---|
| BPC-157 | 15-residue synthetic peptide | ≈ 1,419.5 g/mol | Tendon, ligament and gastrointestinal models in rodents; angiogenic signaling | Wolverine, GLOW, KLOW |
| TB-500 | 43-residue thymosin beta-4 sequence | ≈ 4,963 g/mol | Actin sequestration, cell migration, wound-closure assays | Wolverine, GLOW, KLOW |
| GHK-Cu | Tripeptide–copper(II) complex | ≈ 404 g/mol (complex) | Fibroblast, collagen and extracellular-matrix studies | GLOW, KLOW |
| KPV | C-terminal tripeptide of α-MSH | ≈ 342 g/mol | NF-κB and inflammation-signaling studies in cell models | KLOW |
BPC-157
BPC-157 is a pentadecapeptide (Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val). Most of its literature comes from rodent work on tendon, ligament, muscle and gastrointestinal tissue models, with mechanistic papers pointing to VEGFR2-linked angiogenic signaling, the nitric oxide system and growth hormone receptor expression in tendon fibroblasts. It is also stocked as a single compound: BPC-157 10 mg.
TB-500
TB-500 corresponds to the thymosin beta-4 sequence, a 43-residue peptide that is the principal G-actin-sequestering molecule in many cell types. Because actin dynamics drive cell movement, it appears in scratch-wound and migration assays with keratinocytes and endothelial cells, as well as in rodent tissue-repair models. A standalone vial is listed as TB-500.
GHK-Cu
GHK (glycyl-histidyl-lysine) is a plasma tripeptide that binds copper(II) with high affinity. In fibroblast cultures it has been reported to increase collagen and glycosaminoglycan synthesis and to alter the expression of matrix-remodeling genes. The copper complex gives the powder and its solutions a characteristic blue color. It is available alone as GHK-Cu, and a fuller profile appears in the GLOW peptide blend overview.
KPV
KPV (Lys-Pro-Val) is residues 11–13 of α-melanocyte-stimulating hormone. In intestinal epithelial and immune cell models it has been reported to reduce NF-κB and MAP kinase activation, and uptake through the PepT1 transporter has been described in colonocyte studies. A separate KPV vial is available for designs that need it as an independent variable.
GLOW vs KLOW vs Wolverine: key differences
Number of pathways under study
The Wolverine stack pairs two peptides whose literatures both centre on soft-tissue repair models but through different mechanisms: growth-factor and vascular signaling for BPC-157, cytoskeletal regulation for TB-500. GLOW layers extracellular-matrix and copper biology on top. KLOW adds melanocortin-derived inflammation signaling. A blend is appropriate when the protocol calls for all of its components together; it is the wrong format when one component needs to be varied on its own.
Mass ratio and molar ratio
Mass ratios and molar ratios diverge sharply in these blends because the components differ more than tenfold in molecular weight. In a Wolverine vial, equal 10 mg masses correspond to about 7.0 µmol of BPC-157 but only about 2.0 µmol of TB-500. In GLOW, 50 mg of GHK-Cu is about 124 µmol, so on a molar basis the copper peptide outnumbers TB-500 roughly sixtyfold. Experiments that report results per mole should state which basis was used.
Copper content
GLOW and KLOW contain a copper(II) complex; Wolverine does not. That matters for assays sensitive to transition metals, for colorimetric readouts where a blue solution may interfere, and for buffers containing strong chelators such as EDTA, which can strip copper from GHK.
Analytical complexity
Every added component adds a peak that must be resolved and assigned on HPLC. A two-peptide blend is comparatively simple to verify; a four-peptide blend containing two very small tripeptides and a 43-residue peptide spans a wide range of retention behavior. The more components in a vial, the more weight the certificate of analysis carries.
Concentration math compared
The rule is the same for every blend: each component's concentration equals its mass divided by the diluent volume. The table uses 2 mL as a common reference volume.
| Blend (+ 2 mL diluent) | Total peptide | GHK-Cu | BPC-157 | TB-500 | KPV |
|---|---|---|---|---|---|
| Wolverine (20 mg) | 10 mg/mL | – | 5 mg/mL | 5 mg/mL | – |
| GLOW (70 mg) | 35 mg/mL | 25 mg/mL | 5 mg/mL | 5 mg/mL | – |
| KLOW (80 mg; 50/10/10/10 configuration) | 40 mg/mL | 25 mg/mL | 5 mg/mL | 5 mg/mL | 5 mg/mL |
Notice that at equal diluent volume the BPC-157 and TB-500 concentrations are identical across all three blends. What changes is the total solute load, which is why GLOW and KLOW are often reconstituted with larger volumes. The calculator handles other volumes, and worked examples appear in BPC-157 + TB-500 blend reconstitution.
Handling and storage
Handling is broadly the same for all three blends:
- Store sealed vials at −20 °C for the long term, or 2–8 °C for the short term, away from light and moisture.
- Let a cold vial reach room temperature before opening to avoid condensation on the cake.
- Add diluent, such as bacteriostatic water, slowly along the glass and swirl until clear. Do not shake or vortex multi-component mixtures.
- Refrigerate the reconstituted solution at 2–8 °C, protect it from light, and aliquot to limit repeated handling.
- Label the vial with each component's concentration, not just the total.
The general principles are set out in storing research peptides and how to mix peptides with bacteriostatic water.
What the literature does and does not cover
It is worth being precise about the evidence base. Each of the four components has its own body of preclinical publications. Published studies that test these specific fixed-ratio combinations as blends, and compare them with the individual components, are lacking. Claims of synergy between the components are hypotheses drawn from non-overlapping mechanisms, not demonstrated findings. A laboratory using a blend should plan single-component controls if the aim is to attribute an observed effect to a particular peptide or to an interaction between them.
Practical considerations before choosing a blend
- Coupled concentrations. In any co-lyophilized vial, setting the amount of one component sets the amounts of all the others. With GLOW, an aliquot containing 1 mg of GHK-Cu always carries 200 µg each of BPC-157 and TB-500.
- Solute load. A GLOW or KLOW vial holds three and a half to four times the peptide mass of a Wolverine vial. Larger diluent volumes keep the solution easier to dissolve and pipette accurately.
- Buffer compatibility. The copper complex in GLOW and KLOW is sensitive to chelators and to strongly reducing conditions; Wolverine has no such restriction.
- Controls. A design that reports a blend-level effect is strengthened by parallel arms using each single component at the matching concentration.
- Record keeping. Note the lot number, diluent volume and each calculated concentration at the time of reconstitution, so that results can be traced back to a defined solution.
Which blend fits which study design?
- Wolverine: the simplest format, suited to protocols focused on BPC-157 and TB-500 together, to assays where copper would interfere, and to work where analytical verification should stay straightforward.
- GLOW: suited to matrix-focused models, such as fibroblast and collagen studies, in which the copper peptide is wanted alongside the two repair-signaling peptides.
- KLOW: suited to multi-pathway designs that also examine inflammation signaling, where KPV is a required component.
- Separate vials: the right choice whenever any one component must be titrated independently or omitted as a control.
All three blends and their individual components are listed in the shop. Background on the category is available in what research peptides are.
Frequently asked questions
What is the difference between GLOW and KLOW?
KLOW contains everything in GLOW (GHK-Cu, BPC-157 and TB-500) plus a fourth peptide, KPV. GLOW is a 70 mg three-component vial; KLOW is an 80 mg four-component vial.
Is the Wolverine stack just GLOW without GHK-Cu?
In terms of composition, yes. Wolverine contains 10 mg each of BPC-157 and TB-500, the same two peptides and masses found in GLOW, without the 50 mg of copper peptide. It therefore reconstitutes to a colorless solution instead of a blue one.
Why are GLOW and KLOW blue?
The color comes from the copper(II) ion bound by GHK. It is expected and is not a sign of contamination. A Wolverine vial, which has no copper complex, should be white as a powder and clear and colorless in solution.
Has any study compared the three blends directly?
No peer-reviewed study comparing these fixed-ratio blends with each other, or with their individual components, is available. The supporting literature is component-level, so blend-level conclusions require the researcher's own controls.