GLOW and KLOW blends: BPC-157, TB-500, GHK-Cu and KPV in research

GLOW and KLOW are two ready-to-use research blends, each supplied as a lyophilised powder in a single vial. Both combine BPC-157, TB-500 and GHK-Cu, and KLOW also contains KPV. At first glance the two products look alike, so it is worth examining their composition before planning a study. This overview explains how the blends differ, how to read their components and why the TB-500 fragment (17-23) appears in this set.

Composition of both blends

Both blends are research reagents supplied as a lyophilisate. The table below shows exactly what is in one vial.

Component	GLOW	KLOW
BPC-157	10 mg	10 mg
TB-500	10 mg	10 mg
GHK-Cu	50 mg	50 mg
KPV	none	10 mg

The difference is therefore a single component, but it matters for study design: KLOW is GLOW with the tripeptide KPV added. Because the other three components are present in identical amounts, comparing the two blends makes it possible to isolate the contribution of KPV.

The composition is fixed, and every vial matches the same specification. There is no need to measure components separately, which reduces the number of variables when preparing a solution. It also turns several decisions into one: whether a study requires all components at once or only selected ones. When a single component is needed, it is available on its own product page.

BPC-157: a pentadecapeptide of 15 residues

BPC-157 is a pentadecapeptide, a chain of 15 amino acid residues. Its sequence is described as a fragment of a protein found in gastric juice. In preclinical models its links to the nitric oxide system and to the expression of growth factors have been described. In vitro studies have reported effects on the migration and proliferation of fibroblasts and endothelial cells, and in animal models an association with the formation of new blood vessels. Specific results should be verified directly in the primary sources, and when reading experimental descriptions it is worth paying attention to the model, concentration and culture conditions. A short chain is also convenient for comparisons with longer peptides, because it is easier to describe and analyse within the same system. The peptide is also available separately in the BPC-157 shop.

TB-500 and the 17-23 fragment

TB-500 is a synthetic fragment of the naturally occurring protein thymosin beta-4, which binds actin. Actin forms the cytoskeleton, the internal structure of the cell that determines its shape and movement. The 17-23 fragment, sold as TB-500 Fragment, has the sequence Ac-LKKTETQ: seven amino acid residues with an acetylated N-terminus. This region of thymosin beta-4 is responsible for actin binding, so in research it serves as a tool for questions about cytoskeletal dynamics. In vitro studies have described such a peptide influencing the balance between actin monomers and filaments, which correlates with cell motility in culture. The fragment also has a practical side: its short sequence makes it easier to control in solution and to repeat the preparation across batches. More about the fragment itself is available on the TB-500 Fragment (17-23) page.

GHK-Cu: a tripeptide with a copper ion

GHK-Cu is the tripeptide glycyl-histidyl-lysine bound to a copper(II) ion. It is described as a compound that occurs naturally in plasma. It has been studied in cell cultures for its effects on collagen synthesis and extracellular matrix proteins. In both blends it is the heaviest component at 50 mg per vial, so its dissolution and even mixing into the solution should be planned from the outset. When recording composition, always give the form as GHK-Cu, meaning the tripeptide bound to copper, not copper alone.

KPV: the fourth component of KLOW

KPV is the tripeptide lysine-proline-valine (Lys-Pro-Val), the C-terminal fragment of alpha-MSH, a naturally occurring peptide from the melanocortin family. Its small, well-defined molecule is convenient to analyse and to handle in solution. The short sequence also simplifies quality control, since mass and purity are easier to confirm by HPLC and MS. In vitro and animal model studies have described KPV’s influence on the inflammatory response, including the production of pro-inflammatory cytokines. Some reports mention activity linked to NF-κB, a key regulator of inflammatory signalling. Models of gastrointestinal mucosal inflammation are among the areas in which KPV is studied. This component is what distinguishes KLOW from GLOW. KPV on its own is available in the KPV shop.

GLOW or KLOW: choosing for your research question

The choice depends on what the team wants to examine. If the question concerns extracellular matrix remodelling, collagen synthesis and vessel formation, GLOW already contains BPC-157, TB-500 and GHK-Cu, without an additional inflammatory component. If the project also includes analysis of inflammatory signalling, KLOW provides the same set plus KPV. Both blends are a good starting point for comparisons, because they differ by a single component. It is also worth recording in the protocol which result would be surprising before the first measurement series begins.

A simple design sets the two products up as two comparison arms. The difference between the arms then shows how KPV changes the picture in a given model. Such a design requires equal solvent volumes, the same solution preparation procedure and a shared control group. Without these, the result will not be readable.

Purchase and shipping

GLOW and KLOW are available in the MOLEVIA shop. Every batch has a purity of at least 99%, confirmed by HPLC, and molecular mass is confirmed by MS. Products are shipped as a lyophilisate in tightly sealed vials, and dispatch takes place within 24 hours. In Poland, parcels are delivered to an InPost parcel locker, and across Europe shipments are handled by the DPD courier.

Working in the laboratory

Store the lyophilisate at -20 °C, tightly closed and protected from moisture and light. Before opening a vial, let it reach room temperature to limit condensation of water vapour inside. The solvent is chosen by the study protocol. Bacteriostatic water is the most common choice, and some protocols use water with added acetic acid. Fix the solvent before starting a series, because a change during the work can alter conditions and make results harder to compare. After reconstitution, keep the solution at 2-8 °C, avoid repeated freezing and thawing, and divide it into working aliquots.

Because the vial contains several components, the concentration of each depends on the solvent volume. Run the calculation in the concentration calculator before the first pipetting. Also record the batch number and reconstitution date in the laboratory log, since this makes experiments easier to repeat and differences between measurement series easier to explain. If the solution is divided into aliquots, describe each one separately, with the date of first opening and the number of freeze-thaw cycles. That way, if an unexpected result appears, it is immediately clear which aliquot was used.