What the KLOW blend is
KLOW, the "KLOW peptide" or KLOW peptides blend, is a co-lyophilised preparation of four peptides: GHK-Cu, the copper(II) complex of the tripeptide Gly-His-Lys; BPC-157, the 15-residue fragment of a human gastric protein; TB-500, the N-acetylated seven-residue fragment of thymosin beta-4 carrying its actin-binding motif; and KPV, the tripeptide Lys-Pro-Val that forms the C-terminus of alpha-melanocyte-stimulating hormone. The four are dissolved together in the stated amounts, 50 mg, 10 mg, 10 mg and 10 mg, freeze-dried together in a single vial. The resulting blue powder is a physical mixture at a fixed ratio by mass, not a conjugate; the peptides are not covalently linked and behave independently once in solution.
GHK-Cu dominates by mass and by moles, at roughly 124 micromoles in 50 mg, against about 7 micromoles of BPC-157, 11 of TB-500 and 29 of KPV, whose molecular weight is approximately 342 g/mol. The blend is listed in our blends class.
What you receive
Each vial contains the four peptides as a blue lyophilised powder, sealed with a flip-off cap over a crimped stopper, in the net quantities stated on the label: 50 mg of GHK-Cu, 10 mg of BPC-157, 10 mg of TB-500 and 10 mg of KPV, 80 mg in total. There is no carrier, mannitol or other excipient unless the batch certificate says otherwise. The batch number is printed on the label and matches the certificate in our register. The limitation of a blend is its fixed ratio; a design that needs any component varied independently should use the single-compound vials.
Reading the certificate for a KLOW batch
A four-component certificate needs careful reading. Identity by LC-MS is confirmed for each component: about 340 Da for the GHK tripeptide, since the copper is normally stripped under electrospray conditions and the free peptide is what appears; about 342 Da for KPV; about 1,419 Da for BPC-157; and about 889 Da for TB-500. A good certificate notes the copper dissociation and, where measured, reports copper content separately so that the complex can be confirmed. Purity by reversed-phase HPLC shows four main peaks, and the reported purity is their combined area against all peaks; above 98% is expected for a well-made lot. Net content is reported for the vial as a whole and, where quantified against standards, per component.
The impurities expected are those of the individual peptides, chiefly diketopiperazine from the two tripeptides and deletion sequences from the longer two. Our guide to reading a certificate of analysis includes a blend example, and the copper peptides compared guide discusses the copper-specific points.
Storage and handling
Sealed vials should be kept refrigerated at 2 to 8 °C and protected from light; −20 °C is preferable for storage beyond a few months. GHK-Cu is noticeably hygroscopic and will clump and darken if it absorbs moisture, so allow the vial to reach room temperature before opening and reseal promptly. The powder dissolves readily in water or bacteriostatic water to give a blue solution containing all four peptides. Chelating agents such as EDTA will strip the copper from GHK, so buffers containing them should be avoided, and solutions should be aliquoted and frozen for anything beyond short-term refrigerated use. The storage and stability guide covers solvents, concentrations and freeze-thaw behaviour.