Last reviewed: October 2026 · Cleared Peptides research team
Research use only. GLOW vs KLOW Peptide Blends: Research Comparison is supplied for laboratory research. It is not a drug, food, cosmetic, or dietary supplement. It is not FDA-approved. It is not for human or veterinary administration. This page does not give a dose or a method of administration. A study cited on this page describes that study’s own test article. It does not make this lot an approved medicine. To check a fact, open the PubMed or DOI link, confirm the authors and year, and match the paper’s compound name, CAS number, or sequence to the specification table. The full method is on the research desk page. Identity and purity for a lot are only what that lot’s certificate of analysis reports. An HPLC percentage is not a sterility result and not an endotoxin result unless the certificate prints those tests.
GLOW and KLOW are pre-combined research blends built around three widely studied compounds. KLOW adds a fourth — the tripeptide KPV. This page compares their components.
GLOW and KLOW Components
| GLOW components | BPC-157 · GHK-Cu · TB-500 (Thymosin Beta-4) |
|---|---|
| KLOW components | BPC-157 · GHK-Cu · TB-500 · KPV |
| CAS numbers | 137525-51-0 · 89030-95-5 · 77591-33-4 · 67727-97-3 (KPV) |
| Form | Single lyophilized vial per blend |
Component Comparison
| Component | Description | GLOW | KLOW |
|---|---|---|---|
| BPC-157 | 15-aa gastric-protein fragment | ✓ | ✓ |
| GHK-Cu | Copper tripeptide | ✓ | ✓ |
| TB-500 | 43-aa actin-binding peptide | ✓ | ✓ |
| KPV | α-MSH C-terminal tripeptide | — | ✓ |
Learn About Each Component
BPC-157 · TB-500 · GHK-Cu · KPV · BPC-157 vs TB-500
This summary describes laboratory research only and makes no claim about effects in humans or animals.
Purity Testing and Storage
Every lot of GLOW and KLOW supplied by Cleared Peptides is tested by an independent laboratory for identity and purity (or composition, for multi-component preparations), and the lot Certificate of Analysis is published on our COA page. Store the lyophilized blends at −20 °C, sealed, dry and protected from light. Allow the vial to reach room temperature before opening and minimize freeze–thaw cycles. Handle according to your institution’s chemical-hygiene procedures.
Research materials referenced in this guide
Analytical testing notes for GLOW vs KLOW Peptide Blends
GLOW vs KLOW Peptide Blends is identified in this guide as CAS 137525-51-0 · 89030-95-5 · 77591-33-4 · 67727-97-3 (KPV). An identity test compares a measurement with those values. A mass spectrum is the usual measurement for a peptide. FTIR, when a certificate uses it, is a supporting infrared fingerprint and is less specific for closely related sequences.
This page compares more than one component. A single purity percentage is ambiguous unless the certificate says whether each component was resolved, identified, and quantified. Identity and content should be traceable to each named material. A chromatogram with several intentional peaks is expected; those peaks are not automatically impurities.
HPLC purity for this material is an area-percent result at the wavelength and gradient the laboratory states, commonly ultraviolet detection near 214 nm on a reversed-phase column. The instrument is a gradient pump, injector, column oven, and UV or diode-array detector. That percentage is not the number of milligrams in the vial. Water, acetate, trifluoroacetate, and other UV-silent material can dominate the gross weight while the purity figure stays high. Net peptide content, from an assay or amino-acid analysis, is the separate result to read when the certificate reports it.
A sterility test and an endotoxin test are not included in a chemical purity result. The compendial sterility test is a culture method (USP <71>): membrane filtration or direct inoculation into fluid thioglycollate medium and soybean-casein digest medium, incubated for 14 days. A PCR sterility screen uses a thermal cycler to detect microbial DNA and is a different method. The endotoxin test (USP <85> LAL, or USP <86> recombinant Factor C) reports endotoxin units with an incubating reader or a cartridge reader. Use a result only when that method is printed on the lot certificate. One published example in this catalog states that the report does not cover microbial contamination or endotoxins. The full description of equipment, standards, and how US laboratory accreditation works is in peptide analytical testing. Lot records are on the COA page.
Frequently Asked Questions
What is the difference between GLOW and KLOW?
KLOW contains the same three components as GLOW plus the tripeptide KPV.
Are GLOW and KLOW for human use?
No. Cleared Peptides supplies GLOW and KLOW for laboratory research use only; they are not for human or veterinary use.
Selected References
Peer-reviewed literature on the compounds discussed in this guide, listed as scientific background for laboratory researchers. Citation does not imply endorsement by the authors or any use other than in-vitro research.
- Sikiric P, et al. Stable gastric pentadecapeptide BPC 157-NO-system relation. Curr Pharm Des. 2014;20(7):1126-35. PubMed 23755725 · DOI
- Sikiric P, et al. Brain-gut Axis and Pentadecapeptide BPC 157: Theoretical and Practical Implications. Curr Neuropharmacol. 2016;14(8):857-865. PubMed 27138887 · DOI
- Mehr A, et al. The copper(II)-binding tripeptide GHK, a valuable crystallization and phasing tag for macromolecular crystallography. Acta Crystallogr D Struct Biol. 2020;76(Pt 12):1222-1232. PubMed 33263328 · DOI
- Hureau C, et al. X-ray and solution structures of Cu(II) GHK and Cu(II) DAHK complexes: influence on their redox properties. Chemistry. 2011;17(36):10151-60. PubMed 21780203 · DOI
- Nachmias VT. Small actin-binding proteins: the beta-thymosin family. Curr Opin Cell Biol. 1993;5(1):56-62. PubMed 8448031 · DOI
- Dedova IV, et al. Thymosin beta4 induces a conformational change in actin monomers. Biophys J. 2006;90(3):985-92. PubMed 16272441 · DOI
- Catania A, et al. The neuropeptide alpha-MSH in host defense. Ann N Y Acad Sci. 2000;917:227-31. PubMed 11268348 · DOI
- Ichiyama T, et al. The neuroimmunomodulatory peptide alpha-MSH. Ann N Y Acad Sci. 2000;917:221-6. PubMed 11268347 · DOI
Laboratory note: solubility depends on salt form and solvent. This guide does not state a single solubility figure. Handling of lyophilized material is described in the peptide storage guide.
Research Use Only Notice
This guide is provided for educational and laboratory reference purposes. It summarizes published, primarily in-vitro and structural research literature and does not describe, recommend or imply any use in humans or animals. Products sold by Cleared Peptides are for laboratory research use only; they are not drugs, foods, cosmetics or dietary supplements, are not FDA-approved, and are not intended to diagnose, treat, cure, mitigate or prevent any disease. No dosing, administration or therapeutic information is provided.
