This article is for laboratory and research information only. All products referenced are supplied strictly for research use and are not for human or veterinary use. Last reviewed: October 2026.
Quick answer: Glow and Klow are research peptide blends supplied as ready-mixed pens. Glow combines three peptides: BPC-157, TB-500 and GHK-Cu (70mg in total). Klow contains the same three plus KPV (80mg in total). The only difference is the added KPV. Both are sold in the UK for laboratory research use only.
Glow vs Klow at a glance
| Glow 70mg | Klow 80mg | |
|---|---|---|
| GHK-Cu | 50mg | 50mg |
| BPC-157 | 10mg | 10mg |
| TB-500 | 10mg | 10mg |
| KPV | None | 10mg |
| Total | 70mg | 80mg |
| Format | Ready-mixed pen | Ready-mixed pen |
What is in the Glow blend?
Glow brings together three of the most widely studied research peptides:
- GHK-Cu: a copper-binding tripeptide studied in laboratory models of collagen synthesis and extracellular matrix remodelling. See our GHK-Cu guide.
- BPC-157: a 15-amino-acid synthetic peptide studied in preclinical tissue repair and angiogenesis models. See our BPC-157 guide.
- TB-500: a synthetic peptide based on Thymosin Beta-4, studied in cell migration and actin regulation research. See BPC-157 vs TB-500.
What does Klow add?
Klow contains everything in Glow plus KPV, a three-amino-acid peptide (Lys-Pro-Val) taken from the end of alpha-melanocyte-stimulating hormone. KPV is studied in laboratory models of inflammatory signalling, including NF-κB pathway activity and epithelial cell models.
The "K" in Klow is commonly taken to refer to that added KPV.
Why study peptides as a blend?
The peptides in these blends are thought to act through different pathways, so researchers sometimes examine them together to see whether their effects in laboratory models are complementary. A blend supplies them in one fixed ratio, at a known concentration, without the lab preparing and combining several solutions.
Research on combinations is much less developed than research on each peptide alone, and most of the evidence for every component comes from cell and animal models rather than human clinical trials.
Glow or Klow: which do labs choose?
It depends on the research question. If inflammatory signalling pathways are part of the study design, Klow includes KPV for that purpose. If they are not, Glow covers the same three core peptides without it. Labs that want to study the components separately can use the single-peptide pens instead, such as the GHK-Cu, BPC-157, TB500 and KPV pens.
Why are the blends blue?
Both blends contain GHK-Cu, and its bound copper ion gives the solution a blue tint. The shade can vary between batches without affecting purity.
What to check on a blend CoA
- Every component identified, not just a single purity figure for the whole blend.
- The amount of each peptide matching the stated ratio.
- HPLC and mass spectrometry from a third-party lab.
- A batch number that matches your pen.
See how to read a peptide CoA for more.
Storage
Like all pre-filled pens, Glow and Klow should be kept refrigerated at 2–8°C, protected from light, and not frozen. See our guide to pre-filled research pens and our storage guide.
Glow vs Klow FAQ
What is the difference between Glow and Klow?
Klow contains an extra 10mg of KPV. Otherwise the two blends are the same: GHK-Cu 50mg, BPC-157 10mg and TB-500 10mg.
Are Glow and Klow peptides or brand names?
They are names for blends of several established research peptides, not single compounds.
Where can I find Glow and Klow in the UK?
Both are available as ready-mixed pens: the Glow 70mg Pen and the Klow 80mg Pen, each supplied for laboratory research use only.