KLOW Blend vs GLOW Blend: Composition Compared (80mg vs 70mg)

For research use only. Not for human or veterinary use.

Quick answer: KLOW and GLOW are catalog names for multi-peptide research blends, not single compounds. As most suppliers list them, GLOW is a 70 mg three-component blend (50 mg GHK-Cu, 10 mg BPC-157 and 10 mg TB-500), and KLOW is the same three components plus 10 mg of the tripeptide KPV, for 80 mg per vial. The only compositional difference is KPV. Because the names aren't formal standards, always confirm a specific lot's components and amounts on its Certificate of Analysis (COA).

KLOW vs GLOW at a glance

KLOW Blend (80 mg)

• GHK-Cu: 50 mg
• BPC-157: 10 mg
• TB-500: 10 mg
• KPV: 10 mg
• Components: four, co-lyophilized as one solid in a sealed vial

GLOW Blend (70 mg)

• GHK-Cu: 50 mg
• BPC-157: 10 mg
• TB-500: 10 mg
• KPV: not included
• Components: three, co-lyophilized as one solid in a sealed vial

These are the label amounts most commonly published for each blend. Some vendors sell variants with different ratios, so the name alone doesn't guarantee a formulation.

What the four components are

Each component is a separate molecule. They are mixed at fixed mass ratios and freeze-dried together; they don't form a single chemical complex.

• GHK-Cu is the copper(II) complex of the tripeptide glycyl-L-histidyl-L-lysine (Gly-His-Lys). PubChem lists it as prezatide copper, CID 71587328, about 402.9 g/mol.
• BPC-157 is a synthetic 15-amino-acid peptide with the sequence GEPPPGKPADDAGLV. PubChem CID 9941957, about 1,419.5 g/mol (free peptide; salt forms such as the acetate weigh more).
• TB-500 is a catalog name tied to thymosin beta-4. Depending on the supplier, it can mean the full-length, 43-amino-acid N-acetylated thymosin beta-4 (about 4,963 g/mol, UniProt P62328) or a short 7-residue fragment, Ac-LKKTETQ. Check the COA to see which one a lot contains.
• KPV is the tripeptide lysine-proline-valine (Lys-Pro-Val), the C-terminal three residues of alpha-melanocyte-stimulating hormone (alpha-MSH). PubChem CID 125672, about 342.4 g/mol.

KPV is the one component in KLOW that GLOW doesn't have. A KLOW COA should name KPV in its identity results; a GLOW COA should not.

Why "80 mg vs 70 mg" isn't the whole comparison

It's tempting to read the totals as "more" or "less" of the same thing. They aren't, for three reasons.

1. Mass fractions change

Adding 10 mg of KPV changes each component's share of the vial:

• In KLOW (80 mg): GHK-Cu is 50/80 = 62.5% of the label mass, and BPC-157, TB-500 and KPV are 12.5% each.
• In GLOW (70 mg): GHK-Cu is 50/70 ≈ 71.4%, and BPC-157 and TB-500 are about 14.3% each.

So at an equal total mass, the shared components are present in different proportions. Any lab calculation needs the per-component amounts, not just the vial total.

2. Mass isn't molecule count

The components range from about 342 g/mol (KPV) to about 4,963 g/mol (full-length thymosin beta-4). Equal milligrams don't mean equal numbers of molecules: a milligram of KPV contains roughly 14 times as many molecules as a milligram of full-length thymosin beta-4. A blend has no single molecular weight, sequence or CAS number, so don't apply one component's formula to the whole vial.

3. The blend names aren't standardized

"KLOW" and "GLOW" are vendor naming conventions, not entries in the scientific literature or a pharmacopeia. Two products sold under the same name can differ in ratios, in which form of TB-500 they contain, or in salt form. The COA, not the name, defines what's in the vial.

How a four-component blend is tested

A blend COA has more work to do than a single-peptide COA, because each component has to be separated and identified on its own.

• Separation: reversed-phase HPLC (RP-HPLC) separates the components into distinct peaks on the chromatogram, one per peptide. See HPLC vs. Mass Spectrometry.
• Identity: mass spectrometry (often LC-MS) confirms that each peak has the expected mass. The wide mass range, from a tripeptide to a 43-residue peptide, makes the components straightforward to tell apart.
• Per-component content: a good blend COA reports a labeled and a measured amount for each component, not only a total.
• Purity vs content: HPLC purity isn't the same as how much peptide is in the vial. See Net Peptide Content vs. HPLC Purity.
• Contaminant screening: look for an endotoxin result (in EU/mL) and a sterility or microbial screen. Not every COA includes them.
• Traceability: the report should carry a report number, batch or lot, test date and the testing lab's name, and you should be able to verify it with the lab.

What the QC Labs KLOW Blend COA shows

Our current KLOW Blend lot was tested by Kovera Labs (report KVR-2026-650D2A, certified July 30, 2026). The report lists:

• Labeled vs measured, per component: GHK-Cu 50 mg / 50.14 mg; KPV 10 mg / 10.49 mg; BPC-157 10 mg / 10.57 mg; TB-500 10 mg / 10.94 mg
• Blend average purity: 99.731% (RP-HPLC, C18 column, detection at 214 nm)
• Blend average net content: 82.14 mg against an 80 mg label
• Identification: LC-MS, matched to the four-component blend
• Endotoxin screen: pass (specification ≤0.5 EU/mL)
• Rapid sterility screen: no microbial growth detected

The chromatogram shows four separated peaks, one each for GHK-Cu, KPV, BPC-157 and TB-500. You can view the full report in our COA Library and check the report number on the lab's own verification page.

Choosing between them for a research protocol

Neither blend is "better." They're different materials, and the choice depends on what a study design calls for:

• If a protocol specifies the three-component GHK-Cu/BPC-157/TB-500 material, KLOW isn't a drop-in substitute, because it introduces a fourth variable (KPV) and changes every component's mass fraction.
• If a protocol specifies the four-component material, confirm KPV appears in the COA's identity results.
• Either way, record the lot number and COA report number with every experiment, and keep the lyophilized powder cold, dry and protected from light. See Lyophilized Peptide Storage and Handling.

Published research on these molecules is preclinical (cell-culture and animal-model studies) and has been carried out component by component. We found no published study that tested the four-component combination as a mixture.

QC Labs KLOW Blend 80mg

QC Labs supplies KLOW Blend 80mg, a four-component lyophilized research blend (GHK-Cu 50 mg, BPC-157 10 mg, TB-500 10 mg, KPV 10 mg), with a third-party COA for the listed lot. We ship from Dallas, TX. For single-component work, we also carry GHK-Cu (50 mg). We don't currently sell a GLOW blend.

References

1. PubChem, National Center for Biotechnology Information. Compound summaries: prezatide copper / GHK-Cu (CID 71587328); BPC-157 (CID 9941957); Lys-Pro-Val / KPV (CID 125672); thymosin beta-4 (CID 16132341). https://pubchem.ncbi.nlm.nih.gov/
2. UniProt Consortium. UniProtKB P62328, thymosin beta-4 (human). https://www.uniprot.org/uniprotkb/P62328
3. Pickart L, Freedman JH, Loker WJ, et al. Growth-modulating plasma tripeptide may function by facilitating copper uptake into cells. Nature. 1980;288(5792):715–717. doi:10.1038/288715a0
4. Esposito S, et al. Synthesis and characterization of the N-terminal acetylated 17–23 fragment of thymosin beta 4 identified in TB-500, a product suspected to possess doping potential. Drug Test Anal. 2012;4(9):733–738. doi:10.1002/dta.1402
5. Kovera Labs. Certificate of Analysis, report KVR-2026-650D2A (KLOW, 80 mg), certified July 30, 2026. Available in the QC Labs COA Library.

Frequently asked questions

What is the difference between KLOW and GLOW? KLOW contains KPV; GLOW doesn't. Both list 50 mg GHK-Cu, 10 mg BPC-157 and 10 mg TB-500, so KLOW totals 80 mg and GLOW totals 70 mg.

What is in KLOW Blend 80mg? GHK-Cu 50 mg, BPC-157 10 mg, TB-500 10 mg and KPV 10 mg, co-lyophilized in one vial. Confirm the amounts on the lot's COA.

Is TB-500 the same as thymosin beta-4? Not always. The name is used for full-length thymosin beta-4 and for a short fragment (Ac-LKKTETQ). The COA should identify which one is present.

Does a blend have one molecular weight? No. Each component has its own molecular weight, from about 342 g/mol (KPV) to about 4,963 g/mol (full-length thymosin beta-4).

How do I know a blend COA is genuine? Check that it lists every component with labeled and measured amounts, then verify the report number on the testing lab's website. See How to Verify a Peptide COA.

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For research use only. Not for human or veterinary use. QC Labs products are laboratory reagents and are not intended to diagnose, treat, cure, or prevent any disease. Nothing in this article describes or suggests human use. See our Research Disclaimer.