If you have spent any time in research-peptide catalogs, you have seen the nicknames. GLOW. KLOW. They look like the name of a molecule. They are not. They are catalog shorthand for multi-component blends, and the shorthand is not standardized the way a CAS number is.
That is the whole problem, and it is also why the comparison is worth writing down. Two three-letter labels can hide different recipes. If you are trying to identify material for a bench protocol, or to read a certificate of analysis without guessing, you need the component list, not the nickname.
This article uses the common marketing names as catalogs print them. GLOW is the three-component blend of BPC-157, TB-500, and GHK-Cu. KLOW is the three-component blend of BPC-157, GHK-Cu, and KPV. Those are names, not INN or USAN designations. A lot-specific COA is still the record for the vial in front of you.
GLOW vs KLOW at a glance
Catalog name
Usual component list
What the nickname is not
GLOW
BPC-157, TB-500, GHK-Cu
Not a single CAS. Not a cosmetic. Not an official drug name.
KLOW
BPC-157, GHK-Cu, KPV
Not a single CAS. Not a protocol. Not an official drug name.
Shared in both nicknames: BPC-157 and GHK-Cu. The swap is the third component. GLOW lists TB-500. KLOW lists KPV. That is the composition difference the names are meant to flag. It is not a ranking of one blend over the other.
Why the nicknames exist
Research catalogs need a short label for a vial that holds more than one peptide. Writing “BPC-157 / TB-500 / GHK-Cu” on every line of a price list is accurate and ugly. GLOW and KLOW are the market’s attempt at a handle, the same way “Wolverine” is used as a handle for a BPC-157 plus TB-500 mix.
None of those handles is a chemical identifier. There is no CAS registry number for “GLOW” or “KLOW” as a substance, because they are mixtures. Identity lives at the component level:
BPC-157 (Body Protection Compound-157), a synthetic pentadecapeptide, CAS 137525-51-0.
GHK-Cu, the copper(II) complex of glycyl-L-histidyl-L-lysine, CAS 89030-95-5.
KPV, the tripeptide lysyl-prolyl-valine, CAS 67727-97-3.
TB-500, a research-market name (see the naming note below), often listed with a thymosin beta-4-related CAS such as 77591-33-4.
If a label or a blog post uses only the nickname, you still do not know the masses of each component, the counter-ion, or whether a fourth peptide was added. Those facts, when they exist, are on the batch COA.
The four components, as chemistry, not as a story about results
BPC-157 is a 15-residue synthetic peptide. Chemical databases list molecular formula C62H98N16O22 and a sequence commonly written GEPPPGKPADDAGLV. The Zagreb group around Predrag Sikiric published the early gastric pentadecapeptide literature that put this sequence into the research record. It is not FDA-approved as a medicine.
GHK-Cu is not “copper plus a peptide” in the casual sense. It is a coordination complex: the tripeptide Gly-His-Lys bound to copper(II). Loren Pickart and M. Michael Thaler described a plasma tripeptide of that sequence in 1973 in Nature New Biology. Later work characterized the copper complex as a distinct chemical species from the metal-free tripeptide. Confirm on the COA that the tested analyte is the copper complex (CAS 89030-95-5), not free GHK.
KPV is three amino acids: Lys-Pro-Val. Peptide literature describes it as corresponding to residues 11-13 at the C-terminus of alpha-melanocyte-stimulating hormone (alpha-MSH). That is a structural relationship to a parent hormone, not a statement that KPV is alpha-MSH, and not a use instruction.
TB-500 is the messy one, and it is worth slowing down here. In catalogs, “TB-500” is a nickname, not a single agreed sequence. Some listings treat it as related to thymosin beta-4, a 43-residue actin-binding peptide (CAS 77591-33-4 is the Tβ4-related number often used). Other sources use “TB-500” for a short synthetic fragment from the thymosin beta-4 sequence (the acetylated heptapeptide Ac-LKKTETQ appears in that discussion). Those are not the same molecule. A mass on a COA that matches a ~5 kDa species is not describing a ~900 Da heptapeptide, and the reverse is also true. For a GLOW vial, “TB-500” on the marketing line is not enough. The COA has to say which species was identified.
The names are not a standard
Here is the part most comparison posts skip. GLOW and KLOW are not controlled vocabulary. Some catalogs keep KLOW as the three-component set above. Some listings use KLOW for a four-component mix that adds TB-500 on top of BPC-157, GHK-Cu, and KPV. That is not a revision of a pharmacopeial monograph. It is different vendors using the same nickname for different recipes.
So a search for “klow peptide” can return pages that are not talking about the same vial. The useful move is boring and reliable: ignore the poetry of the name, read the component table, then match lot numbers. If a COA lists four analytes and the product title lists three, believe the COA for that lot and treat the title as marketing.
Ratios are the same story. There is no official GLOW ratio or KLOW ratio in a pharmacopeia. When a blend COA reports milligrams per component, those milligrams are lot data. They are not a universal recipe, and they are not a reason to prefer one nickname.
How to tell them apart on paper
If you are holding two COAs, the tell is the third (or fourth) line:
BPC-157 + TB-500 + GHK-Cu points at the GLOW marketing name.
BPC-157 + GHK-Cu + KPV points at the KLOW marketing name.
BPC-157 + GHK-Cu + KPV + TB-500 is a four-component mix. Some sellers still print KLOW on that vial. The nickname has then stopped being a unique identifier.
HPLC purity on a blend also needs a closer look than a single-analyte vial. A single “99%” number can mean different things: purity of each component after separation, or a less informative bulk figure. A serious blend COA identifies each peptide (often by mass spectrometry) and reports how much of each is in the labeled vial. For the method-level reading of those fields, see how to read a peptide COA.
What this comparison is not
It is not a guide to which blend to pick. It is not a description of outcomes, and it is not a protocol. GLOW and KLOW are research-market names for lyophilized mixtures sold as laboratory reagents. They are not cosmetics, not medicines, and not a substitute for a defined single-analyte standard when your assay needs one peptide at a time.
Component overviews, written as reference pages rather than catalog copy, are here:
Pickart L, Thaler MM. Tripeptide in human serum which prolongs survival of normal liver cells and stimulates growth in neoplastic liver. Nat New Biol. 1973;243:85-87.
PubChem and chemical registry listings for BPC-157, CAS 137525-51-0.
PubChem and chemical registry listings for GHK-Cu, CAS 89030-95-5.
PubChem and chemical registry listings for KPV (Lys-Pro-Val), CAS 67727-97-3.
Thymosin beta-4 identity in the biochemical literature (CAS 77591-33-4). Confirm whether a given “TB-500” lot matches Tβ4 or a fragment by the COA mass and method, not by the nickname.
For laboratory research only. Not for human or veterinary use. Not intended to diagnose, treat, cure, or prevent any disease.
GLOW vs KLOW Peptide: Composition and Naming
If you have spent any time in research-peptide catalogs, you have seen the nicknames. GLOW. KLOW. They look like the name of a molecule. They are not. They are catalog shorthand for multi-component blends, and the shorthand is not standardized the way a CAS number is.
That is the whole problem, and it is also why the comparison is worth writing down. Two three-letter labels can hide different recipes. If you are trying to identify material for a bench protocol, or to read a certificate of analysis without guessing, you need the component list, not the nickname.
This article uses the common marketing names as catalogs print them. GLOW is the three-component blend of BPC-157, TB-500, and GHK-Cu. KLOW is the three-component blend of BPC-157, GHK-Cu, and KPV. Those are names, not INN or USAN designations. A lot-specific COA is still the record for the vial in front of you.
GLOW vs KLOW at a glance
Shared in both nicknames: BPC-157 and GHK-Cu. The swap is the third component. GLOW lists TB-500. KLOW lists KPV. That is the composition difference the names are meant to flag. It is not a ranking of one blend over the other.
Why the nicknames exist
Research catalogs need a short label for a vial that holds more than one peptide. Writing “BPC-157 / TB-500 / GHK-Cu” on every line of a price list is accurate and ugly. GLOW and KLOW are the market’s attempt at a handle, the same way “Wolverine” is used as a handle for a BPC-157 plus TB-500 mix.
None of those handles is a chemical identifier. There is no CAS registry number for “GLOW” or “KLOW” as a substance, because they are mixtures. Identity lives at the component level:
If a label or a blog post uses only the nickname, you still do not know the masses of each component, the counter-ion, or whether a fourth peptide was added. Those facts, when they exist, are on the batch COA.
The four components, as chemistry, not as a story about results
BPC-157 is a 15-residue synthetic peptide. Chemical databases list molecular formula C62H98N16O22 and a sequence commonly written GEPPPGKPADDAGLV. The Zagreb group around Predrag Sikiric published the early gastric pentadecapeptide literature that put this sequence into the research record. It is not FDA-approved as a medicine.
GHK-Cu is not “copper plus a peptide” in the casual sense. It is a coordination complex: the tripeptide Gly-His-Lys bound to copper(II). Loren Pickart and M. Michael Thaler described a plasma tripeptide of that sequence in 1973 in Nature New Biology. Later work characterized the copper complex as a distinct chemical species from the metal-free tripeptide. Confirm on the COA that the tested analyte is the copper complex (CAS 89030-95-5), not free GHK.
KPV is three amino acids: Lys-Pro-Val. Peptide literature describes it as corresponding to residues 11-13 at the C-terminus of alpha-melanocyte-stimulating hormone (alpha-MSH). That is a structural relationship to a parent hormone, not a statement that KPV is alpha-MSH, and not a use instruction.
TB-500 is the messy one, and it is worth slowing down here. In catalogs, “TB-500” is a nickname, not a single agreed sequence. Some listings treat it as related to thymosin beta-4, a 43-residue actin-binding peptide (CAS 77591-33-4 is the Tβ4-related number often used). Other sources use “TB-500” for a short synthetic fragment from the thymosin beta-4 sequence (the acetylated heptapeptide Ac-LKKTETQ appears in that discussion). Those are not the same molecule. A mass on a COA that matches a ~5 kDa species is not describing a ~900 Da heptapeptide, and the reverse is also true. For a GLOW vial, “TB-500” on the marketing line is not enough. The COA has to say which species was identified.
The names are not a standard
Here is the part most comparison posts skip. GLOW and KLOW are not controlled vocabulary. Some catalogs keep KLOW as the three-component set above. Some listings use KLOW for a four-component mix that adds TB-500 on top of BPC-157, GHK-Cu, and KPV. That is not a revision of a pharmacopeial monograph. It is different vendors using the same nickname for different recipes.
So a search for “klow peptide” can return pages that are not talking about the same vial. The useful move is boring and reliable: ignore the poetry of the name, read the component table, then match lot numbers. If a COA lists four analytes and the product title lists three, believe the COA for that lot and treat the title as marketing.
Ratios are the same story. There is no official GLOW ratio or KLOW ratio in a pharmacopeia. When a blend COA reports milligrams per component, those milligrams are lot data. They are not a universal recipe, and they are not a reason to prefer one nickname.
How to tell them apart on paper
If you are holding two COAs, the tell is the third (or fourth) line:
HPLC purity on a blend also needs a closer look than a single-analyte vial. A single “99%” number can mean different things: purity of each component after separation, or a less informative bulk figure. A serious blend COA identifies each peptide (often by mass spectrometry) and reports how much of each is in the labeled vial. For the method-level reading of those fields, see how to read a peptide COA.
What this comparison is not
It is not a guide to which blend to pick. It is not a description of outcomes, and it is not a protocol. GLOW and KLOW are research-market names for lyophilized mixtures sold as laboratory reagents. They are not cosmetics, not medicines, and not a substitute for a defined single-analyte standard when your assay needs one peptide at a time.
Component overviews, written as reference pages rather than catalog copy, are here:
References
For laboratory research only. Not for human or veterinary use. Not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed: 2026-10-14