KLOW peptide blend: the four components and the research behind each

In short: KLOW is a lyophilised (freeze-dried) blend of four research peptides in one 80 mg vial: GHK-Cu (50 mg), BPC-157, TB-500 and KPV (10 mg each). Each component has its own cell and animal literature, but no published study has tested the four together. The TGA names BPC-157, GHK-Cu and TB-500 as unapproved peptide products.

KLOW is a trade name for a fixed mixture, not a compound. What exists is four separate bodies of research, one per component, plus one rat study that combined two of them. Each component has its own review: BPC-157, TB-500, GHK-Cu and KPV.

Key facts

Identifiers are from PubChem 1 and UniProt 2. Molecular weights are for the free peptide or complex as PubChem lists it; salt forms, such as acetate, weigh more.

	BPC-157	GHK-Cu	TB-500	KPV
Amount in a KLOW vial	10 mg	50 mg	10 mg	10 mg
Synonyms	BPC 157, BPC157, PL-14736	Prezatide copper, copper tripeptide-1, GHK copper	Thymosin beta-4 acetate, Tβ4	Lys-Pro-Val, alpha-MSH (11-13)
Sequence and length	GEPPPGKPADDAGLV, 15 amino acids	Gly-His-Lys with a bound copper(II) ion, 3 amino acids	Ac-SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES, 43 amino acids, N-terminally acetylated (UniProt P62328)	Lys-Pro-Val, 3 amino acids
Molecular formula	C62H98N16O22	C14H23CuN6O4+	C212H350N56O78S	C16H30N4O4
Molecular weight (g/mol)	1419.5	402.92	4963	342.43
CAS number	137525-51-0	89030-95-5	77591-33-4	67727-97-3
PubChem CID	9941957	71587328	16132341	125672
Compound class	Synthetic pentadecapeptide	Copper(II) complex of a tripeptide	Full-length thymosin beta-4, an actin-binding peptide, as the acetate salt	Tripeptide from the end of alpha-MSH
Evidence base	Mostly rodent and cell studies; one clinical study in a 2025 systematic review 3	Chemistry, cell and animal studies summarised here	Cell and animal studies; phase 1 trials in healthy volunteers 4 5	Cell and animal studies; no clinical trial found
WADA status (2026 list)	Prohibited, S0 non-approved substances 6	Not named on the list	Prohibited, S2.3 (thymosin-β4 and its derivatives, e.g. TB-500) 6	Not named on the list
TGA status	Named as an unapproved peptide product 7	Named as an unapproved peptide product 7	Named as an unapproved peptide product, as TB-500 7	Not named in the TGA advisory 7

The TB-500 in KLOW is full-length thymosin beta-4 acetate, per the supplier’s specification, and the batch certificate records it. The name TB-500 is also used in the market for a 7-residue fragment, Ac-LKKTETQ (889.0 g/mol) 1.

What is the KLOW peptide blend?

KLOW is a mixture of four peptides, BPC-157, GHK-Cu, TB-500 and KPV, supplied together as one lyophilised powder for laboratory research.

By mass, GHK-Cu makes up 50 of the 80 mg, and the other three 10 mg each. Equal masses do not mean equal numbers of molecules: the four components range from 342.43 g/mol (KPV) to 4963 g/mol (thymosin beta-4) 1, so a milligram of KPV contains about 14 times as many molecules as a milligram of thymosin beta-4.

The name KLOW does not appear in the scientific literature. A PubMed search on 28 September 2026 for “KLOW” together with “peptide” returned no records, and searches pairing GHK-Cu or KPV with BPC-157 or TB-500 returned review and analytical articles but no study of a combination.

How are the four components structured?

The four components range from 3 to 43 amino acids: two tripeptides, one carrying a bound copper ion, a 15-residue peptide and the 43-residue thymosin beta-4.

• BPC-157 is a 15-amino-acid peptide, GEPPPGKPADDAGLV. Chang et al. (2011) described it as a partial sequence of a protein called body protection compound, discovered in and isolated from human gastric juice 8.
• GHK-Cu is the copper(II) complex of the tripeptide glycyl-L-histidyl-L-lysine (GHK). Pickart et al. (1980) reported that GHK isolated from plasma came with roughly equimolar copper, and that the tripeptide readily formed complexes with copper(II) 9.
• TB-500 in KLOW is full-length thymosin beta-4 acetate. UniProt lists human thymosin beta-4 as a 43-amino-acid chain with an acetylated N-terminal serine, once its first methionine is removed 2. TB-500 vs thymosin beta-4 explains how the name is used.
• KPV is the tripeptide lysine-proline-valine. UniProt places alpha-melanocyte-stimulating hormone (alpha-MSH) at residues 138 to 150 of the precursor protein pro-opiomelanocortin, with the sequence SYSMEHFRWGKPV and an amidated C-terminal valine 2. KPV matches the last three of those residues; PubChem’s KPV record is the free acid, without the amide 1.

Illustration: four peptide chains of different lengths; not the actual structures.

What mechanisms have researchers studied for each component?

Each component has been studied through different pathways, in different models, by different groups.

BPC-157. In rat tendon fibroblasts, Chang et al. (2011) reported increased cell migration and spreading and increased phosphorylation of the signalling proteins FAK and paxillin 8. A later cell study by the same group reported that BPC-157 increased growth hormone receptor expression in rat tendon fibroblasts at the mRNA and protein levels 10.

GHK-Cu. Early work focused on copper. Pickart et al. (1980) proposed that GHK may act as a copper transport factor, and reported that it increased copper uptake into cultured hepatoma cells 9. In solution, Lau and Sarkar (1981) found that GHK competed with albumin for copper(II) 11. Later work turned to gene expression: Campbell et al. (2012) used the Connectivity Map, a database of gene-expression responses to compounds, to identify GHK as a compound whose expression profile ran opposite to a gene signature of emphysema-related lung tissue destruction 12. In mice with lipopolysaccharide-induced lung injury, Park et al. (2016) reported suppressed NF-κB p65 and p38 MAPK signalling in animals given GHK-Cu 13.

Thymosin beta-4 (TB-500). Safer et al. (1991) reported that thymosin beta-4 formed a 1:1 complex with actin monomers and inhibited actin polymerisation 14; actin is a structural protein that cells use to move and change shape. In cultured heart cells and in mice after coronary artery ligation, Bock-Marquette et al. (2004) reported that thymosin beta-4 formed a complex with PINCH and integrin-linked kinase (ILK), activated the kinase Akt, and was associated with higher early heart muscle cell survival 15.

KPV. Dalmasso et al. (2008) reported that KPV entered human intestinal epithelial cells and immune cells through PepT1, a di- and tripeptide transporter, and inhibited NF-κB and MAP kinase inflammatory signalling at nanomolar concentrations 16. Kannengiesser et al. (2008) reported effects in mice lacking a functional melanocortin-1 receptor, and concluded that they were at least partly independent of that receptor 17.

What does the published research include?

The research is component by component: cell and animal studies on each peptide, and one rat study that combined BPC-157 and TB-500. The table lists representative primary studies for each component; it is not a systematic review.

Study	Study type	Model	What was measured	Reported finding
Staresinic, 2003 (BPC-157)	Animal and cell study	Rats with a transected Achilles tendon; cultured rat tendon cells	Load to failure, functional index, histology; cell growth	Higher load to failure and functional index values than controls; no effect on cell growth alone
Vasireddi, 2025 (BPC-157)	Systematic review	36 included studies: 35 preclinical, 1 clinical	Mechanism, musculoskeletal outcomes, metabolism, safety data	Evidence rated as level IV and V; no clinical safety data found
Lau, 1981 (GHK-Cu)	Solution chemistry study	GHK, copper(II), albumin and histidine in solution	Species, stability constants, competition with albumin	About 42% of copper(II) bound to GHK at equimolar albumin and peptide
Campbell, 2012 (GHK)	Human tissue and cell study	Lung tissue from smokers with COPD; human lung fibroblasts	Gene expression; collagen gel contraction by fibroblasts	GHK identified as reversing an emphysema-associated gene signature; restored collagen I contraction by fibroblasts from COPD lungs
Park, 2016 (GHK-Cu)	Animal and cell study	Mice with lipopolysaccharide-induced lung injury; RAW 264.7 macrophages	TNF-α, IL-6, NF-κB and p38 signalling, lung histology	Lower TNF-α and IL-6, suppressed signalling, fewer inflammatory cells in lung tissue
Bock-Marquette, 2004 (thymosin beta-4)	Cell and animal study	Embryonic and postnatal heart muscle cells in culture; mice after coronary artery ligation	Cell migration and survival; ILK and Akt activity	More migration and survival in culture; higher ILK and Akt activity and early heart muscle cell survival in mice
Biçer, 2026 (BPC-157 and TB-500)	Animal study	32 rats with a repaired Achilles tendon transection, in four groups	Maximum load to failure, Bonar and Movin histology scores, collagen I and III	Higher load to failure in the BPC-157 and TB-500 groups, significant only for TB-500; no additional effect from combining them
Dalmasso, 2008 (KPV)	Cell and animal study	Human intestinal epithelial and T cell lines; mice with DSS- and TNBS-induced colitis	NF-κB and MAP kinase signalling, cytokines, PepT1 uptake	Inhibited inflammatory signalling at nanomolar concentrations via PepT1; lower colitis incidence in both models
Kannengiesser, 2008 (KPV)	Animal study	Mice with DSS colitis and transfer colitis, including melanocortin-1 receptor mutants	Body weight, colon histology, myeloperoxidase activity	Fewer inflammatory infiltrates and lower myeloperoxidase activity; effects partly independent of the receptor

The only controlled study found that combined any two KLOW components is the 2026 rat study by Biçer et al. It compared BPC-157, TB-500 and the pair against controls over four weeks after tendon repair, and the authors reported no additional effect from the combination over either peptide alone. Its abstract describes TB-500 as synthetic thymosin beta-4, without saying whether the fragment or the full protein was used 19. The BPC-157 and TB-500 blend article covers that pairing.

What are the limits of the evidence?

The evidence describes each component separately, mostly in cells and rodents, and none of it describes KLOW as a mixture.

• No studies of the four-part blend. Results from separate studies cannot be added together, and interactions between the components have not been tested. The one combination study found covered two components in one rat model 19.
• Mostly preclinical. A 2025 systematic review of BPC-157 included 35 preclinical studies and one clinical study, and found no clinical safety data 3. Full-length thymosin beta-4 has been tested in phase 1 trials in healthy volunteers, which measured tolerability and pharmacokinetics 4 5. We found no clinical trial of KPV in PubMed on 28 September 2026. Why most peptide research is preclinical and how to read a peptide study explain what cell and animal evidence can and cannot show.
• Concentration in one group. A PubMed title search for BPC-157 on 28 September 2026 returned 199 records, of which 166 list P. Sikiric as an author 20. Sikiric’s group is based in the Department of Pharmacology at the University of Zagreb, as listed on, for example, its 2018 review 21. Independent work exists, such as tendon fibroblast studies from Chang Gung University in Taiwan 8, but it is a small share.
• Which TB-500. Studies of full-length thymosin beta-4 and of the 7-residue fragment are separate literatures, and results for one cannot be assumed to apply to the other. Some studies do not say which they used 19.

What is the regulatory and anti-doping status of KLOW’s components in Australia?

Three of KLOW’s four components are named in a TGA safety advisory as examples of unapproved peptide products, and two are named on the WADA Prohibited List.

The TGA safety advisory of 13 April 2026 names BPC-157, GHK-Cu, TB-500, retatrutide and CJC-1295 as examples of unapproved peptide products, meaning goods not included in the Australian Register of Therapeutic Goods (ARTG), and states that these products have not been evaluated by the TGA for safety, quality or effectiveness 7. KPV is not named in that advisory.

The WADA Prohibited List for 2026 names BPC-157 under S0, non-approved substances, and lists “thymosin-β4 and its derivatives e.g. TB-500” under S2.3, growth factors and growth factor modulators 6. GHK-Cu and KPV are not named on the 2026 list. Check the current WADA Prohibited List and Sport Integrity Australia for the latest position. Our anti-doping status overview covers each compound.

How is a four-component blend like KLOW characterised in the lab?

A four-component blend is characterised by separating the peptides, confirming each one’s identity by mass, and measuring each one against its own reference standard.

The components span a 14-fold mass range, from 342.43 g/mol for KPV to 4963 g/mol for thymosin beta-4 1, so one method has to handle both small tripeptides and a protein-sized peptide. In electrospray mass spectrometry, large molecules give a sequence of multiply charged peaks 22, so thymosin beta-4’s mass is read from that series rather than from a single peak. Anti-doping laboratories have identified BPC-157 in confiscated vials 23 and thymosin β4 in black-market products 24 by mass spectrometry. The copper in GHK-Cu adds a further, separate measurement. How multi-component peptide blends are tested explains the full process. Batch reports are in our COA library and can be checked on the verification page.

Illustration: liquid chromatography separates each component of a blend into its own peak.

Frequently asked questions

What is in the KLOW peptide blend?

KLOW contains four peptides in one 80 mg lyophilised vial: GHK-Cu (50 mg), BPC-157 (10 mg), TB-500 (10 mg) and KPV (10 mg). PubChem lists their molecular weights as 402.92, 1419.5, 4963 and 342.43 g/mol respectively 1; the TB-500 is full-length thymosin beta-4. KLOW is a trade name and does not appear in published research. The KLOW vs BPC-157 and TB-500 comparison sets out how it differs from the two-component blend.

Has the KLOW blend itself been studied?

No published study has tested KLOW or any mixture of all four components. A PubMed search on 28 September 2026 found no records. The closest is a 2026 rat study by Biçer et al. that compared BPC-157, TB-500 and the two combined after Achilles tendon repair; the authors reported no additional effect from the combination 19. We found no study that combined GHK-Cu or KPV with BPC-157 or TB-500.

Is the TB-500 in KLOW thymosin beta-4?

Yes. The TB-500 in KLOW is full-length thymosin beta-4 acetate, the 43-amino-acid peptide listed in UniProt as P62328 2, at 4963 g/mol 1, per the supplier’s specification, and the batch certificate records it. The name TB-500 is also used in the market for a 7-residue fragment, Ac-LKKTETQ (889.0 g/mol), which Esposito et al. (2012) identified in a TB-500 formulation 25. See TB-500 vs thymosin beta-4.

Are KLOW’s components on the WADA Prohibited List?

Two of them are named on the 2026 WADA Prohibited List: BPC-157 under S0, non-approved substances, and thymosin-β4 and its derivatives, including TB-500, under S2.3, growth factors and growth factor modulators 6. GHK-Cu and KPV are not named on the 2026 list. Check the current WADA Prohibited List and our anti-doping status overview for updates.

How is each component in a blend identified?

Each component is separated by liquid chromatography and identified by mass spectrometry, then measured against its own reference standard. Anti-doping laboratories have identified BPC-157 23 and thymosin β4 24 in products by mass spectrometry. The four components’ molecular weights, from 342.43 to 4963 g/mol 1, differ widely, which makes them straightforward to tell apart by mass. How multi-component peptide blends are tested explains each step.

References

1. PubChem, National Center for Biotechnology Information. Compound summaries for BPC-157 (CID 9941957), prezatide copper, GHK-Cu (CID 71587328), thymosin beta-4, timbetasin (CID 16132341), TB-500 fragment Ac-LKKTETQ (CID 62707662), Lys-Pro-Val, KPV (CID 125672). Accessed 28 September 2026. [chemical database]
2. UniProt Consortium. UniProtKB entries P62328, thymosin beta-4, human and P01189, pro-opiomelanocortin, human. Accessed 28 September 2026. [protein database]
3. Vasireddi N, Hahamyan H, Salata MJ, et al. Emerging Use of BPC-157 in Orthopaedic Sports Medicine: A Systematic Review. HSS J. 2025;21(4):485-495. doi:10.1177/15563316251355551. PMID: 40756949. PMCID: PMC12313605. [systematic review]
4. Ruff D, Crockford D, Girardi G, et al. A randomized, placebo-controlled, single and multiple dose study of intravenous thymosin beta4 in healthy volunteers. Ann N Y Acad Sci. 2010;1194:223-229. doi:10.1111/j.1749-6632.2010.05474.x. PMID: 20536472. [phase 1 randomised, placebo-controlled trial]
5. Wang X, Liu L, Qi L, et al. A first-in-human, randomized, double-blind, single- and multiple-dose, phase I study of recombinant human thymosin β4 in healthy Chinese volunteers. J Cell Mol Med. 2021;25(17):8222-8228. doi:10.1111/jcmm.16693. PMID: 34346165. PMCID: PMC8419156. [phase 1 randomised, double-blind trial]
6. World Anti-Doping Agency. World Anti-Doping Code International Standard: Prohibited List 2026, in effect from 1 January 2026. https://www.wada-ama.org/en/prohibited-list. Accessed 28 September 2026. [anti-doping standard]
7. Therapeutic Goods Administration. Understanding your responsibilities when importing, compounding and supplying unapproved peptide products. Safety advisory, 13 April 2026. https://www.tga.gov.au/safety/safety-monitoring-and-information/safety-alerts/understanding-your-responsibilities-when-importing-compounding-and-supplying-unapproved-peptide-products. Accessed 28 September 2026. [regulator advisory]
8. Chang CH, Tsai WC, Lin MS, et al. The promoting effect of pentadecapeptide BPC 157 on tendon healing involves tendon outgrowth, cell survival, and cell migration. J Appl Physiol (1985). 2011;110(3):774-780. doi:10.1152/japplphysiol.00945.2010. PMID: 21030672. [rat tendon explant and cell study]
9. 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. PMID: 7453802. [chemistry and cell study]
10. Chang CH, Tsai WC, Hsu YH, et al. Pentadecapeptide BPC 157 enhances the growth hormone receptor expression in tendon fibroblasts. Molecules. 2014;19(11):19066-19077. doi:10.3390/molecules191119066. PMID: 25415472. PMCID: PMC6271067. [rat cell study]
11. Lau SJ, Sarkar B. The interaction of copper(II) and glycyl-L-histidyl-L-lysine, a growth-modulating tripeptide from plasma. Biochem J. 1981;199(3):649-656. doi:10.1042/bj1990649. PMID: 7340824. PMCID: PMC1163421. [solution chemistry study]
12. Campbell JD, McDonough JE, Zeskind JE, et al. A gene expression signature of emphysema-related lung destruction and its reversal by the tripeptide GHK. Genome Med. 2012;4(8):67. doi:10.1186/gm367. PMID: 22937864. PMCID: PMC4064320. [human tissue gene-expression and cell study]
13. Park JR, Lee H, Kim SI, et al. The tri-peptide GHK-Cu complex ameliorates lipopolysaccharide-induced acute lung injury in mice. Oncotarget. 2016;7(36):58405-58417. doi:10.18632/oncotarget.11168. PMID: 27517151. PMCID: PMC5295439. [mouse and cell study]
14. Safer D, Elzinga M, Nachmias VT. Thymosin beta 4 and Fx, an actin-sequestering peptide, are indistinguishable. J Biol Chem. 1991;266(7):4029-4032. doi:10.1016/s0021-9258(20)64278-8. PMID: 1999398. [biochemistry study]
15. Bock-Marquette I, Saxena A, White MD, et al. Thymosin beta4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair. Nature. 2004;432(7016):466-472. doi:10.1038/nature03000. PMID: 15565145. [cell and mouse study]
16. Dalmasso G, Charrier-Hisamuddin L, Nguyen HT, et al. PepT1-mediated tripeptide KPV uptake reduces intestinal inflammation. Gastroenterology. 2008;134(1):166-178. doi:10.1053/j.gastro.2007.10.026. PMID: 18061177. PMCID: PMC2431115. [cell and mouse study]
17. Kannengiesser K, Maaser C, Heidemann J, et al. Melanocortin-derived tripeptide KPV has anti-inflammatory potential in murine models of inflammatory bowel disease. Inflamm Bowel Dis. 2008;14(3):324-331. doi:10.1002/ibd.20334. PMID: 18092346. [mouse study]
18. Staresinic M, Sebecic B, Patrlj L, et al. Gastric pentadecapeptide BPC 157 accelerates healing of transected rat Achilles tendon and in vitro stimulates tendocytes growth. J Orthop Res. 2003;21(6):976-983. doi:10.1016/s0736-0266(03)00110-4. PMID: 14554208. [rat study with cultured tendon cells]
19. Biçer O, Adanir O, Güleryüz Y, et al. Effects of BPC-157 and TB-500 on Achilles tendon healing in rats: A histopathological and biomechanical study. Jt Dis Relat Surg. 2026;37(3):822-837. doi:10.52312/jdrs.2026.2951. PMID: 42542926. [rat study]
20. National Library of Medicine. PubMed title search for BPC-157 (“BPC 157”[ti] OR “BPC-157”[ti] OR “BPC157”[ti]), alone and combined with Sikiric P[au]. https://pubmed.ncbi.nlm.nih.gov/. Searched 28 September 2026. [database search]
21. Seiwerth S, Rucman R, Turkovic B, et al. BPC 157 and Standard Angiogenic Growth Factors. Gastrointestinal Tract Healing, Lessons from Tendon, Ligament, Muscle and Bone Healing. Curr Pharm Des. 2018;24(18):1972-1989. doi:10.2174/1381612824666180712110447. PMID: 29998800. [narrative review]
22. Fenn JB, Mann M, Meng CK, et al. Electrospray ionization for mass spectrometry of large biomolecules. Science. 1989;246(4926):64-71. doi:10.1126/science.2675315. PMID: 2675315. [methods review]
23. Cox HD, Miller GD, Eichner D. Detection and in vitro metabolism of the confiscated peptides BPC 157 and MGF R23H. Drug Test Anal. 2017;9(10):1490-1498. doi:10.1002/dta.2152. PMID: 28035768. [analytical method validation study]
24. Krug O, Thomas A, Walpurgis K, et al. Identification of black market products and potential doping agents in Germany 2010-2013. Eur J Clin Pharmacol. 2014;70(11):1303-1311. doi:10.1007/s00228-014-1743-5. PMID: 25168622. [analytical study of confiscated products]
25. Esposito S, Esposito S, Deventer K, 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. PMID: 22962027. [analytical chemistry study]