KLOW

What KLOW is

KLOW is a convenience product: four separate peptides — KPV, GHK-Cu, BPC-157 and TB-500 — co-lyophilised into one vial at a fixed ratio of 50 : 50 : 10 : 10 mg. It is a physical mixture. Nothing in the vial is a new molecule, no chemistry has occurred between the components, and the blend is not a compound in its own right. The name is a portmanteau of KPV and GLOW; it is a marketing label, not a chemical designation.

No study has ever tested this combination

The ratio in this vial reflects the doses at which the four components are conventionally sold as singles. It is not the output of any experiment, because no experiment has been run.

Component specifications

A blend is a mixture, not a compound. The blend itself has no CAS number, no molecular formula, no molecular weight and no PubChem CID — those identifiers describe single chemical substances, and printing one for a four-component mixture would be a fabrication. We print N/A above and give the real identifiers for each component below, from PubChem.

The WADA lines above are data, reproduced from the 2026 Prohibited List^[13]. See the anti-doping section for what they mean.

Where the evidence stands

Component 1 — KPV in vitro murine

KPV is a tripeptide — lysine-proline-valine — corresponding to residues 11 to 13 of alpha-melanocyte-stimulating hormone. In a 2008 study in Gastroenterology, at nanomolar concentrations KPV inhibited activation of the NF-κB and MAP kinase signalling pathways in human intestinal epithelial cell lines and a human T-cell line, and reduced pro-inflammatory cytokine secretion. Oral KPV in drinking water was associated with reduced incidence of colitis in two chemically distinct murine models, DSS and TNBS^[1]. Two independent models is genuinely better preclinical design than most compounds in this category can claim.

The key negative finding — and the mechanistic catch

KPV is preclinical only. There is no published human clinical study of KPV of any kind — no randomised trial, no pilot, no open-label series, no pharmacokinetic study^[1]. And the mechanism itself narrows the claim rather than widening it: the same study showed KPV enters cells via PepT1, a di- and tripeptide transporter of the intestine that is induced in the inflamed colon^[1]. A PepT1-dependent mechanism is a gut-specific mechanism. It has a great deal to say about delivery to intestinal tissue and rather little to say about anything systemic. Claims that reach beyond the gut are not supported by the mechanism those same claims cite as support.

The delivery problem is real enough that researchers built around it: a 2017 study loaded KPV into hyaluronic-acid-functionalised nanoparticles inside a chitosan/alginate hydrogel specifically so the payload would survive transit and release in the colonic lumen^[2]. That engineering effort is itself evidence that naive administration of the raw peptide is not a solved problem.

Component 2 — GHK-Cu human

GHK-Cu is the copper(II) complex of glycyl-L-histidyl-L-lysine, copper tripeptide-1 in cosmetic nomenclature^[3]. It is the only component of KLOW that has been through a randomised controlled trial in humans.

The key negative finding — the 1992 RCT

Bishop et al., Journal of Vascular Surgery 1992;16(2):251–57: a prospective, randomised, evaluator-blinded trial in chronic venous stasis ulcers, three arms — silver sulfadiazine 1% cream, tripeptide copper complex 0.4% cream, and an inert vehicle placebo — with 86 evaluable patients. Silver sulfadiazine “proved to statistically reduce the ulcer size compared with a biologically active tripeptide copper complex 0.4% cream formulation or the placebo. There was no difference between the latter two treatments.“^[4]

The copper tripeptide arm was no better than inert vehicle, and was outperformed by silver sulfadiazine. This is the best human evidence that exists for GHK-Cu, and it is negative.

And a conflict of interest you should know about

The enthusiastic review literature on GHK — the papers claiming regulation of thousands of human genes — is authored from Skin Biology, Research & Development Department, Bellevue, WA^[5], a company that sells copper-peptide products. The affiliation is stated in the papers. We flag it because a reader who does not know it will overweight that literature.

Component 3 — BPC-157 rodent

A synthetic pentadecapeptide corresponding to a partial sequence of a protein isolated from human gastric juice^[6]. It carries the largest preclinical literature in this vial — transected rat Achilles tendon models^[6], fibroblast migration and FAK–paxillin phosphorylation in culture^[7] — with a 2019 review finding consistently positive soft-tissue results while noting the work is overwhelmingly in small rodent models and efficacy in humans is yet to be confirmed^[8].

The key negative finding

A 2025 narrative review in Current Reviews in Musculoskeletal Medicine found human data are extremely limited — three pilot studies in total (intraarticular knee pain, interstitial cystitis, and an intravenous safety/pharmacokinetics assessment), and concluded that until well-designed clinical trials are conducted BPC-157 should be considered investigational^[9]. No large randomised controlled trial exists. A large fraction of the positive findings originate from a single research group, so the evidence base has had far less independent replication than its volume suggests^[8].

Component 4 — TB-500 in vitro rodent

The vial contains Ac-LKKTETQ, a seven-residue fragment — not the 43-amino-acid thymosin β4 that the literature studied. High-resolution mass spectrometry of commercial TB-500 preparations identified the active ingredient as the N-acetylated 17–23 fragment of Tβ4^[10]. The regeneration literature people cite is about the 43-residue protein; the product is a 7-residue fragment, and the two are routinely conflated in a direction that flatters the fragment.

There are zero human studies of TB-500. None of any design. The only human-relevant work is a doping-control detection method^[10].

The key negative finding — the oncology signal

Tβ4 overexpression in SW480 human colon carcinoma cells markedly increased invasiveness with increased MMP-7 levels and activity; in matched patient samples, Tβ4, β-catenin, c-Myc and MMP-7 were all higher in metastatic liver lesions than in the primary colorectal tumours they came from^[11]. Overexpression also drove epithelial-mesenchymal transition — E-cadherin loss, cytosolic β-catenin — via integrin-linked kinase^[12]. And the loss-of-function experiment agrees: knocking down Tβ4 in B16F10 murine melanoma cells significantly reduced lung metastasis^[13a].

These are studies of endogenous Tβ4 inside tumour cells rather than of administered TB-500 in a healthy organism — a real distinction we are not going to erase. But the implicated mechanism is the same one invoked to explain repair, and nobody has run the study that would resolve it.

TB-500 is prohibited by WADA by name under S2.3, at all times^[13].

The fixed-ratio problem

With four components this limitation is worse, not better.

• Attribution is impossible. Any effect observed in a four-peptide preparation cannot be assigned to any one peptide, to a pair, to a higher-order interaction, or to the vehicle. There are eleven possible non-trivial subsets and this product tests exactly one of them — all four at once.
• Doses cannot be varied independently. The ratio is locked at 50 : 50 : 10 : 10. Changing the KPV means changing everything. No dose–response curve for any component is obtainable.
• There is no comparator. Without single-component and drop-out arms, nothing can be tested against anything.

A researcher who wants interpretable data buys the singles and controls the ratio. A blend is a convenience format. That is what it is for, and we will not dress it up as anything else.

Regulatory and anti-doping status

Reproduced from the WADA 2026 Prohibited List^[13], effective 1 January 2026:

• KPV — not listed by name. Captured by S0, Non-Approved Substances. Specified Substance.
• GHK-Cu — not listed by name. Captured by S0. Specified Substance. Cosmetic ingredient status is not therapeutic approval.
• BPC-157 — named explicitly in S0. Prohibited at all times. Specified Substance.
• TB-500 — named explicitly in S2.3 (“Thymosin-β4 and its derivatives e.g. TB-500”). Prohibited at all times. non-Specified Substance.

Every component of KLOW is prohibited for a tested athlete: two by name, two by the residual S0 clause. WADA’s List changes annually and individual federations may differ from it. The only authoritative source is the athlete’s own federation’s current prohibited list — not this page, and not any vendor’s. See our anti-doping reference table.

No component of KLOW has been approved for human therapeutic use by the FDA or by any other governmental regulatory health authority.

What we don’t know

• Whether these four peptides interact at all. Nobody has looked.
• Whether co-administration alters the pharmacokinetics of any of them. Uncharacterised.
• Whether the ratio in this vial is good, bad or arbitrary. No experiment has compared it to any other.
• Whether KPV does anything at all outside the gastrointestinal tract, given a PepT1-dependent mechanism.
• Whether the oncology signal associated with full-length Tβ4 transfers to the Ac-LKKTETQ fragment.
• Long-term safety of the combination in any species — entirely uncharacterised.
• Per-kilogram dosing in animal models does not scale to humans, and nothing on this page should be read as implying that it does.