F tier · safety concern
There are zero registered trials and zero published studies - human, animal or in vitro - of these four peptides administered together, and no monograph or standards body defines what KLOW contains. The components are graded B, D, D and D individually in this index, but the blend as a blend has effectively no rigorous evidence at all.
klow
KLOW is a vendor-assembled blend of four peptides - GHK-Cu, BPC-157, TB-500 and KPV - supplied in a single vial, with the name functioning as an acronym of the components. Most listings converge on the same nominal 5:1:1:1 mass ratio, but no pharmacopoeia, monograph or reference standard defines the product, and at least one seller treats the formula as proprietary. Nothing has been published on the four given in combination.
// we supply this one
available as a research reagent
each component ≥ 98% HPLC · all four reported on the batch COA · lyophilised powder · batch certificate published. Grade F above is our own and is not adjusted because we stock it.
the explanation
KLOW is four different research peptides mixed together and sold in one bottle. There is no official recipe for it, so the label is only a promise from whoever made it, and nobody has ever run a study on the mixture itself. Everything said about it is copied across from separate research on the four ingredients.
regulatory status
unapproved everywhere; no monograph, no defined standard
No blend of these four peptides holds a marketing authorisation in the UK, the EU or the US, and there is no pharmacopoeial monograph or reference standard for KLOW or for any of its four components, so no regulator or standards body defines what the name means. All four were nominated for the FDA 503A compounding bulks list and all four nominations were withdrawn; FDA's Pharmacy Compounding Advisory Committee then voted 8-6 on 23 July 2026 to recommend BPC-157 and KPV for that list and also backed TB-500, over the objection of FDA staff who argued BPC-157 is not well characterised and that quality standards cannot be established for it. Those votes are advisory only, concern individual bulk substances for patient-specific compounding, and would not legitimise a fixed four-peptide blend. In sport the blend is prohibited regardless of its other contents, because BPC-157 is banned at all times under WADA class S0 and thymosin-beta-4 derivatives including TB-500 under S2.3; GHK-Cu is separately lawful in cosmetics as copper tripeptide-1, but that permission does not extend to an injectable multi-peptide preparation, and none of the four is a lawful dietary-supplement ingredient in the UK, EU or US.
how it works · proposed mechanism
KLOW has no mechanism of its own. It has four, running in parallel, each described from separate single-molecule work and none of them characterised in the presence of the other three. The blend is therefore a hypothesis about additivity rather than a pharmacological entity.
Four unrelated pathways in one vial
GHK-Cu acts as a copper shuttle feeding copper-dependent matrix enzymes; BPC-157 is proposed to act on angiogenic and nitric-oxide signalling in rodent injury models; TB-500 reproduces the actin-binding motif of thymosin beta-4; KPV enters cells via the PepT1 transporter and suppresses NF-kB signalling. These are four separate literatures with no common node. Nothing links them into a single pathway that the blend could be said to target.
Copper dominates the mass
In the commonly listed 5:1:1:1 ratio the copper tripeptide is roughly five-eighths of the peptide mass, so KLOW is mostly a GHK-Cu product with three minor additions. That matters because GHK-Cu is the only component with randomised human wound trials, and it is also the component that introduces a redox-active metal into the mixture.
Synergy is assumed, not measured
Combining four agents can be additive, sub-additive or antagonistic, and which it is can only be determined experimentally. No study has compared the blend against its individual components, in any species or in cell culture. The claim that the four 'work together' is a marketing premise with no supporting experiment.
Co-formulation chemistry is uncharacterised
A copper(II) complex sharing a container with three other peptides raises ordinary formulation questions - whether the copper stays bound to its tripeptide, whether it catalyses degradation, whether the components remain independently stable across reconstitution and storage. A PubMed search for GHK-Cu together with stability, compatibility or co-formulation returns work on polymers and delivery vehicles only, with nothing on multi-peptide vials. No data answer these questions for KLOW.
what’s reported
evidence shape
7 sourcesThe composition of the cited literature by study type. This describes the shape of the evidence, not its quality — and it does not by itself set the grade.
⚠ the catch
KLOW is a marketing acronym, not a defined substance: no monograph, no reference standard and no body sets its composition, so the contents of a vial are whatever the seller decided to put there. Seven vendor listings checked converge on a 5:1:1:1 mass ratio, but one describes its formula as proprietary and declines to publish the split, and another states a total peptide content in its specification table 12.5% below the figure in its own product title. A third-party certificate published on one vendor's own page reports measured content about 18% above the declared total, with individual components between roughly 15% and 29% over label, so even a tested batch does not deliver the ratio printed on it. Against that, there are zero registered trials and zero published studies of these four peptides given together, in humans, animals or cell culture. Every benefit attributed to KLOW is transposed from single-molecule work on components this index grades B, D, D and D.
key published findings
- Seven vendor listings checked state the same nominal composition - GHK-Cu, BPC-157, TB-500 and KPV in a 5:1:1:1 mass ratio - but no pharmacopoeia, monograph or standards body defines it, so that ratio is a market convention rather than a specification.
- ClinicalTrials.gov returns no registered study of the blend: a term search for KLOW returns a single unrelated cystic-fibrosis education study, a search for GHK-Cu returns two single-agent studies, and a search for KPV returns none. The EU Clinical Trials Register returns zero results for KLOW, for GHK-Cu and for BPC-157.
- PubMed returns zero records for GHK-Cu combined with KPV and zero for TB-500 combined with KPV. No indexed paper even mentions all four peptides together, let alone administers them together.
- The five PubMed records returned for BPC-157 combined with GHK-Cu are all 2026 narrative or systematic reviews of peptides generally, not studies of the combination.
- One vendor publishes a third-party certificate of analysis dated 8 June 2026 whose measured content exceeds the declared total by about 18%, with per-component overages between roughly 15% and 29%; the copper tripeptide's measured share of the vial falls from a nominal 62.5% to about 61%.
- Two of the four components are on the WADA Prohibited List: BPC-157 under S0 since the 2022 list, and thymosin-beta-4 derivatives including TB-500 under S2.3 since the 2018 list.
limitations of the evidence
- No pharmacokinetic, stability or compatibility data exist for the four peptides co-formulated in one container; whether the copper(II) complex remains intact or redistributes copper to the other components in solution has never been studied.
- Synergy is asserted by every seller and demonstrated by none - no experiment in any species has compared the blend against its individual components.
- Composition is set by the seller, not by a standard. At least one vendor calls the formula proprietary and does not publish the split, and another contradicts its own product title in its specification table, so two vials labelled KLOW need not contain the same thing.
- All efficacy claims are borrowed from single molecules: wound-healing claims from small GHK-Cu trials of 1992 and 1994, tendon and gut claims from a largely single-group BPC-157 rodent literature, actin and repair claims from full-length thymosin beta-4 rather than the TB-500 fragment, and anti-inflammatory claims from KPV cell and mouse colitis models.
- Because no combination study exists, the safety of four simultaneous unapproved peptides - one of them a metal complex - cannot be inferred by adding up the individual components' records.
- The July 2026 FDA advisory committee votes concern individual bulk substances for patient-specific compounding; they are not approvals, they were opposed by FDA staff, and they say nothing about a fixed four-peptide blend.
documented safety signals
- No adverse-event dataset exists for the blend because no study of the blend exists; the absence of reported harm here reflects the absence of any investigation, not evidence of safety.
- FDA scientists told the July 2026 Pharmacy Compounding Advisory Committee that BPC-157 is not well characterised and that quality standards cannot be established for it, and argued against adding it to the 503A bulks list; those concerns travel into any product containing it.
- FDA's stated concerns for this peptide class centre on immunogenicity arising from peptide-related impurities and aggregates. A four-component mixture multiplies the number of uncharacterised impurity and degradation sources in one container, and no impurity profile has been published for the blend as a blend.
- One vendor's own certificate shows components present at up to roughly 29% above label, indicating loose content control on this product class in both directions.
- Two components are WADA-prohibited, so a tested athlete faces a sanction from this product regardless of intent or of which component was responsible.
identity
| full name | Fixed-ratio four-peptide blend of GHK-Cu, BPC-157, TB-500 and KPV sold under the acronym KLOW |
| category | Healing & Repair |
| modality | peptide |
laboratory handling
| storage | Lyophilised powder is stored desiccated at -20 °C and protected from light. Once reconstituted, laboratory practice is refrigeration at 2-8 °C for short-term use, or aliquoting and freezing to avoid repeated freeze-thaw cycles. No published stability or compatibility data exists for these four peptides co-formulated in one vial, so handling guidance here is inferred from the components rather than measured on the blend. |
| solubility | The components are individually soluble in sterile or bacteriostatic water. Behaviour of the mixture — including whether the copper tripeptide interacts with the other three on reconstitution — has not been studied and is not characterised. |
| co-studied with | KLOW is itself a pre-made stack rather than a compound, and a three-component version omitting KPV is sold under the name GLOW. Because the ratio is fixed by the seller the components cannot be varied independently, and two of the four are prohibited in sport. |
Handling information describes laboratory practice for a research reagent. It is not a preparation guide for use in humans.
the receipts
7 citedU.S. Food and Drug Administration · 2026 · official
U.S. Food and Drug Administration · 2026 · official
U.S. Anti-Doping Agency · 2021 · official
U.S. Anti-Doping Agency · 2017 · official
Sports Medicine · 2026 · review
Verified Peptides (vendor listing) · 2026 · observational
Peptides Source (vendor listing) · 2026 · observational
others in Healing & Repair