# Inside the KLOW Peptide Stack: The Four Peptides — klow stack Component Breakdown > Inside the KLOW stack: a component-by-component breakdown of KPV, GHK-Cu, BPC-157 and TB-500 — molecular weight, role, vial share, and how the klow stack compares to GLOW. Molecular identifiers, vial-share ratios, research roles and pharmacokinetic properties for KPV, GHK-Cu, BPC-157 and TB-500 — the four distinct compounds that make up the klow stack, dimensioned as separate components. ## In plain English Inside the KLOW stack, there are four separate compounds — not one molecule — co-dissolved in the same research vial. Understanding the klow stack means understanding each part individually, because that is the only level at which published research exists. The typical vial contains 80 mg total: mostly GHK-Cu (50 mg, a copper-chelated tripeptide), then equal 10 mg shares of BPC-157 (a 15-amino-acid gastric peptide), TB-500 (a heptapeptide derived from thymosin beta-4), and KPV (a tripeptide from alpha-MSH). The four have different molecular weights, different clearance rates, and different research track records. None is FDA-approved. The blend has never been tested as a combination. This page sets out each component as a separate dimensioned part. ## klow blend The KLOW blend composition (canonical 80 mg research vial): GHK-Cu 50 mg (CAS 89030-95-5, MW 402.92 Da — the copper-chelated tripeptide glycyl-L-histidyl-L-lysine); BPC-157 10 mg (CAS 137525-51-0, MW 1419.53 Da — the 15-amino-acid gastric peptide GEPPPGKPADDAGLV); TB-500 10 mg (MW 889.02 Da — the N-acetylated heptapeptide Ac-LKKTETQ, actin-binding region of thymosin beta-4); KPV 10 mg (CAS 67727-97-3, MW 342.44 Da — the tripeptide Lys-Pro-Val, residues 11-13 of alpha-MSH). GHK-Cu is the mass-dominant component at 62.5% by mass — a design choice with implications for the copper load and the collagen-synthesis arm of the formulation. The three 10 mg components are present at equal mass but differ enormously in molecular weight: KPV at 342.44 Da is the smallest molecule in the vial; BPC-157 at 1419.53 Da is the largest. At equal mass, the molar quantity of KPV dosed is approximately four times that of BPC-157. ## KPV — anti-inflammatory arm **Part: KPV · CAS 67727-97-3 · MW 342.44 Da · Vial share: 10 mg** KPV (Lys-Pro-Val) is the C-terminal three-residue segment of alpha-MSH (alpha-melanocyte-stimulating hormone). Its defining research property is substrate recognition by PepT1 (SLC15A1) — the di/tripeptide transporter upregulated in inflamed intestinal epithelium — providing tissue-selective uptake into the cells most in need of anti-inflammatory signaling. Mechanistically: inhibits NF-kappaB nuclear import, suppresses MAPK ERK/p38, and reduces TNF-alpha, IL-6, IL-1beta and IL-8 at nanomolar concentrations [3]. In the 2008 Dalmasso et al. study, PepT1-mediated KPV uptake reduced intestinal inflammation in human cell lines (Caco2-BBE, HT29, Jurkat T cells) and in DSS/TNBS mouse colitis models [3]. No human approval; KPV human evidence is restricted to delivery mechanism studies. ## GHK-Cu — matrix-synthesis and angiogenesis arm **Part: GHK-Cu · CAS 89030-95-5 · MW 402.92 Da · Vial share: 50 mg** GHK-Cu (Copper Tripeptide-1) is a naturally occurring tripeptide Gly-His-Lys chelated 1:1 to copper(II). It is the mass-dominant component and the most extensively studied KLOW constituent in humans. Topical GHK-Cu formulations have placebo-controlled clinical skin data; the 2015 Pickart review documents multi-modal matrix synthesis with measured improvements in skin laxity, fine lines and wrinkle density [4]. At 1–10 nM in vitro it modulates approximately 31.2% of human protein-coding genes at a 50%-or-greater change threshold [5]. On the angiogenesis axis: SPARC proteolysis yields GHK and KGHK angiogenic peptides via a sequence-specific route [11]; liposomal GHK-Cu increases HUVEC proliferation 33.1% and upregulates VEGF and FGF-2 [10]. Supplies copper for lysyl oxidase, the crosslinking enzyme for collagen and elastin. Decades of topical cosmetic data; no approved systemic indication. ## BPC-157 — angiogenic arm **Part: BPC-157 · CAS 137525-51-0 · MW 1419.53 Da · Vial share: 10 mg** BPC-157 (Body Protection Compound 157, sequence GEPPPGKPADDAGLV) is derived from a gastric-juice protein sequence. Its angiogenesis mechanism — VEGFR2 upregulation and internalization with downstream PI3K/Akt/eNOS activation — is the most mechanistically characterized angiogenic pathway among the four components [8]. In a transected-Achilles rat study at 10 microg/10 ng/10 pg doses by intraperitoneal injection, BPC-157 accelerated tendon healing across all measured endpoints [2]. A 2025 IV safety pilot in two humans found 10–20 mg IV well tolerated with no adverse events [6]; human n=2 is not efficacy data. BPC-157 modulates angiogenesis directly during muscle and tendon healing in rats [12]. Not FDA-approved; category 2 in the 503A bulk-substances review. Short rodent elimination half-life — under approximately 30 minutes. ## TB-500 — cytoskeletal arm **Part: TB-500 · MW 889.02 Da · Vial share: 10 mg** TB-500 (Ac-LKKTETQ) is a synthetic N-acetylated heptapeptide corresponding to the actin-binding region of native thymosin beta-4 (the 43-amino-acid full protein). Most efficacy data derive from the full-length protein, not the fragment — results for native Tbeta4 should not be automatically attributed to the TB-500 heptapeptide. For the TB-500/Tbeta4 arm: in the 1999 Malinda et al. rat wound model, Tbeta4 produced +42% / +61% re-epithelialization at 4 / 7 days, wound contraction of at least 11% by day 7, and raised angiogenesis [1]. Thymosin beta-4 promotes angiogenesis, wound healing and hair-follicle development concurrently in rodents [9]. TB-500 is classified as WADA S2 — prohibited at all times in sport. Full-length thymosin beta-4 has early-phase human trial data; the heptapeptide fragment's human evidence is more limited. ## KLOW vs glow The defining structural difference between KLOW and GLOW is the inclusion of KPV. GLOW contains GHK-Cu, BPC-157 and TB-500 but NOT KPV. KLOW adds KPV as the fourth component. KPV is the C-terminal tripeptide of alpha-MSH, transported into inflamed gut and immune cells via PepT1 at Km ~160 microM [3]. Community reports comparing the two blends consistently attribute a broader anti-inflammatory quality to KLOW over GLOW, consistent with the addition of the NF-kappaB-suppressing KPV arm. Scientifically, neither blend has been tested as a combination; the attributed difference is mechanistic extrapolation from KPV's single-component anti-inflammatory literature. KLOW is not the same as WOLVERINE, which has a different composition entirely. Neither KLOW nor GLOW contains any GLP-1 agonist or incretin component; neither is a weight-management formulation. --- A technical schematic of four separate peer-reviewed literatures — each component dimensioned to its own studies, the untested combination held as the honest blank dimension.