# Compare BPC-157, TB-500, GHK-Cu and KLOW — Agility Peptide

> A side-by-side comparison of four Recovery & Tissue Repair research peptides — BPC-157, TB-500, GHK-Cu and KLOW — across peptide class, evidence base, administration studied, regulatory status and key caution.

Where the four repair compounds converge, where they diverge, and — most importantly — how far the evidence behind each one actually reaches.

## The short version

This page lines up [BPC-157](/bpc-157), [TB-500](/tb-500), [GHK-Cu](/ghk-cu) and [KLOW](/klow) on the dimensions that matter most for reading research peptides: what kind of molecule each one is, where it has been studied, how strong that evidence is, how it was administered in studies, its regulatory standing, and its defining caution. The headline: all four are positioned around recovery and tissue repair, but at very different evidence levels. GHK-Cu has the most human (mostly topical) data. BPC-157 has the deepest animal record with three tiny human pilots. TB-500's strongest evidence belongs to a larger parent protein. KLOW has per-component literature but zero controlled blend data. None is an approved medicine; none is presented here with a human dose.

## The comparison matrix

| Dimension | BPC-157 | TB-500 | GHK-Cu | KLOW |
| --- | --- | --- | --- | --- |
| Peptide class | Stable gastric pentadecapeptide (15 aa) | Synthetic actin-binding fragment of thymosin beta-4 (7 aa) | Copper-binding tripeptide / copper tripeptide-1 (3 aa) | Co-formulated blend: KPV (3 aa) + GHK-Cu (3 aa) + BPC-157 (15 aa) + TB-500 (7 aa) |
| Most-studied in | Tendon, gut, muscle and nerve repair | Actin biology; cell migration and angiogenesis | Skin regeneration and matrix synthesis | No blend study; per-component: gut inflammation (KPV), skin/matrix (GHK-Cu), tendon/gut (BPC-157), actin/migration (TB-500/Tβ4) |
| Evidence base (model) | Mostly rat; 3 small human pilots [2] | Mostly full-length Tβ4 (animal + 1 human Phase 1) [8][11] | In vitro + small human topical trials [16] | No blend data; component-level only; see individual pages |
| Administration studied | IM, intragastric, drinking water, IV pilot [3][5] | IV (full-length Tβ4), IP in animals [9][11] | Topical, ex vivo skin penetration [13][17] | No blend study; component routes only |
| Regulatory / WADA status | Not approved; WADA S0 prohibited | Not approved; WADA-prohibited | Cosmetic ingredient (topical); systemic unapproved | Not approved; contains TB-500 → WADA-prohibited blend |
| Key caution | Single-lab, preclinical-heavy record [2] | Fragment vs. full-protein identity gap [8] | Poor skin permeability; pigmentation risk [13] | No controlled blend trial; pharmacokinetic mismatch across four components [8][3] |

## Peptide class

The four span a structural range. BPC-157 is the largest standalone peptide at fifteen amino acids, a stable gastric pentadecapeptide. TB-500 is a seven-amino-acid fragment of thymosin beta-4. GHK-Cu is a three-amino-acid copper chelate derived from collagen. KLOW is not a single peptide at all but a co-formulated blend combining all three size categories: three-amino-acid tripeptides (KPV and GHK-Cu), the fifteen-amino-acid BPC-157, and the seven-amino-acid TB-500 fragment.

## Most-studied in

Each entry has a research home. BPC-157's animal record spans tendon, gut, muscle and nerve [5][6]. TB-500's research centers on actin biology and the cell migration and angiogenesis that follow [10]. GHK-Cu is overwhelmingly a skin-and-matrix story — collagen, elastin and the dermal environment [16]. KLOW has no home territory of its own because it has never been studied as a blend; it borrows the research territories of its four components.

## Evidence base (model)

This is where the four genuinely separate. GHK-Cu has the most human data: mostly topical and small-scale, plus one 45-patient combination hair-loss RCT [15][16]. BPC-157 has a deep animal record and three small uncontrolled human pilots [2]. TB-500 is the trickiest: the strongest human data — a Phase 1 IV safety study in 40 volunteers — used full-length Tβ4, not the marketed fragment [8][11]. KLOW has no blend-level evidence at all; any discussion of its combined effects is mechanistic extrapolation from single-component preclinical studies.

## Administration studied

Routes reflect the research questions. BPC-157 has been studied intramuscularly, intragastrically, in drinking water, and in a tiny intravenous human safety pilot [3][5]. TB-500 / Tβ4 used intravenous dosing in the human Phase 1 study and intraperitoneal dosing in animals [9][11]. GHK-Cu is studied topically, with ex vivo skin penetration measuring copper transport across the dermis [13][17]. KLOW has no studied administration route as a blend — routes reported in community use are anecdotal, not experimental [8].

## Regulatory / WADA status

None of the four is an FDA- or EMA-approved medicine for systemic use. BPC-157 and TB-500 are both explicitly prohibited in sport (BPC-157 under WADA S0 non-approved substances; TB-500/Tβ4 under S2 peptide hormones/growth factors) [2][8]. GHK-Cu is unusual: topical copper tripeptide-1 is a legal, widely sold cosmetic ingredient, while injectable or systemic GHK-Cu is unapproved research-only [13]. KLOW, because it contains TB-500, implicates the WADA prohibition regardless of the dosing route or intent — the blend as a whole is off-limits in any anti-doping-regulated sport context.

## Key caution

Each entry carries a defining caveat. For BPC-157 it is that the broad signal lives almost entirely in one laboratory's rodents, with only three tiny human pilots [2]. For TB-500 it is the identity gap: the marketed fragment is not the molecule behind most of the efficacy data, and the parent protein has a theoretical tumor-angiogenesis signal [8][10]. For GHK-Cu it is poor skin permeability and a documented risk of localized hyperpigmentation [13]. For KLOW it is the complete absence of any controlled blend study, combined with an inherent pharmacokinetic mismatch across four components whose individual half-lives differ substantially [8][3]. The lesson across all four is consistent: mechanistically interesting, evidentiary footing uneven and often early.

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Peer-reviewed data, plain-English summaries — a research digest, not a dose guide and not a product for sale.