- Four peptides dominate tissue-repair research: BPC-157 (tendon, ligament, gut, blood vessels), TB-500 / thymosin beta-4 (cell migration, wound closure), GHK-Cu (collagen, skin, gene expression) and KPV (inflammation).
- Each covers a different step of healing: blood supply, cell migration, matrix building and control of inflammation.
- Evidence is strongest for thymosin beta-4 (phase 2 ulcer trials) and topical GHK-Cu (small cosmetic trials); BPC-157 and KPV rest almost entirely on animal and cell studies.
- GLOW combines BPC-157, TB-500 and GHK-Cu; KLOW adds KPV. The blends are built on component data and have not been tested as combinations in published studies.
- None of these peptides is an approved medicine for tissue repair, and BPC-157 and TB-500 are prohibited in sport by WADA.
What are healing peptides?
"Healing peptides" is an informal name for short amino-acid chains that are researched for their effects on tissue repair: tendons and ligaments, skin wounds, the gut lining and the inflammation that surrounds injury. Most are fragments of larger natural proteins, which keeps them small, easy to synthesise and precise in what they signal. They are research compounds, not approved treatments, and nearly all of the positive findings come from cell cultures and animal models.
Repair is a sequence. First inflammation clears debris, then new blood vessels grow in, cells migrate into the gap, and finally collagen and other matrix are laid down and remodelled. The peptides in this guide are interesting precisely because each one maps onto a different part of that sequence.
BPC-157: tendon, ligament and gut repair
BPC-157 is a 15-amino-acid fragment of a protective protein from human gastric juice, first described by researchers in Zagreb in the early 1990s. It is the most widely researched peptide in this group for musculoskeletal injury.
- Rat Achilles tendon: faster restoration of tendon integrity, higher load-to-failure and better walking function up to day 14 (Staresinic, J Orthop Res 2003).
- Blood vessels: VEGFR2 activation and faster blood-flow recovery in ischemic rat limbs (Hsieh, J Mol Med 2017).
- Tendon cells: faster fibroblast migration via FAK - paxillin signalling (Chang, J Appl Physiol 2011).
- Evidence level: a 2025 systematic review included 36 studies, 35 preclinical and one clinical, and found no controlled human trials and no clinical safety data.
TB-500 and thymosin beta-4: cell migration and wound closure
Thymosin beta-4 is a 43-amino-acid protein present in almost every cell and released by platelets at wound sites. It binds G-actin, the building block cells use to move. TB-500 is a 7-residue synthetic fragment (Ac-LKKTETQ, residues 17-23) that keeps the actin-binding motif.
- Rat skin wounds: 42 % more re-epithelialisation at day 4 and up to 61 % at day 7 versus saline (Malinda, J Invest Dermatol 1999).
- Mouse heart: improved cardiac cell survival and function after coronary ligation (Bock-Marquette, Nature 2004).
- Humans: in two phase 2 trials in stasis and pressure ulcers, healing was accelerated by almost a month in patients who healed (Treadwell, Ann N Y Acad Sci 2012).
- Caveat: the human and most animal data used full-length thymosin beta-4, not the TB-500 fragment.
GHK-Cu: collagen, skin and gene expression
GHK-Cu is the copper complex of the tripeptide glycyl-histidyl-lysine, found naturally in human plasma. Loren Pickart identified it in 1973, and plasma levels reportedly fall from about 200 ng/mL at age 20 to about 80 ng/mL by age 60. It carries copper to cells and acts as a signal for matrix production.
- Fibroblast cultures: collagen synthesis rose at picomolar concentrations and peaked at 1 nanomolar (Maquart, FEBS Lett 1988).
- Animal wounds: better wound contraction, granulation tissue and blood-vessel growth in rat and rabbit models.
- Gene data: Connectivity Map analysis suggests GHK changes the expression of about 31 % of human genes by 50 % or more, shifting them towards a repair profile (Pickart and Margolina, 2018).
- Humans: a 12-week study of 71 women using a topical GHK-Cu cream reported increased skin density and thickness and reduced wrinkle depth.
KPV: the anti-inflammatory tripeptide
KPV (Lys-Pro-Val) is the last three amino acids of the hormone α-MSH. It keeps α-MSH's anti-inflammatory activity without the pigmentation effect, and enters gut and immune cells through the PepT1 transporter, which is up-regulated in inflamed colon.
- Mouse colitis: KPV reduced DSS- and TNBS-induced colitis and lowered pro-inflammatory cytokines (Dalmasso, Gastroenterology 2008).
- Recovery: treated mice recovered earlier and regained weight faster in two colitis models (Kannengiesser, Inflamm Bowel Dis 2008).
- Cells: nanomolar KPV inhibited NF-κB and MAP-kinase signalling in human intestinal cells and T cells.
- Evidence level: no published controlled human trials.
KPV is not a repair peptide in the strict sense. It is included here because prolonged inflammation is one of the main reasons healing stalls, and it is the fourth component of the KLOW blend.
GLOW and KLOW: combining the mechanisms
GLOW is a three-peptide research blend of 10 mg BPC-157, 10 mg TB-500 and 50 mg GHK-Cu (70 mg per vial). The logic in one line: GHK-Cu builds the matrix, TB-500 moves the cells and BPC-157 supports blood supply. KLOW contains the same three plus 10 mg KPV (80 mg per vial), adding an anti-inflammatory signal to the repair trio.
Neither blend has been evaluated as a combination in published studies. Their design rests on the separate findings for each component. For a closer look at when researchers choose one over the other, see our GLOW vs KLOW comparison; for the two-peptide pairing, see BPC-157 vs TB-500.
Evidence at a glance
| Peptide | Studied for | Key finding | Best evidence |
|---|---|---|---|
| BPC-157 | Tendon, ligament, gut, vessels | Faster rat Achilles healing (2003) | Animal |
| TB-500 / Tβ4 | Wound closure, cell migration | Up to 61 % faster rat wound closure (1999) | Phase 2 (full Tβ4) |
| GHK-Cu | Collagen, skin, gene expression | Collagen synthesis at 1 nM (1988) | Small cosmetic trials |
| KPV | Gut and skin inflammation | Reduced colitis in mice (2008) | Animal |
| GLOW | Skin and connective tissue | BPC-157 + TB-500 + GHK-Cu | Component data only |
| KLOW | Repair plus inflammation | GLOW + KPV | Component data only |
Regulatory status in 2026
- None of these peptides is an approved medicine in the EU or US for tissue repair.
- WADA prohibits BPC-157 (S0, non-approved substances) and thymosin beta-4 and its derivatives including TB-500 (S2, growth factors) at all times.
- In July 2026 an FDA advisory committee voted 8-6 to recommend BPC-157, TB-500 and KPV for the 503A compounding bulks list. FDA rulemaking is still pending, and this is not a drug approval.
- GHK-Cu is widely used as a cosmetic ingredient in topical skin products (INCI: copper tripeptide-1).
What to check in research-grade material
Small peptides are easy to mislabel and blends are harder to verify than single compounds, so each component needs its own identity check. Look for HPLC purity, LC-MS identity for every peptide in the vial and a batch-specific certificate. Cryopept's healing peptides are ≥99 % by HPLC, identity-confirmed by LC-MS and supplied lyophilized, with an internal batch test protocol (COA) for each lot.
Research information only, not medical advice. Cryopept Labs products are for laboratory research use only.
