The KLOW peptide blend is the GLOW blend (GHK-Cu, BPC-157 and TB-500) with a fourth peptide added: KPV, a small anti-inflammatory fragment of the hormone alpha-MSH.[1] It is marketed for skin, injury recovery and inflammation and sold as a research-use-only vial. No human or animal study has tested KLOW as a blend, and FDA found no human data on KPV by any route.[17][5]
This guide covers what’s in KLOW, what KPV adds, how KLOW compares with GLOW, the evidence, side effects, dosage and the 2026 regulatory changes. For the three shared ingredients in depth, see our GLOW peptide blend guide, and for related compounds, the healing and skin peptides hub. For BPC-157 and TB-500 alone, see our Wolverine stack guide.
What is the KLOW peptide blend?
Because KLOW is not an approved drug, it has no official formula or label: the amount of each peptide in a vial is whatever the maker chooses, and no study has tested any version of the blend.[5][17] Ask what is in a product, and how it was tested, before trusting any dose on it.
| Ingredient | What it is | Best human evidence |
|---|---|---|
| GHK-Cu | Copper-binding tripeptide found in blood | Small topical skin trials[14] |
| BPC-157 | 15-amino-acid peptide based on a stomach protein | Small uncontrolled pilots[12] |
| TB-500 | Fragment of thymosin beta-4[16] | None[5] |
| KPV | Three-amino-acid fragment of alpha-MSH[1] | None[5] |
What is KPV?
KPV is a tripeptide made of three amino acids: lysine, proline and valine. It is the tail end of alpha-melanocyte-stimulating hormone (alpha-MSH), and it keeps that hormone’s anti-inflammatory effects without its skin-darkening effect.[1]
What the research shows, all in mice or cells:
- Colitis: KPV given in drinking water was absorbed by the gut through a transporter called PepT1 and reduced chemically induced colitis in mice.[2]
- Survival in severe colitis: in a German study, KPV sped recovery from colitis, and in mice with a defective melanocortin receptor it prevented all deaths in the treated group.[3]
- Targeted delivery: KPV packed into nanoparticles and taken by mouth eased ulcerative colitis in mice.[4]
FDA found no clinical studies of KPV in people, no animal toxicity studies, and no adverse event reports. In a lab test on human skin, KPV did not pass through the skin well.[5]
KLOW vs GLOW
| GLOW | KLOW | |
|---|---|---|
| Ingredients | GHK-Cu, BPC-157, TB-500 | GHK-Cu, BPC-157, TB-500, KPV |
| Marketed for | Skin, hair, recovery | Skin, recovery, inflammation and gut |
| Studied as a blend? | No[17] | No[17] |
| Human data on the added peptide | Not applicable | None for KPV[5] |
Because KPV has no human data, KLOW is not better supported by evidence than GLOW. It adds a fourth ingredient whose effects in people are unknown. The only animal study combining two of the shared ingredients, BPC-157 and TB-500, found no added benefit from combining them.[13]
KLOW peptide benefits: claims vs evidence
| Claimed benefit | What the evidence shows |
|---|---|
| Less inflammation, gut healing | KPV reduced colitis in mice[2][3]; no human studies |
| Skin quality and collagen | GHK-Cu topical trials are few and small[14]; no injected human trials[15] |
| Faster recovery from injuries | BPC-157 studies are almost all in animals[12] |
| Combined effect | Never tested; combining BPC-157 and TB-500 showed no extra benefit in rats[13] |
The ingredients’ human evidence, one by one
Because the blend itself has never been tested, the best you can do is look at each ingredient. The human data are thin for all four.
- BPC-157: a 2026 systematic review found only three human studies, with 30 people in total: a look back at 16 patients given knee injections, a pilot of 12 people with interstitial cystitis (a painful bladder condition), and an IV safety test in 2 people.[20] None had a control group. The reviewers rated the certainty of evidence very low and said BPC-157 should not be used in people outside regulated clinical trials.[20]
- TB-500: this is a short synthetic fragment of thymosin beta-4, not the full protein.[16] Human trials have used the full protein instead. In one phase 2 trial of thymosin beta-4 eye drops for dry eye, 72 people were randomized; the drops missed both main goals, though some secondary measures improved and no adverse events were observed.[21] Those results say nothing about injecting the fragment.
- GHK-Cu: human studies are mostly small trials of creams applied to the skin, not injections.[14]
- KPV: FDA found no human exposure data by any route.[9]
What users report
Side effects and safety
No study has measured KLOW’s side effects. For the shared ingredients, see the GLOW safety section, which covers FDA adverse event reports including skin and gum darkening, and possible blood-clotting and liver signals in animal studies of BPC-157.[5]
For KPV specifically:
- No human safety data and no toxicity studies in animals.[5]
- Immune reactions and impurities are FDA’s main concern for all injectable peptides in this group.[9] FDA says peptides like these can clump together (aggregate) and carry peptide-related impurities, which may trigger the immune system. It found no human exposure data for TB-500 or KPV, and only limited human data for injected GHK-Cu.[9]
- More ingredients, more unknowns: a 2026 review warns that unregulated injectable peptides carry risks from contamination and dosing errors, as well as theoretical risks such as abnormal blood vessel growth.[18]
KLOW peptide dosage
No dose of KLOW, or of KPV, has been studied in people.[5][17] In mouse colitis studies, KPV was given by mouth in drinking water or nanoparticles, not by injection.[2][4] For human doses studied for the three GLOW ingredients, see the GLOW dosage section. To convert a vial’s milligrams into syringe units, use our peptide calculator.
Is KLOW FDA approved or legal?
- Not FDA-approved. BPC-157, TB-500 and KPV are not part of any approved drug.[5]
- 2023: FDA listed KPV, BPC-157, TB-500 and injectable GHK-Cu among substances that may pose significant safety risks in compounding.[9]
- April 2026: after the nominations were withdrawn, FDA removed them from that list, which is not an approval.[9][10]
- July 2026: FDA’s compounding advisory committee reviewed KPV for wound healing and inflammatory conditions, alongside BPC-157 and TB-500.[7] FDA recommended against all three, but the committee reportedly voted 8 to 6 in favor of each.[6][8] The vote is not binding, and no rule had followed as of our last review.
- Sport: WADA bans BPC-157 and TB-500 at all times. KPV is not named on the 2026 list.[11][19]
This is general information, not legal advice.
