What is KLOW Peptide Blend?

What is in the blend

KLOW is sold as one premixed powder, not four separate vials, so the four peptides cannot be measured out separately, and the amount of each is not disclosed. What each peptide is, from FDA, PubChem and the research literature:

BPC-157. Its research is mostly in animals: a 2025 systematic review found that 35 of 36 eligible studies were preclinical.⁹ FDA says its molecular targets have not been identified and its mechanisms of action remain poorly understood.² FDA has also found several salts and derivatives sold under the same name.²

TB-500. Its sequence contains LKKTET, the actin-binding region of thymosin beta-4.³ Evidence for TB-500 itself is thin. A 2024 study noted that its biological effects had not been documented, found that it did not speed closure of scratch wounds in cultured fibroblasts, and suggested that earlier reported activity may come from its breakdown product, Ac-LKKTE.²⁷³

KPV. In cell studies, nanomolar concentrations blocked NF-kappaB and MAP kinase inflammatory signaling.¹¹ KPV enters intestinal and immune cells through PepT1, a transporter for small peptides.¹¹ FDA says its molecular targets are unknown.⁴³

GHK-Cu. A 2018 review reports that GHK stimulates collagen, elastin and glycosaminoglycan synthesis and supports the work of dermal fibroblasts.²⁸ It is thought to act as a complex with copper.²⁶ Without copper, GHK weighs 340.38 g/mol.²¹ The listing does not say which copper form or ratio the vial holds.

The vial is listed as KLOW Peptide Blend for sale. Single-peptide profiles: What is BPC-157?, What is TB-500?, What is KPV? and What is GHK-Cu?. How blends differ from single peptides is covered in Peptide blends and stacks.

What sources report

KLOW has no study of its own, so every reported effect comes from research on its parts.¹ Most of that work is in animals: BPC-157 improved healing of muscle, tendon, ligament and bone injuries in preclinical models, and KPV reduced colitis in mice.⁹¹³ In a 2026 rat study that combined BPC-157 and TB-500, the pair gave no added benefit after tendon repair.¹² Full list with evidence levels: KLOW Peptide Blend benefits and uses.

Side effects

No study has measured side effects of KLOW.¹ FDA's adverse event database includes reports in people using BPC-157 of an injection-site reaction, of shortness of breath, and of skin and gum darkening in a woman who injected it with TB-500; her reaction returned when she used the product again.² FDA says it is unclear whether BPC-157 caused these events.² FDA says the potential human safety risks of TB-500 and KPV are unknown.³⁴ Full list: KLOW Peptide Blend side effects.

Dosage information

No human dose has been established for KLOW or for any of its four peptides given by injection: a 2026 review states that dosing, frequency and duration of treatment for injectable peptides like these remain unknown,¹⁴ and USADA notes that it is unknown whether any dose of BPC-157 is safe.²⁹ Published doses come from studies of single parts, in animals and in a few small BPC-157 studies in people, and they are not guidance for people.³⁰² Full details: KLOW Peptide Blend dosage.

Reconstitution and storage

KLOW arrives as one freeze-dried powder, so a diluent added to the vial reaches all four peptides at once. The supplies listed for this vial include bacteriostatic water. A DailyMed label for Bacteriostatic Water for Injection, USP states that it contains 0.9% benzyl alcohol as a preservative, is meant only for diluting or dissolving drugs for injection, is stored at 20 to 25°C, and is not for use in newborns.³¹

Concentration is the powder mass divided by the diluent volume. For the 70 mg vial, 2 mL of diluent gives 35 mg of total peptide per mL and 3.5 mL gives 20 mg/mL, assuming all of the powder dissolves. Because the split between the four peptides is not disclosed, the concentration of BPC-157, TB-500, KPV or GHK-Cu in that solution cannot be worked out. These are concentrations of a lab solution, not doses. The reconstitution calculator does the same arithmetic for other volumes, and How to reconstitute a peptide vial covers the lab steps.

No published study has tested how the four peptides behave together in one solution.¹ Data on the single peptides give some bounds:

• BPC-157 in solution was reported stable for 2 to 3 weeks at 4°C and 3 to 4 months at -20°C, figures FDA cites from a peptide seller.² FDA adds that peptides like BPC-157 can be sensitive to pH, heat, concentration and impurities, which may make them clump and break down.²
• A product data sheet cited by FDA says TB-500 in solution should be kept sealed, away from moisture and light, under nitrogen, for up to 6 months at -80°C or 1 month at -20°C.³
• Under acid, alkali and hydrogen peroxide stress, KPV breaks down mainly into lys-pro-diketopiperazine (2015 lab study).³²
• In a 2016 lab study, the GHK tripeptide stayed stable in water and in pH 4.5 to 7.4 buffers for at least two weeks at 60°C.³³

General storage guidance is in How to store peptides, and diluents and syringes are described in Peptide supplies explained.

Regulatory status

United States. FDA says BPC-157, TB-500 and KPV are not components of any FDA-approved drug.²³⁴ All three, plus GHK-Cu for injection, were in category 2 of FDA's compounding policy, the group of nominated substances that may present significant safety risks.^34353637 FDA now lists them as previously in category 2, after the nominators withdrew their nominations.³⁴ Since a May 14, 2026 update, GHK-Cu for routes other than injection is back in category 1, the group under evaluation, and FDA plans to consult its advisory committee on it before the end of February 2027.³⁸³⁹

Ahead of a July 2026 advisory committee meeting, FDA staff proposed keeping BPC-157, KPV and TB-500 off the 503A bulks list, the list of bulk substances pharmacies may use to compound.²³⁴ They cited poor characterization, missing human safety data and the risk of immune reactions.^2341718 Trade press reported that the Pharmacy Compounding Advisory Committee then voted 8 to 6, with one abstention, in favor of allowing all three to be compounded.¹⁹ FDA is not bound by that vote, and a change would require formal rulemaking.¹⁹ As of October 24, 2026, a Federal Register search found only FDA's April 16, 2026 meeting notice and no proposed rule.⁴⁰

Research-use labels. In a March 31, 2026 warning letter to a peptide seller, FDA said evidence from the seller's website showed its products were intended as drugs for human use, despite "Research Use Only" labeling.⁴¹ That letter concerned retatrutide and tirzepatide, not KLOW's parts.⁴¹

Canada. Health Canada's April 9, 2026 advisory lists all four of KLOW's peptides (BPC-157, TB-500, KPV and GHK-Cu) among examples of unauthorized injectable peptide drugs it has seized.⁴² It says unauthorized drugs are illegal in Canada and that "research use only" labeling does not make them legal.⁴²

Sport. BPC-157 and TB-500 are prohibited under WADA rules, as the questions below explain.⁷⁸