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Blend & Stack Calculator

For a vial that contains more than one peptide: enter each component's milligrams and the water you add, and see what a syringe draw delivers of every component. It is arithmetic on your label, not a dose recommendation, and in a fixed-ratio vial no component can be dosed on its own.

Related: the reconstitution calculator for single-peptide vials, the mixing guide, and our comparison of KLOW, GLOW and Wolverine, three blends sold under brand names.

How this tool works · sources read September 30, 2026 · Grey Peptides Editorial Board

What the calculator works out

Every number on this page comes from two inputs you supply: the milligrams of each component printed on the vial's label and the millilitres of water you add. The concentration of each component is its milligrams times 1,000, divided by the water, in micrograms per millilitre. A U-100 insulin syringe holds 100 units in 1 mL, so a draw of n units is n/100 mL, and it delivers each component's concentration times that volume. The number of draws a vial holds is the water divided by the draw.

The page runs the same three functions that our test suite checks against hand-worked cases: one for concentrations, one for what a draw delivers, and one for the draw that gives a chosen amount of one component. It treats the water you add as the volume of the solution, as our reconstitution calculator does, and it flags any draw larger than a 100-unit syringe holds. It never suggests an amount: the draw box starts at 10 units as a piece of arithmetic, and target mode waits for you to enter a figure.

The ratio trap

A blend is a fixed-ratio mixture. Whatever you draw, every component comes out in the proportion it went in, so no component can be dosed on its own. Take the four-peptide example composition, 50 mg of GHK-Cu with 10 mg each of BPC-157, TB-500 and KPV, dissolved in 2 mL. The vial then holds 25,000 micrograms of GHK-Cu per millilitre and 5,000 of each of the others. A 10-unit draw, 0.1 mL, delivers 2,500 micrograms of GHK-Cu and 500 of each of the other three. Doubling the draw to raise one component doubles all four.

That arithmetic has two consequences people often miss. First, the component with the most mass sets the exposure: in that composition GHK-Cu is 62.5% of the peptide in the vial, so any amount chosen for a minor component brings five times as much GHK-Cu with it. Second, the components run out together. A vial made up in a fixed ratio has no leftover of the component you care about; its number of doses is the same for every ingredient. The second calculator mode makes this visible: pick one component and an amount, and it shows the draw and everything that comes along with it.

A stack, several separate vials taken together, avoids the ratio trap because each vial is measured on its own, but it multiplies everything else: separate labels to trust, separate draws to get right, and interactions that nobody has measured.

The six example compositions

The presets are generic compositions, named by their contents, never by a brand. Each is a starting point to overwrite with what your own label says.

  • GHK-Cu, BPC-157, TB-500 and KPV, 80 mg (50/10/10/10). GHK-Cu is five-eighths of the mass, so it dominates every draw; the other three arrive in equal amounts.
  • GHK-Cu, BPC-157 and TB-500, 70 mg (50/10/10). The same pattern without KPV: GHK-Cu is about 71% of the mass.
  • BPC-157 and TB-500, 20 mg (10/10). Equal parts, so every draw delivers the same micrograms of each.
  • CJC-1295 without DAC and ipamorelin, 10 mg (5/5), and tesamorelin and ipamorelin, 10 mg (5/5). Equal-part pairs of a growth-hormone-releasing-hormone analogue and a ghrelin mimetic.
  • Cagrilintide and semaglutide, 10 mg (5/5). Equal parts by mass; the tested combination was given as its own trial product.

Choosing a preset also lists the encyclopedia entry for each component, where its human evidence, regulatory status and sport status are set out on their own. Changing any milligram figure, or adding a component, recalculates everything at once.

No blend here has been studied as a blend

The example compositions are taken from what is sold, not from trials. For the healing blends, the individual evidence is thin before anything is combined: BPC-157's human record is a telephone chart review of 16 knee patients and a two-person safety pilot of intravenous infusion.1 2 The only published study that gave BPC-157 and TB-500 together was in rats with injured Achilles tendons, not people.3 No study has tested GHK-Cu, BPC-157, TB-500 and KPV together, in any species we could find, nor CJC-1295 with ipamorelin.

Two of the examples contain an approved drug, which is where confusion is most likely. Tesamorelin is approved on its own, as EGRIFTA, to reduce excess abdominal fat in adults with HIV, and its label carries warnings on fluid retention, joint pain, carpal tunnel syndrome and glucose intolerance;4 mixing it with ipamorelin produces something that has never been tested or approved. Cagrilintide with semaglutide has been tested, as CagriSema, in REDEFINE 1: 3,417 adults, a 20.4% weight loss over 68 weeks against 3.0% on placebo.5 That trial used Novo Nordisk's product under trial conditions. A vial sold online as the same pair is not that product, and FDA has warned companies selling unapproved semaglutide and related drugs falsely labelled for research use.6

What the numbers cannot tell you

The calculator believes your label, and labels can be wrong. When researchers test-bought semaglutide vials from illegal online pharmacies, the vials held 29% to 39% more semaglutide than their labels stated, while the measured purity was 7.7% to 14.4% against the 99% printed on them.7 A blend multiplies that problem: each component can be off in its own direction, and the ratio on the label may not be the ratio in the vial. Only testing the vial itself can tell, and our verification guide explains how.

Three further limits apply to every result. The arithmetic ignores the small volume the powder itself adds and any liquid left in the vial or syringe. Nobody has published how these peptides behave in solution together, so whether one component degrades another, or clumps, is unknown. And a correct calculation says nothing about whether a combination is safe or does anything; for most of these components, that has not been tested in people even one at a time.

Legal status and sport

None of the research-peptide blends is an approved drug. FDA's compounding advisory committee reviewed BPC-157, TB-500 and other peptides in July 2026, and our regulatory tracker follows what FDA decides.8 For athletes, the World Anti-Doping Agency's list names BPC-157 under S0, non-approved substances, and a blend containing it carries that status with it.9 Each component's own entry, linked beside every example, gives its evidence and status in full.

Sources

  1. Lee, E. et al. (2021). Intra-articular injection of BPC 157 for multiple types of knee pain. Alternative Therapies in Health and Medicine, 27(4), 8–13. PMID: 34324435
  2. Lee, E. et al. (2025). Safety of intravenous infusion of BPC157 in humans: a pilot study. Alternative Therapies in Health and Medicine, 31(5), 20–24. PMID: 40131143
  3. Biçer, O. et al. (2026). Effects of BPC-157 and TB-500 on Achilles tendon healing in rats: a histopathological and biomechanical study. Joint Diseases and Related Surgery, 37(3), 822–837. PMID: 42542926
  4. Theratechnologies Inc. EGRIFTA SV (tesamorelin) for injection, US prescribing information: section 5 (fluid retention with edema, arthralgia and carpal tunnel syndrome; glucose intolerance, HbA1c 6.5% or higher in 5% vs 1%; hypersensitivity; injection site reactions 25% vs 14% over 26 weeks; evaluate glucose before and during therapy). DailyMed version of July 31, 2026, read September 30, 2026.
  5. Garvey, W. T. et al. (2025). Coadministered Cagrilintide and Semaglutide in Adults with Overweight or Obesity. N Engl J Med, 393(7), 635-647. PMID: 40544433 · doi:10.1056/NEJMoa2502081
  6. U.S. Food and Drug Administration. FDA's concerns with unapproved GLP-1 drugs used for weight loss: warnings to companies selling semaglutide, tirzepatide, retatrutide, survodutide or mazdutide falsely labelled "for research purposes" or "not for human consumption"; buy only from state-licensed pharmacies. Content current as of September 1, 2026; read September 30, 2026. FDA
  7. Ashraf, A. R. et al. (2024). Multifactor quality and safety analysis of semaglutide products sold by online sellers without a prescription: market surveillance, content analysis, and product purchase evaluation study. Journal of Medical Internet Research, 26, e65440. PMID: 39509151
  8. US Food and Drug Administration (2026). Pharmacy Compounding Advisory Committee meeting, July 23-24, 2026: briefing documents for BPC-157, TB-500, epitalon and four other bulk drug substances. FDA
  9. World Anti-Doping Agency. The 2026 Prohibited List, in force January 1, 2026: BPC-157 named under S0 (non-approved substances); the 2027 list, published August 2026, keeps it there. Read September 27, 2026. WADA

This explainer describes how the tool works and what its numbers rest on. It is not medical advice and does not recommend any dose or product.