- You've reconstituted two or more peptides in one vial (a "blend" or "cocktail" vial)
- You bought a pre-blended vial from a supplier (GLOW, KLOW, Wolverine, CJC-1295/Ipamorelin combo)
- You're combining two separately-shipped peptides into a single vial to reduce injection count
- You need to verify that a supplier's pre-blend ratio actually delivers therapeutic doses of every component at your target draw volume
Free Online Tool
Peptide Stack & Blend Calculator
Calculate exact per-component doses for multi-peptide blends like GLOW, KLOW, Wolverine, and any custom stack. Enter each peptide's mg amount, your total BAC water volume, and your target draw — get the mg, mcg, and syringe units delivered for every component in the vial. No signup required.
This is a different tool than the single-vial Peptide Reconstitution Calculator. A single calculator handles one peptide in one vial. The stack calculator handles two or more peptides reconstituted together in the same vial — which is how GLOW, KLOW, Wolverine, CJC-1295/Ipamorelin, and most community blends are actually prepared. Each component has its own per-mL concentration, and a single draw delivers all of them proportionally. I built this after running the per-component math by hand across dozens of blend protocols on Peptide Dosing Protocols — and realizing no single tool on the web handles both sides of the math (per-component delivery + target-unit reverse calculation) cleanly.
Built and maintained by Garret Grant - Founder & Lead Researcher, B.S. Engineering, UCLA.
Last updated: April 2026
Human-researched and AI-assisted with full editorial review. I verify sources, rankings, and final judgments personally. See methodology.
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Units shown on U-100 insulin syringes. 1 mL = 100 units. Not medical advice — for tracking and calculation purposes only.
Need the rest of the calculator suite? Browse the full tool library.
How the Peptide Stack Calculator Works
When you reconstitute two or more peptides in the same vial, every peptide shares the same total water volume — which means each peptide has its own concentration, and every syringe draw delivers a proportional amount of each. This calculator handles that in four steps:
- 1. You enter each component in the vial separately — or pick a supported blend from search — so the calculator knows the exact mg amount for every peptide in the stack.
- 2. You set one shared BAC water amount for the whole vial, and the calculator computes the individual concentration of each peptide (mg/mL and mcg/mL) from that shared volume.
- 3. You choose either anchor-dose mode or draw-based mode. Anchor mode starts with the peptide you care about most and calculates the required draw size. Draw mode starts with a syringe pull and shows what that pull delivers across the blend.
- 4. The result card returns the draw size, draw volume, per-component delivered dose, and warnings when the math looks impractical — for example if the draw exceeds the selected syringe or lands between useful markings.
For single-vial, single-peptide reconstitution, use the standard Peptide Reconstitution Calculator.
When to Use a Stack Calculator vs. a Single Calculator
Use the stack calculator when:
Use the standard reconstitution calculator when you have one peptide in one vial and just need to know your syringe units for a given dose.
If you're running two separate vials (e.g., BPC-157 in one vial, TB-500 in another, same day), you don't need a stack calculator — run the single calculator twice.
Supported Stack Protocols
This calculator works for any combination of lyophilized peptides reconstituted in the same vial. The blend search and examples below cover the most common commercial and community stacks, but custom ratios are fully supported.
Recovery & Healing Stacks
Wolverine Stack (BPC-157 + TB-500, typically 1:1 — 10 mg / 10 mg in 20 mg total vials). GLOW Stack (GHK-Cu + BPC-157 + TB-500, typically 5:1:1 — 50 mg / 10 mg / 10 mg). KLOW Stack (GLOW + KPV, adding anti-inflammatory coverage). See the Wolverine Stack protocol, GLOW Stack protocol, and KLOW Stack protocol for full dosing context.
Growth Hormone Stacks
CJC-1295 / Ipamorelin blend (typically 1:1 — 5 mg / 5 mg in 10 mg total vials). This is the most common GH secretagogue pairing and is frequently sold pre-blended. See the CJC-1295 + Ipamorelin GH Pulse Stack for full protocol details.
GLP-1 / Fat Loss Stacks
Cagrilintide + Tirzepatide (CagriSema-equivalent, ratio-dependent on target). Cagrilintide + Retatrutide. These are almost always run as separate vials, but the calculator handles co-reconstituted variants. See the CagriSema stack and Cagrilintide + Tirzepatide stack for dosing.
Nootropic Stacks
Semax + Selank (Russian Nootropic Stack — typically equal ratio, often intranasal). See the Russian Nootropic Stack protocol.
Worked Example — GLOW Stack (50 mg GHK-Cu / 10 mg BPC-157 / 10 mg TB-500)
Here's how the math works for a standard pre-blended GLOW vial. Your supplier ships a 70 mg total vial containing 50 mg GHK-Cu, 10 mg BPC-157, and 10 mg TB-500 in a 5:1:1 ratio.
Reconstitute with 2 mL BAC water. That yields:
GHK-Cu concentration
50 mg ÷ 2 mL = 25 mg/mL (25,000 mcg/mL)
BPC-157 concentration
10 mg ÷ 2 mL = 5 mg/mL (5,000 mcg/mL)
TB-500 concentration
10 mg ÷ 2 mL = 5 mg/mL (5,000 mcg/mL)
Your target is 2.5 mg GHK-Cu per dose. Dose volume:
2.5 mg ÷ 25 mg/mL = 0.1 mL = 10 units on a U-100 syringe
At that 0.1 mL draw, you're also delivering:
- BPC-157: 0.1 mL × 5 mg/mL = 0.5 mg (500 mcg) — inside typical BPC-157 daily range
- TB-500: 0.1 mL × 5 mg/mL = 0.5 mg (500 mcg) — inside typical TB-500 loading range
The 5:1:1 ratio works because anchoring your draw to a therapeutic GHK-Cu dose automatically delivers therapeutic BPC-157 and TB-500 doses in the same injection. That's the design logic behind every pre-blended stack — the ratio is chosen so one draw hits every component's target range. If you're running a custom ratio, the calculator above verifies whether your draw actually lands in range for every peptide.
How to Read Your Stack Calculator Results
The calculator returns five data points per peptide in the blend:
Peptide name — what the component is
Concentration — mg/mL and mcg/mL for that component alone
Dose at target draw — how much of that peptide you're actually getting per injection
Assessment — whether that dose falls inside, below, or above typical community/protocol ranges for that peptide
Doses remaining in vial — how many injections the vial provides at your current draw volume
Match the assessment column against the protocol page for each peptide. If the assessment shows "below typical range" for the anchor peptide, either your target dose is too low or your vial size doesn't deliver therapeutic amounts — adjust your BAC water volume or switch to a higher-concentration vial.
Common Stack Calculator Mistakes
Four calculation errors I see repeatedly when auditing community protocols:
Drawing based on total vial weight instead of individual peptide weight
A 20 mg Wolverine vial is 10 mg BPC-157 + 10 mg TB-500, not 20 mg of each. Concentration math must use the individual mg, not the total.
Ignoring the bystander dose
If you draw for a high-range dose of the anchor peptide, the other components scale proportionally. A 5 mg GHK-Cu draw from a GLOW vial delivers 1 mg each of BPC-157 and TB-500, which exceeds typical daily ranges for both.
Using the single-peptide reconstitution calculator on a blend vial
The single calculator returns the concentration for the total vial weight, which misrepresents every individual component. Always use the stack calculator for multi-peptide vials.
Reconstituting with too little water for the shortest-stability component
Most blends include TB-500, which has a reconstituted stability window of roughly 1–2 weeks refrigerated. If your BAC water volume gives you 60+ doses per vial, you won't finish the vial inside the TB-500 stability window. See the reconstitution guide for stability details.
Save Your Stack Calculations
Stop re-entering the same blend values every time you prep a new vial. PepPal lets you save, name, and revisit stack calculations with notes — so your GLOW math, your CJC/Ipa math, and your custom blend math are one tap away.
Save a calculation with the button below the calculator, or open the PepPal homepage to see the full saved-calculations feature.
Verified Suppliers for Stack Protocols
Running a pre-blended stack requires a supplier that ships verified-ratio vials with matching COAs for every component. The two suppliers below are PepPal's recommended sources — both are USA-based, Finnrick-tested, and honor the PEPPAL discount code at checkout when eligible. For the full side-by-side, read Peptide Partners vs Orbitrex.
Related Calculators and Guides
For single-vial reconstitution math, use the Peptide Reconstitution Calculator. For blend strategy and safety before you reconstitute, read Peptide Stacking 101. For step-by-step mixing technique, read How to Reconstitute Peptides. For the full dosing protocol on any individual peptide in your stack, browse Peptide Dosing Protocols — every stack page includes the per-component dosing math this calculator operates against.
Frequently Asked Questions
What is a peptide stack calculator?
A peptide stack calculator handles the math for multi-peptide blends reconstituted in a single vial. Unlike a single-vial reconstitution calculator, which assumes one peptide in one vial, the stack calculator computes individual concentrations and per-draw deliveries for every peptide in the blend. You enter each peptide's mg amount separately, the total BAC water volume, and your target draw — the calculator returns the exact mg, mcg, and syringe units for every component. This is the correct tool for GLOW, KLOW, Wolverine, CJC-1295/Ipamorelin, and any custom blend. For single-peptide vials, use the standard peptide reconstitution calculator instead.
How do I calculate doses for a pre-blended peptide vial?
Enter each component's individual mg amount, not the total vial weight. A 20 mg Wolverine vial is 10 mg BPC-157 plus 10 mg TB-500 — enter both as separate 10 mg components. Add your total BAC water volume (typically 2 mL for most blends), then enter your target draw in mcg or units. The calculator returns the per-component concentration, the dose delivered for each peptide at your draw volume, and the assessment of whether each dose lands inside typical protocol ranges. For the full blend ratio math behind common stacks, see the relevant stack protocol page.
How does the GLOW stack calculator math work?
GLOW is typically a 5:1:1 ratio — 50 mg GHK-Cu plus 10 mg BPC-157 plus 10 mg TB-500 in a 70 mg total vial. Reconstituted with 2 mL BAC water, GHK-Cu is at 25 mg/mL and the two supporting peptides are at 5 mg/mL each. A 0.1 mL (10 unit) draw delivers 2.5 mg GHK-Cu, 500 mcg BPC-157, and 500 mcg TB-500, all inside typical ranges. The calculator handles this automatically and also supports non-standard ratios. See the full GLOW Stack protocol for dosing context.
Can I calculate a Wolverine stack (BPC-157 + TB-500) blend?
Yes. Wolverine is typically a 1:1 ratio — equal mg of BPC-157 and TB-500 co-reconstituted. Enter both components with their individual mg values (usually 10 mg each for a 20 mg total vial). Because the ratio is 1:1, a single draw delivers the same mcg of both peptides. With 2 mL BAC water, a 10 unit draw delivers 500 mcg of each. The calculator verifies this math automatically and accounts for alternate ratios if your supplier ships a different blend. Full protocol: Wolverine Stack.
What's the difference between the stack calculator and the single reconstitution calculator?
The single reconstitution calculator assumes one peptide in one vial — it returns one concentration and one syringe unit output. The stack calculator assumes two or more peptides in one vial — it returns a separate concentration for every component and tells you the exact dose of each peptide delivered in a single draw. If you use the single calculator on a blend vial, the concentration will be wrong for every individual peptide because it divides the total vial weight by the water volume instead of the individual peptide weights. Always use the stack calculator for blends.
How much BAC water should I use for a peptide blend?
Most pre-blended vials reconstitute cleanly with 2 mL BAC water, but the right volume depends on your target draw and the shortest-stability component. TB-500 is the most common limiting factor — it's stable for roughly 1–2 weeks refrigerated once reconstituted, so if your water volume produces 30+ doses per vial, you likely won't finish before TB-500 degrades. The calculator's reverse-BAC feature lets you enter a target syringe unit draw and computes the BAC water volume that produces it. For mixing technique, read the reconstitution guide.
Can I calculate a custom blend with any peptides?
Yes. The calculator supports 2–5 peptides in any combination with any mg ratio. Enter each peptide's name and mg amount separately, then your total BAC water and target draw. The calculator returns per-component concentration and per-draw delivery regardless of which peptides you're combining. For safety context on custom blends, including which peptides shouldn't be combined due to stability or pathway conflicts, read Peptide Stacking 101 before reconstituting. Not every peptide pair is appropriate to co-reconstitute.
Why does my anchor peptide dose determine the other doses in the blend?
Because every peptide in a blend shares the same total BAC water volume, they're all diluted into the same solution. When you draw a volume from the vial, you pull a proportional amount of every peptide in that draw. The "anchor" peptide is typically the one with a narrow therapeutic range — GHK-Cu in GLOW, or whichever component you're optimizing against. Once you set your anchor dose, every other peptide's dose is mathematically fixed by the blend ratio. The calculator shows you all of them so you can verify the non-anchor peptides land in acceptable ranges.
Does this calculator work for two separately-injected peptides?
If you're running two peptides in two separate vials on the same day, you don't need the stack calculator — run the single reconstitution calculator twice, once per vial. The stack calculator is specifically for peptides that share a vial. Some protocols run co-administered but separately-reconstituted peptides (e.g., BPC-157 and TB-500 in two different vials injected back-to-back). That's a single-calculator workflow. The stack calculator is for the case where both peptides were reconstituted in the same vial together.
Is the stack calculator free?
Yes. The peptide stack calculator is completely free with no signup required. You can save calculations with custom names and notes by creating a free PepPal account on the homepage, which lets you revisit past blend setups without re-entering values every time. The calculator itself works without any account — enter your values, get your results.
For Laboratory Research Use Only
For tracking and calculation purposes only. Not medical advice. This tool is for informational and research calculations only and does not provide medical guidance. Always consult qualified professionals for any health-related decisions.
